How-To: TJ Axle Shaft Conversion - JeepForum.com
Search  
Sign Up   Today's Posts
User: Pass: Remember?
Advertise Here
Jeep Home Jeep Forum Jeep Classifieds Jeep Registry JeepSpace Jeep Reviews Jeep Gallery Jeep Clubs Jeep Groups Jeep Videos Jeep Events Jeep Articles
Go Back JeepForum.com > Models > Jeep Wrangler Forums > YJ Wrangler Technical Forum > How-To: TJ Axle Shaft Conversion

6th Annual, Beat Your Wife to the Credit Card Sale!Flush Mount LED Bumper Lights, CREERuffstuff Axle Simple Swap Kit!

Reply
Unread 07-27-2009, 10:01 PM   #1
H3RTCH
Live Free or Die.
 
H3RTCH's Avatar
2004 WJ 
 
Join Date: Jul 2008
Location: Norfolk, VA
Posts: 1,062
How-To: TJ Axle Shaft Conversion

Many of us are familiar with the failure-prone central-axle disconnect (CAD) unit in the front axle on YJ's. Many know how frustrating it is to lose four-wheel-drive when you need it most. So we have some options.

1. Replace the failed part in the CAD system. For me that part was the vacuum line. I had no idea where that small hole in the vacuum line was. Doing this works, but you still have all the other 15-23 year old parts, that can conk out whenever. Plus, the parts aren't cheap.

2. Posi-lock or homebrew variant. This is a better idea than above, as it puts the control in the hands of the driver, instead of the vacuum system. The cons to this are it retains the relatively weak axle shafts, mainly the two-piece passenger-side shaft. Also, it doesn't simplify the 4WD very much, it still retains the CAD system.

3. Swap in TJ/XJ shafts. This in my opinion is the best option, as that's what I chose to do. The cons to this are the install is somewhat involved, you have to make a backing plate for the vacuum motor hole as well as seat a seal. Not too hard, but more involved than the other two I think. Also, your driveshaft will spin all the time, so it will likely need balanced. The pros to this are strength and simplification. Getting TJ (or '96+ XJ shafts) will give you larger 297x u-joints, as well as larger ears on the shafts. Also, it gets rid of the CAD system, which is the start of the whole problem.



This write-up will include a follow-along on how I changed my shafts from stock YJ shafts to stronger and simpler XJ shafts, and all modifications and special procedures. This is not meant to be a detailed instruction list, just something to help a fellow jeeper along.


Parts You Will Need
  • TJ or 96+ XJ shafts
  • Dana 30 Driver's side seal
  • Sheet Metal (for cover plate)



1. After chocking the Jeep and getting it on jack stands, remove the tire. Remove the cotter pin with a pair of needle-nose pliers, and make sure you don't misplace the nut retainer in there.

2. Next to come off is the brake caliper. Using a 13 mm socket, remove the two bolts on the back of it. Pull the caliper off, and using a zip tie or something, secure it up and out of the way. Otherwise, lay it in front of the knuckle on the tie rod.

3. Pull the brake rotor off the wheel studs, and lay it out of the way.

4. Now's the time to get out the power tools. You need to remove the axle nut, and its ON there! You can do it with a breaker bar though, but if you have the power tools to do so, then use them. Using a 36 mm six-point socket, back that bolt out. If you don't have one, its something you can pick up at your local auto parts store for $10 or less. Make sure to get one rated for impact wrenches, because you'll be on that sucker. When you put it back on, it is supposed to be torqued down to 175 ft/lbs.

5. After removing the axle nut, There are three bolts on the back of the unit bearing. These are 13 mm twelve point bolts, and are torqued down to 75 ft/lbs. I would use a 1/2" drive set for these, as they are torqued down to a bit more than that. As a side note, leave the keys in the ignition to the first click, so you can turn the tires to get a better angle on the bolts.





6. To remove the stuck bearing, you can use a prybar and a hammer, just be gentle. Small hits in the right places will pull it out easily. When you put it back together, make sure to use anti-seize on the contact portions, it will make it MUCH easier to remove next time.

7. Make a note of how the dust shield goes on, and which side is which (if you're doing both sides simultaneously). Lay that off to the side with the pile of other stuff that you removed.

8. Now its time to take care of the CAD housing. Unplug the vacuum lines from the motor, and plug them with bolts. Tie them up and out of the way for now. The motor is held on with four 11 mm bolts. Make sure that before you start removing that, you have an oil drain container below it to catch the gear oil that comes out. It'll get messy, just a warning. Also, the small skid plate for the cylinder comes off with two 13 mm bolts, but the one on the right needs an angled socket to get to it.

9. Once the housing is out, slide the outer shaft out and remove the collar on the shaft. Pull out the intermediate shaft as well. Remember that prybar? Use it to remove the seal. Its located on the right side of the CAD housing. Mine came out fairly easier than I expected, but then again, I didn't know what to expect.



