Extreme Novice Installing PowerTrax No-Slip, TrueTrac, Crown 4340 rear axle shafts - Page 2 - JeepForum.com
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Unread 07-05-2011, 03:34 PM   #16
FarmerinVA
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Thanks, aslack99 and andy02. And those sound like good tips. You sent me off searching the Internet for a photo of what the “outer ear” is. That’s how much of a novice installer I really am.

Also, andy02, my father-in-law is Air Force, and he just helped me install the TrueTrac in the rear. He'll be excited to see that you are reading from Germany!

Now, time for a …

Performance Report on the PowerTrax No-Slip in the Front

I’m going to short-form this because JF has many such reports. I’ll just hit the basics, in case whoever is reading this is too lazy to search out the many other threads on autolocker performance.

The unit is terrific -- it functions 100% as advertised and I’m 100% satisfied. I would definitely install this thing again. The traction improvement is phenomenal. Trails that were guaranteed-stuck are now guaranteed-easy.

In 2WD:
  • When I first installed it, I noticed that when I was on dry ground, the steering wheel seemed a bit stiffer in the exact center position. The sensation was as if the power steering was beginning to go bad. There was no such effect once I got past about 1/8 turn to the left or right, however, and the effect wasn’t problematic at all. Now, 6+ weeks later, I don’t notice this anymore. Did the unit break in, or have I just gotten used to it? I don’t know. Either way, I don’t notice a steering effect of any kind now when I’m in 2WD.
  • Otherwise, the unit is completely invisible when I’m in 2WD. I can make very sharp turns normally. There is absolutely no negative effect.
  • I do not hear any loud locker bangs.
  • I do hear a single click as I turn sharply in either direction. This is not particularly loud; it sounds very much like breaking a toothpick. The manufacturer’s write-up says that this is the sound of the locker disengaging to let the wheels differentiate around turns. And this sound became noticeably quieter after the first two days of driving, and now is quite faint. I assume that what’s happened is that the unit has become thoroughly seated and covered with diff oil now that it’s been driven a bit, and that explains why it’s so quiet.
  • I do not hear any sound as I straighten out after a turn.
In 4WD in mud/dirt/gravel/logs:
  • WOW. When you put the Jeep into 4WD, you have got traction to spare. The axle lock-up is instant and silent.
  • You feel the locker immediately via a stiffer steering wheel. How stiff depends on good the footing is; better footing = stiffer steering wheel, worse footing = no stiffness in the steering wheel. Just like a selectable locker.
  • I have not had any problem turning sharply in the mud. As far as I can tell, the unit stays locked in the very slippery mud even on sharp turns (there seems not to be enough over-spin force to automatically unlock a wheel), but I don’t experience much understeer. A little, but nothing unmanageable.
  • Even though I have driven plenty of locker-equipped vehicles before, I’d never driven one with a front locker and a rear open differential. So, as a test, that’s how I ran my Jeep for six weeks, before I put in the rear TrueTrac. I immediately laughed at myself -- it was instantly clear that I wasn’t going to need the rear TrueTrac very often. The front locker, by itself, consistently pulled me through mud that was over the top of the rims on my wheels (15” rims with 31” tires, so that’s almost 2 foot deep mud). In fact, I never got it stuck, not even once, and I did quite a few stupid things.
  • The unit really shines when you lift a front wheel going over a log in the mud. That’s a particular challenge where my open diff vehicles have consistently failed. No problem here -- with the unit locking the front axle, the upper wheel on the slippery log doesn’t spin any faster than the lower wheel in the muck. The Jeep basically treats a log-jump the same as anything else in the trail. Absolutely no drama -- up and over.
  • Out of curiosity, I left the Jeep in 2WD and dug a hole with the back end in some really bad muck, leaving the Jeep on about a 20 or 30 degree angle, stuck in 2WD. I then engaged the 4WD from a dead stop, with the passenger side wheel barely touching the ground. No problem, the Jeep climbed right out, slinging mud from both front tires.
In 4WD on dry ground:
  • You definitely feel the locker on dry ground, and it’s not necessarily a good feeling. The Jeep experiences a pretty severe understeer on dry ground, just as with a selectable locker.
  • Going forward, the unit does unlock and articulate around turns, but somewhat grudgingly when you are going at slow speeds. It would much rather stay locked and go straight.
  • Reversing, which I have only tried at slow speeds, the unit doesn’t want to unlock. This can make reversing a challenge in 4WD on dry ground, as you will definitely drag one of the wheels.
  • So, this locker isn’t great on dry ground. But you aren’t supposed to run 4WD on dry ground even you have open diffs, so this doesn’t lose you much.
What have I lost with the autolocker, as opposed to the selectable locker in the front? Little to nothing, so far as I can tell.
  • I would be willing to drive a bit faster on moderately firm ground, in 4WD, if I still had the open differentials (selectable locker turned off) … but I generally don’t see the need to go fast in 4WD.
  • I can imagine a situation where making a tight turn in 4WD open would be easier than 4WD locked … however, I haven’t run into that situation yet, even though I’ve been driving quite a bit in the woods where spaces are tight.
  • And I know that 4WD open is better for high speed snow driving, but I don’t see much snow.
In short, this is a big success. Cheap, easy to install, and great results. I love that it's idiot proof -- no air compressor to break, no hoses to snap, no electrical gremlins to chase, no cables to get out of adjustment.

I have now installed the TrueTrac in the rear, so I also can report how these work together. Wonderfully! When you have both, you have a great combo: run the TrueTrac in 2wd if you need to go fast or you need to do tight turns, then pop it into 4WD when the going gets really nasty.

So, next, let's get to the installation of the TrueTrac.

__________________
My do-it-yourself install thread for a TrueTrac in the rear, upgraded shafts, and a PowerTrax No-Slip in the front:

http://www.jeepforum.com/forum/f9/ex...hafts-1234745/
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Unread 07-05-2011, 04:03 PM   #17
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Great pictures and commentary .
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Unread 07-05-2011, 09:12 PM   #18
FarmerinVA
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Thanks, IslandTJ. Your posts have helped me a bunch, and are part of the reason I chose the TrueTrac for the rear.

Speaking of ...

The Rear Axle – TrueTrac and Crown 4340 alloy axle shafts

Or Rear Beam Iron (RBI) axle, as Jeep calls it. (Who comes up with these names?)

Here are the specs for the rear … I mean, RBI axle.



And here are the tools and torque specs, in order. Everything is a regular six-point socket unless otherwise specified:
  • Wheel lug nuts = 19mm = 90-110 lbs
  • Brakes – nothing needed here! You aren’t messing with the brakes this time.
  • Differential cover bolts = ½ inch = 30 lbs (35lbs if using a LubeLocker gasket)
  • Differential case lock bolt, or as Jeep calls it, the "pinion mate shaft lock screw" = ¼ inch 12-point = 12 lbs torque if you are reinstalling (but we won't be reinstalling it permanently)
  • Bearing cap bolts = 5/8 inch = 57 lbs
  • Ring gear bolts = 3/8 inch = 70-90 lbs
  • Dial caliper with magnetic base, for measuring ring gear backlash
  • Micrometer (not strictly needed but will save you a lot of trial and error when selecting shims for the backlash)
  • Set up bearings (make your own from your old bearings if you are adventurous; buy or borrow set-up bearings if you’re like me)
  • New bearings sized for the Dana 35 carrier (or you can reuse your old bearings if you have a bearing puller and are VERY confident that you won’t damage them in the removal)
  • Set of shims sized for the Dana 35 carrier
  • Some way to install the new bearings – either a bang-on method (see diagram below) or access to a press (see photos below)
  • Snap ring pliers for the TrueTrac snap ring (not strictly needed but will save you aggravation)
  • Differential fill plug = rubber plug if you are using the stock cover; 9/16 or 14mm Allen/Hex bit if you are using the plug that comes with the Solid diff cover; a huge screwdriver also works = 25 lbs
  • So, for the main socket tasks, that means you need a socket wrench, torque wrench ¼ 12-point, ½, 3/8, and 5/8 inch sockets. You don’t need a 19mm socket if you just want to use your lug wrench instead.
  • Also highly recommended is a vise of some sort to hold the differential case when you are removing and installing ring gear bolts – again, my Black & Decker portable worktable worked fine for this – and a small tube of Loctite 242.
  • Two quarts differential fluid and about a tablespoon of heavy grease.
You may notice that this is a longer list of tools than we had for the front lunchbox locker. Also a more unusual list of tools (you may be thinking, "what the heck is a dial indicator?"). This is a more difficult job, to be sure, but it's still quite manageable.