10. Seating the seal comes next. This is where ingenuity comes in handy. Normally to seat the seal, you have to drive it in from the carrier housing. That means a heck of a lot of work, not fun. What we rigged up is a simple tool that pulled the seal in as we wrenched on it. It consisted of a threaded rod with a nut and large washer (4"+ in diameter) on the knuckle end of it, the seal, a smaller washer (the size of the seal), and a nut (parts going from the outside in). As you would tighten the nut on the outside, it would drive the seal towards the outside, where it needed to be seated. Its hard to describe, check the pictures.




11. Once the seal is seated, you need to make a cover for the motor housing. Easiest way is to take off the seal, trace in on your metal, then cut it out with a sawzall. Drill out all four holes, and use the bolts from the motor housing to rebolt it back on, using RTV to seal it well. Here's a pic of mine.



12. Now, put it all back together! When you slide the new shafts back in, it is recommended you grease the splines and the spot where the seal rides. When you slide the shaft back in, make sure to support it right at the end of the axle tube, to prevent catching the seal.

You will need to fill the differential back up with gear oil, almost all of it will drain out. Look on the bright side, you're doing two jobs at once!

To rehash, the factory torque specs are 175 ft/lbs for the axle nut, and 75 ft/lbs for the unit bearings. The calipers are torqued to 11 ft lbs.

I sure hope this helps anyone who thinks this job is too intimidating.



Brandon

__________________
2004 Jeep WJ Grand Cherokee Overland - My DD
1988 Jeep MJ Comanche 4.0L - Dad's
1999 Jeep WJ Grand Cherokee Limited 4.0L - Mom's

Last edited by H3RTCH; 07-29-2009 at 01:24 PM..
H3RTCH is offline   Reply With Quote Quick reply to this message
Unread 07-28-2009, 12:17 AM   #2
Axl Jack
Registered User
1994 YJ Wrangler 
 
Join Date: Mar 2007
Location: Old Forge, PA (Scranton)
Posts: 2,513
Nice write-up. I have to replace both seals on my D30 this weekend. Would be nice to go with TJ shafts, but I don't have the time or the cash to locate any. My D30 is from a 95, so hopefully I have the larger u-joints anyway. I will find out shortly (as I might as well replace them as well).
__________________
94 YJ w/ stuff. All the work/money I put into it, and the comment I get most is my $20 mod: "Hand throttle?!? That's awesome."
Quote:
Originally Posted by dmcanally View Post
You know you drive a YJ when it is no longer getting older, but slowly becoming brand new part by part.
Axl Jack is offline   Reply With Quote Quick reply to this message
Unread 07-28-2009, 10:30 AM   #3
H3RTCH
Live Free or Die.
 
H3RTCH's Avatar
2004 WJ 
 
Join Date: Jul 2008
Location: Norfolk, VA
Posts: 1,062
Thanks. I would suggest using my method to seat the seal on the passenger side, but you'll have to take the diff out to get the driver's side anyway.

Brandon
__________________
2004 Jeep WJ Grand Cherokee Overland - My DD
1988 Jeep MJ Comanche 4.0L - Dad's
1999 Jeep WJ Grand Cherokee Limited 4.0L - Mom's
H3RTCH is offline   Reply With Quote Quick reply to this message
Unread 07-28-2009, 01:07 PM   #4
timatoe
Registered User
1990 YJ Wrangler 
 
Join Date: Aug 2006
Location: Grass Valley California
Posts: 13,791
It looks like you put a seal in the old CAD unit, is that right? Cause the only seal you need is for the passenger side at the carrier. It's not too tough to pop the carrier out and tap the new seal (Napa 11800) in there with a 1 3/16" socket.
__________________
Quote:
Originally Posted by George Orwell
We sleep safe in our beds because rough men stand ready in the night to visit violence on those who would do us harm.
timatoe is online now   Reply With Quote Quick reply to this message
Unread 07-28-2009, 01:54 PM   #5
H3RTCH
Live Free or Die.
 
H3RTCH's Avatar
2004 WJ 
 
Join Date: Jul 2008
Location: Norfolk, VA
Posts: 1,062
Quote:
Originally Posted by timatoe View Post
It looks like you put a seal in the old CAD unit, is that right? Cause the only seal you need is for the passenger side at the carrier. It's not too tough to pop the carrier out and tap the new seal (Napa 11800) in there with a 1 3/16" socket.
Yea, that's what we did. Being somewhat of a novice to working on my own vehicle, Pulling out the carrier was a very intimidating task, and something I didn't want to do just yet. I didn't know it could be right at the carrier though, I'll have to keep that in mind. Thanks!