A dial indicator and micrometer set can be borrowed or rented from an auto parts store. In my area, AutoZone lends them for free (with a hefty deposit, of course).

This assumes you aren't replacing the axle tube bearings and oil seals. I didn't need to, but the Crown axle shafts do come with them. I just kept them as spares. If you want to replace those, you should get a slide hammer/puller and a bearing race seating tool set (or so they tell me). These also can be borrowed from AutoZone. I borrowed them but didn't use them.
__________________
My do-it-yourself install thread for a TrueTrac in the rear, upgraded shafts, and a PowerTrax No-Slip in the front:

http://www.jeepforum.com/forum/f9/ex...hafts-1234745/
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Unread 07-05-2011, 09:25 PM   #19
FarmerinVA
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To begin the rear axle install, I block the front tires and put the Jeep on tall jackstands. Jack up the back quite a ways. There is much less room to work on the rear axle than there is on the front. See this pic of my father in law – this is after I raised the jeep to the tallest setting on my 6-ton extra large jackstands. If you have access to a lift, you will definitely want it for this job, but it wasn’t so bad with my setup.



Remove the lower differential cover bolts and begin draining the diff, just as we did for the front axle. While that drains, you can get to work removing the wheels and brake drums. Once you remove the wheels, the brake drum should lift free – the only thing keeping the drums in place should be the pressure of the wheels.

Here’s where I hit my first problem, which I hope you don’t have to deal with. My ’99 Jeep appears to have the original drums, and they pretty rusted. The brake shoes inside them work fine, and they polish the inside of the drum as they are used, so that surface doesn't build up rust. But the shoes are slightly smaller than the inside of the drum, and a rust ring can build up on the inside of the drum in the area just past the part touched by the shoes.

It's hard to see in this photo but there's a rough, centimeter-wide rust ring there around the edge of the drum.



In my case, that rust ring had built up to several millimeters in height, and was enough to catch on the brake shoes and prevent me from removing the drum. Pounding on the drum didn’t work, and I didn’t want to keep pounding for fear of destroying the brake shoes. I eventually had to back the shoes off using the brake adjuster wheel on the back side of the wheel assembly. This whole process cost me at least an hour. Ugh.

Here's a page from the manual that somewhat explains what I needed to do, "adjustment with adjusting tool." I didn't have an adjusting tool so I used a screwdriver, slowly and awkwardly.



With the drums removed, you’re done fiddling with the brakes – do not remove any part of the brake innards, as that’s not necessary.
__________________
My do-it-yourself install thread for a TrueTrac in the rear, upgraded shafts, and a PowerTrax No-Slip in the front:

http://www.jeepforum.com/forum/f9/ex...hafts-1234745/
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Unread 07-05-2011, 09:36 PM   #20
FarmerinVA
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Now remove the last bolts of the differential cover and vigorously spray out the diff with brake cleaner, to remove the remaining gear oil.

As with the front axle, you need to remove the axle shafts before you can remove the carrier. Unlike the front axle, you must get inside the differential before you can remove the axle shafts. This is because the c-clips inside the differential are what keeps the stock Dana 35c’s shafts in place.

To get inside the diff, first rotate the diff until you see the lock bolt, which keeps the cross shaft in place. The head of the lock bolt is in that divot of the carrier to the right.



By the way, can you see how easy it would be to install a lunchbox locker here? The ring gear is miles away from the cross shaft! You could very easily just pop one in without taking the diff out (as apparently you can do in the front axle if you have 3.07 or 3.55 gearing). Too bad a lunchbox locker isn't very smooth in the rear, and has too large a chance of breaking those weak Dana 35 shafts. Still, it would be tempting if you were willing to drive soft and roll the dice.

Back to our task. Use a ¼ inch 12-point wrench or socket (a closed-end wrench works best) to remove the lock bolt. Once you remove the lock bolt, it looks like this:



Now push the cross shaft in. On mine – very differently from the front axle – the cross shaft slid out easily. If not, tap it out using your 3/8 socket extension or a similar small bar. Once it’s far enough out that you can see the ends of the axle shafts, push each axle shaft in enough that you see the c-clip. Here you see the cross shaft partially out, and one of the c-clips has already been removed -- the slot where the c-clip lived is visible on the left side of the spider gears, at the end of the protruding left axle shaft.



The clip either will fall out, or you can grab with your fingers or needle-nose pliers – force isn’t necessary. Here’s what a c-clip looks like – not much to it.



Once the c-clips are out, pull out the axle shafts and set them aside. Once again, be gentle and don't drag them over the oil seal and bearing inside the axle tube.



Now rotate the diff, tap the cross shaft back in, and re-install the lock bolt; otherwise, the spider gears likely will fall out when you remove the differential. Don't remove the differential case yet.
__________________
My do-it-yourself install thread for a TrueTrac in the rear, upgraded shafts, and a PowerTrax No-Slip in the front:

http://www.jeepforum.com/forum/f9/ex...hafts-1234745/
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Unread 07-05-2011, 09:50 PM   #21
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Gotta sub this man!! Nice job +4
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Unread 07-06-2011, 11:51 AM   #22
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Excellent write-up. I'm about to do almost the same thing... looking forward to the truetrac install details!
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Unread 07-06-2011, 12:19 PM   #23
FarmerinVA
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Thanks, Eric and LiveFreeOrDie. I used to live in NH -- I wish I'd had a Jeep at the time!

Now we’re ready to check the backlash on the ring gear. Actually, you also can do this before you pull out the axle shafts, but it would be more mass to move that way and therefore more error prone, so it's recommended to do it with the shafts out. You don't really need to check the backlash beforehand but it's a good trial run for when you are setting the backlash later, and it might be interesting to find out what backlash you have. If it's way, way out of spec, perhaps that means you should have your gears completely redone.

The backlash is the play between the ring gear teeth and the pinion teeth. From where you’re looking, that’s play up-and-down in the ring gear. Rock the ring gear back and forth a bit and feel the play. And then measure it, like so.

Get your dial indicator out of the case. Here’s the set I have, which is all old school (non-digital).



Here's what the 99 TJ manual says to do about setting backlash. If you find this at all clear, then you are a better reader than I am. I really don't recommend that you try to learn anything from these pages but I'm including them just in case you want them.





Yikes. I did a lot better from searching the Internet. Hopefully you can do better by reading these posts!
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My do-it-yourself install thread for a TrueTrac in the rear, upgraded shafts, and a PowerTrax No-Slip in the front:

http://www.jeepforum.com/forum/f9/ex...hafts-1234745/
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Unread 07-06-2011, 12:38 PM   #24
FarmerinVA
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Put the dial indicator on the magnetic base and install it like so, such that the probe touches the ring gear teeth in as vertical a posture as possible. Here’s how I did it. I couldn’t get everything in focus at one time, so this view shows the probe and the base in place. It's a bit hard to see but the probe is lightly touching the ring gear tooth.



Rock the ring gear up, and record this as the “up” value on the dial indictor.



It's reading "84." It doesn't matter what it starts from, as long as you remember what the number is. You are going to be subtracting one reading from the other, no matter what the starting number is. You don't need to start from zero.

Now rock it down. Be sure you are only moving it within the “play,” rather than causing the pinion/driveshaft to turn. Record this as the down value.



It's reading 95. Subtract one from the other – that’s the backlash. (95 - 84 = 11, so this backlash is 0.011 inches.) Do this several times, and at least at two different places on the ring gear, so that you make sure you are recording a consistent value. If you aren’t recording a consistent value, you’re doing it wrong, probably by moving the pinion, not just recording the “play.” (Or you have a destroyed ring-and-pinion, but it’s unlikely you wouldn’t already know that!) Be gentle -- you shouldn't need to use any force. You are looking for a tiny, easy bit of play here.

Backlash spec for a new ring-and-pinion is 0.0 to 0.15mm, or 0.005 to 0.008 inches. Mine was 0.011, which is a bit out of spec, but that is to be expected after 120,000 miles.

By the way, if you look closely you’ll see that the “up” and “down” pictures are of different tests. That’s because my pictures of the same test weren’t in good focus. As a result, the pics above make it appear that I moved the ring gear base during the up-to-down test – don’t do that! My actual tests were done correctly, and gave me a consistent 0.011.

Now you’re ready to take the differential out of the housing. Make sure the lock bolt and pinion are in place, so the spider gears inside won’t fall out. Again, mark the caps, record the markings, or take a picture so you will remember which cap goes where. My caps are helpfully already marked with an upside down "A" on both the cap and the side of the housing on the left. The same "A" is on the right side, but it's sideways. Rather than try to remember that, I just took pictures.



Then remove the bearing caps as we did for the front axle. Here's one gone on the right.



Then lift out the differential, as you did for the front axle.

Remove the ring gear and clean it, as you did for the front axle (I'm not going to repeat myself, it's the exact same drill as for the front axle), so that the bolt holes will be nice and dry for the new bolts and Loctite.



This would be a good time to take a break while the bolt holes drain and dry. I'm going to take a break too. I'll try to post again tonight but it might take me several days.
__________________
My do-it-yourself install thread for a TrueTrac in the rear, upgraded shafts, and a PowerTrax No-Slip in the front:

http://www.jeepforum.com/forum/f9/ex...hafts-1234745/
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Unread 07-06-2011, 05:39 PM   #25
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Install the ring gear on the TrueTrac, using Loctite, torquing to spec, etc. This is the same process as I described before for the front axle ring gear install.

Now we start the hard part: setting the backlash. You adjust the backlash by fitting metal shims between the sides of the TrueTrac unit and the bearings (that's in between, not at the ends!), and then partially installing the unit into the differential, measuring the backlash, removing the bearings, adding or subtracting shims, replacing the bearings, and repeating this process until you get it right. Right means within spec for the Dana 35, meaning 0.005 to 0.008, or in a pinch you can set it to the backlash that it had worn into, which in my case was 0.011. (Did you catch that pun? In my case? Hah. I'm good.)

The TrueTrac literature claims that you should err on the tight side for best limited slip performance, which would mean toward 0.005. So that's what I was shooting for.

You need setup bearings for this. Your chances of correctly estimating the backlash on the first try are nil, and you don't want to be installing and uninstalling your actual bearings -- that would take forever and probably damage the bearings. The setup bearings are a close fit but will slide on and off with a little care, with only hand pressure (a little oil helps). You only want to install the actual bearings once, at the very end.

This involves the following steps:
  • Estimate the fit of the original differential case and bearings. You can do this by setting the original case on a flat surface, sitting vertically on one of the bearings (with the bearings still on, obviously), then install the setup bearings on the TrueTrac and sit it next to the original diff. Add shims to the lower bearing until the ring gear mating surface of the TrueTrac unit seems to be at an equal height to the original diff. Flip them over and repeat for the other bearing. That should start you off in the correct ballpark.
  • Or, remove the original case bearings and compare or re-use the original shims. For this to work, the TrueTrac would need to be the exact same size as the original diff. Mine was not, and since small tolerances matter here, I recommend the other approach.
  • Once you have the shim stacks estimated, install the setup bearings and the NEW bearing cups. The setup bearings don't come with cups; you should use the actual cups you will be using in the final install, which come with the new bearings. If you are reusing bearings, re-use your old cups.
  • Remember which cups go on each side! Chances are that they are of slightly different size (particularly if they are being reused), and if you switch them during this process, all your backlash measuring will be thrown off. You might want to mark them on the side to help remember. A grease pen or even a permanent marker will work for this; put a big L and R on them. Seriously, do this -- initially I didn't, and I dropped them once and got completely confused as a result.
  • Install into the differential and ensure that there is a light preload; in other words, that it's jammed in somewhat tight. It should stay in without you needing to hold it in. If not, add a shim of exactly equal thickness on each side until you achieve a light preload.
  • Measure the backlash. You'll be out of spec, of course.
  • Remove the diff, being careful not to drop the bearings, cups, and shims, which will slide off if you aren't careful. If they slide off and get mixed up, you are back to square one. (Ask me how I know.) So don't let them slide off.
  • Add or subtract shims to move the ring gear closer to the pinion (reduces backlash) or farther from the pinion (increases backlash) while maintaining a tight fit (light preload).
  • When I say "add or subtract," you may initially be actually adding or subtracting a whole shim. As you get closer, you will probably start swapping a thicker shim for a thinner shim, or vice versa. You will start needing to measure your shims with a micrometer to do this.
  • After some trial and error, you will get it exactly right. Measure at several places around the ring gear to make sure you are getting a true reading.
  • Then take the diff off one last time, and add shims of exactly equal thickness on each side to achieve a strong preload (0.004 shim thickness in total according to the 1999 TJ manual, or 0.002 on each side).
  • Press on the real bearings, and install it one last time.
When you take the set-up bearings off that last time, don't forget to keep the shim stacks in the right place, or carefully labeled, while you move the TrueTrac unit over to wherever it is that you'll be pressing on the bearings. Again, if you drop them, scatter them or switch them, you will be back to square one! Just as a precaution, measure the final stack so that if you do somehow drop/scatter/switch them, you will have a close idea of how to recreate the stack.

Here is the package of shims I used, and the micrometer. This was a "differential rebuild kit" from Superior Axle & Gear, which came with new shims and ring gear bolts. I needed all that, so I bought the package. The package also came with pinion shims, oil seals, a pinion crush sleeve, and tooth pattern paste that I didn't need, but for some odd reason it was still less expensive than separately buying the items I did need.



Here's me installing the setup bearings for the first time. That's the TrueTrac, with the ring gear now installed. The hole is used for installing the c-clips on the axles (that comes much later). Wow, the TrueTrac is beautiful.



Here's my first install of the shimmed TrueTrac into the differential. Preload established -- it stays in without needing the bearing caps.



I said the TrueTrac is beautiful. It's also seriously heavy; I didn't weigh it but I'd guess it is 45 pounds. That's a lot to be holding at an awkward angle over your head, hoisting in and out of the axle housing while trying to keep the bearings, caps, and shims in place. As you can see from the picture above, there's not a lot of room to work. If you are lying on your side under a Jeep that's on jackstands, as I was, you'll soon be wishing that you had a proper lift. It's manageable but not exactly easy.

Now commences the backlash measuring. If you aren't 100% seating the thing correctly, your backlash readings won't be correct. For that reason, if you have any doubt, install the bearing caps each time. I did not find that necessary.

Measure, remove, adjust shims, reinstall, measure, repeat. This took me seven tries to get correct. The first time I removed it, I let the bearings and races fall off, rendering my measurements useless. Lesson learned.

Supposedly, you can estimate the shim thickness add/subtracts by the degree of backlash change needed. There are tables on the Internet for this (here's one that assumes you are aiming for 0.006 backlash). I did not find them to be particularly useful (or even to agree with each other), so I mostly ignored them and went with trial and error. It's amazing how much a tiny difference in shim thickness affects backlash.

Also, my Dana 35 has large spacers at each end of the case, where the bearing cups sit. These are removable. They are like super-thick shims (around 3/8 inch thick). They are of slightly different thicknesses, so don't treat them as interchangeable or they'll screw up your measurements. Persuade them to stay in during all this activity, by coating them with heavy grease, which acts like an adhesive and also makes it easier to get the diff in and out.

I didn't bother to take pictures of the repeated backlash measuring. They all would look exactly like the pics of the dial indicator above in Post #24. That's it -- just work that dial indicator. As I mentioned in Post #24, make darn sure that you are measuring the "play" and not turning the pinion. It helps to take a measurement on several places on the ring gear each time, to make sure that your reading is consistent.

I ended up with a solid preload and a 0.005 measurement -- the low end of spec. Perfect. The whole backlash process took me two hours. If I weren't a novice, it would have taken much less, I'm sure.
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My do-it-yourself install thread for a TrueTrac in the rear, upgraded shafts, and a PowerTrax No-Slip in the front:

http://www.jeepforum.com/forum/f9/ex...hafts-1234745/
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Unread 07-06-2011, 07:35 PM   #26
andy02
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You have my respect, I don't think I would have had the guts to pull apart my rear diff like that!
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Originally Posted by Hendrix
No one really knows the reason for LCOG Jeeps.

Its so short ****s like me and you can still get in.
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My issue was I couldn't get the balls centered. I had to use some extra force to get everything lined up right. It didn't take me long.


September 11 2001
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Unread 07-06-2011, 09:04 PM   #27
FarmerinVA
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Quote:
Originally Posted by andy02 View Post
You have my respect, I don't think I would have had the guts to pull apart my rear diff like that!
Well, I don't know if it was guts or recklessness. It certainly helped that this Jeep isn't a daily driver -- I knew that if I botched something or ran into a need for a tool or part, I could take my time sorting it out. As it turns out I didn't have any such problems but the knowledge of that option really took the pressure off. Even so, I definitely had a few moments of thinking, "Uh oh, what have I gotten myself into."

I also had two aces. One is almost literally an ace: my FIL, a former pilot and Air Force intelligence officer and commander, whose hobby is rebuilding MGs. He had never done an axle but he had a lot of car time that gave him good instincts, and he had a ton of tools in case we ran into something unexpected. He really saved my bacon when that rear drum wouldn't come off -- he figured out the problem quickly when I had no idea what to do. He also was terrific at letting me do my novice thing and let me figure out everything else for myself. He must have been laughing at me the whole time but he kept his poker face.

The other ace was my friend Eric, who works on farms in my area through his own irrigation systems and fabrication company. Here's his Jeep:



I think the only thing original on that CJ is the grille. He fabs and welds like other people check their email. He needed an extra-large air reservoir for his CJ so he just threw away the front bumper, closed the ends of a stainless steel tube, and made a bumper/reservoir. And then threw on some more tube for fishing rod holders because, hey, who doesn't need fishing rod holders? Right now, he's finishing a log cabin that he built himself. I knew I could call him to bail me out if I blew it or needed something. As it turned out, I ended up borrowing a 12-point socket I hadn't anticipated, his impact wrench, and his bearing press. By the way, he welded up the bearing press from scratch. Geez. My kid basically thinks Eric and my FIL are Batman and Superman, and frankly so do I.

With that kind of backup, I figured, why not try it? But here's the thing: I just proved that you don't need the backup after all. This job's a cinch if you take it slow.

Andy02, you are setting me up, man! I was about to talk about Eric's press anyway in the next post. So, let's get to it.
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My do-it-yourself install thread for a TrueTrac in the rear, upgraded shafts, and a PowerTrax No-Slip in the front:

http://www.jeepforum.com/forum/f9/ex...hafts-1234745/
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Unread 07-06-2011, 09:54 PM   #28
FarmerinVA
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Now it's time to install the bearings. The manual says that you can hammer them on if you have some patience and the correct tools. Basically, you take a flat piece of metal, put it on top of the bearing while being careful to keep the bearing straight-on, and tap on top of that metal (not directly on the bearing, of course) until the bearing is fully seated. These two pages explain ways to remove the old bearings if that's your plan, and to install bearings (whether new or re-used) on the differential. I'm including these pages in case you elect to try this method. I didn't.





Instead, I brought the TrueTrac over to my friend Eric's bearing press. He set it up on his forklift forks (why on the forklift forks? you don't ask "why" when Eric is doing you a favor) like so.



And after a few squeezes of the manual hydraulic pump, the bearing is fully seated.



This is another good opportunity to marvel at how beautiful the TrueTrac is. That may not matter much to the mud but you might as well enjoy how it looks. Sort of space-age.

Flip it over and repeat for the other side, and we're done installing the bearings. The install took about three minutes. It seems pretty clear that if you have any way to get access to a press, you should use that method rather than try to hammer it on.
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My do-it-yourself install thread for a TrueTrac in the rear, upgraded shafts, and a PowerTrax No-Slip in the front:

http://www.jeepforum.com/forum/f9/ex...hafts-1234745/
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Unread 07-07-2011, 06:10 AM   #29
csm41
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Location: Warren, Ohio
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Wow. Nice write up! Keep it coming!
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Unread 07-07-2011, 12:23 PM   #30
FarmerinVA
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No problem, csm41, we're almost done. All that's left is to put the completed TrueTrac back into the axle housing, install the new axles, close up the TrueTrac, and close up the diff cover.

Let's do the axles. If you can recall from the first few posts, I elected to install new Crown 4340 alloy axles. The manufacturer claims that these have a 30% increase over stock strength, which should give some extra insurance against having the TrueTrac overstress those weak Dana 35 stock shafts. This step is optional. Many people drive the TrueTrac on stock shafts with no problems. But given that my Jeep is a working vehicle that does a bunch of slow-speed equipment towing and is 100% offroad, and I wanted to have spares anyway, I think that the $329 for the upgraded shafts is a smart investment. Installing them at the same time as the TrueTrac makes everything easy. And I now have the stock shafts as spares.

Here's what's in the package, and the price as of today from Quadratec:



Notice that you get new bearings and seals. Mine also came with antilock brake tone rings, even though it wasn't advertised that way and I don't need them. A question I couldn't find a good answer to was, "do you need to install the new bearings and seals?" No, as it turns out. You can leave your old bearings and seals in place, and just keep the new ones from Crown as spares. That makes the install much easier!

I couldn't get someone to give me this answer, because it depends on whether the diameter of the new shaft is exactly the same as the old at the points where it's contacting a bearing or seal. Is the stronger shaft also a bit larger? No, it turns out that they are precisely the same.

Here are the new shafts, next to one of the old shafts:



And here's a closeup of a new shaft and the tone ring:



Here is measuring the new one, at the bearing surface:



1.41 inches. Here's measuring the old one:



It's a bit out of focus but you can see it's exactly the same: 1.41 inches. Measurements all along shaft were also equivalent. The shafts have identical profiles.

That means we don't need to remove the old bearings -- all we need to do is slide the new shaft in. (The tone ring isn't useful to me because I don't have antilock brakes, but it doesn't get in the way, so I just left it). That's easy!
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My do-it-yourself install thread for a TrueTrac in the rear, upgraded shafts, and a PowerTrax No-Slip in the front:

http://www.jeepforum.com/forum/f9/ex...hafts-1234745/
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