Brandon
__________________
2004 Jeep WJ Grand Cherokee Overland - My DD
1988 Jeep MJ Comanche 4.0L - Dad's
1999 Jeep WJ Grand Cherokee Limited 4.0L - Mom's
H3RTCH is offline   Reply With Quote Quick reply to this message
Unread 07-28-2009, 04:18 PM   #6
Tony89
Registered User
1998 XJ Cherokee 
 
Join Date: Jul 2008
Location: Baton Rouge, LA
Posts: 572
Quote:
Originally Posted by Smithy View Post
Yea, that's what we did. Being somewhat of a novice to working on my own vehicle, Pulling out the carrier was a very intimidating task, and something I didn't want to do just yet. I didn't know it could be right at the carrier though, I'll have to keep that in mind. Thanks!

Brandon
I think the problem is that the TJ axles aren't machined for a seal at the CAD (cuz the TJ doesn't have one duh) so the axle will quickly tear up the seal and then you'll have a leak.
__________________
98 XJ - 4.5" Lift, 32" BFGs, Lots other stuff
Tony89 is offline   Reply With Quote Quick reply to this message
Unread 07-28-2009, 04:25 PM   #7
H3RTCH
Live Free or Die.
 
H3RTCH's Avatar
2004 WJ 
 
Join Date: Jul 2008
Location: Norfolk, VA
Posts: 1,062
Quote:
Originally Posted by Tony89 View Post
I think the problem is that the TJ axles aren't machined for a seal at the CAD (cuz the TJ doesn't have one duh) so the axle will quickly tear up the seal and then you'll have a leak.
Good point, but I know someone who did the same thing as I did and hasn't had any issues. Its his DD as well. We'll see what happens.

Brandon
__________________
2004 Jeep WJ Grand Cherokee Overland - My DD
1988 Jeep MJ Comanche 4.0L - Dad's
1999 Jeep WJ Grand Cherokee Limited 4.0L - Mom's
H3RTCH is offline   Reply With Quote Quick reply to this message
Unread 07-28-2009, 04:56 PM   #8
Axl Jack
Registered User
1994 YJ Wrangler 
 
Join Date: Mar 2007
Location: Old Forge, PA (Scranton)
Posts: 2,513
Quote:
Originally Posted by Tony89 View Post
I think the problem is that the TJ axles aren't machined for a seal at the CAD (cuz the TJ doesn't have one duh) so the axle will quickly tear up the seal and then you'll have a leak.
Yeah I heard somebody mention that before. I think I remember JeeperDon talking about it. He said you have to do something special in order to seal it correctly. Can't remember what that was for the life of me though. Maybe he'll read this and reply.
__________________
94 YJ w/ stuff. All the work/money I put into it, and the comment I get most is my $20 mod: "Hand throttle?!? That's awesome."
Quote:
Originally Posted by dmcanally View Post
You know you drive a YJ when it is no longer getting older, but slowly becoming brand new part by part.
Axl Jack is offline   Reply With Quote Quick reply to this message
Unread 07-29-2009, 01:47 AM   #9
timatoe
Registered User
1990 YJ Wrangler 
 
Join Date: Aug 2006
Location: Grass Valley California
Posts: 13,791
Quote:
Originally Posted by Axl Jack View Post
Yeah I heard somebody mention that before. I think I remember JeeperDon talking about it. He said you have to do something special in order to seal it correctly. Can't remember what that was for the life of me though. Maybe he'll read this and reply.
Seal it at the diff, the other seal will eventually leak. Most don't put one at the CAD at all anymore.
__________________
Quote:
Originally Posted by George Orwell
We sleep safe in our beds because rough men stand ready in the night to visit violence on those who would do us harm.
timatoe is online now   Reply With Quote Quick reply to this message
Unread 07-29-2009, 07:47 AM   #10
drunkencitywork
Registered User
1995 YJ Wrangler 
 
Join Date: Mar 2009
Location: southside chicago
Posts: 137
1-i wouldnt use loctight. I used antisieze. 2- 1/2"12point works for 3hub bolt 3- national part number 471763 taps right in for seal at housing. Just did mine and locrite. Trailtested.worked great
__________________
95yj2.5auto-4"sua-305/70bfg mt on rubi's-4.0tb-frnt tube fenders-frnt&rear fabbed bumps w tire swing-8.8lsd disc-shortened xj soon cage,rockers,diff covers
drunkencitywork is offline   Reply With Quote Quick reply to this message
Unread 08-20-2009, 01:35 PM   #11
brower
Registered User
1993 YJ Wrangler 
 
Join Date: Jun 2009
Location: usa
Posts: 33
just wondering if your gas mileage changed at all? i would think a drop of 1-2mpg
brower is offline   Reply With Quote Quick reply to this message
Unread 02-15-2010, 05:37 PM   #12
NHfireLJ
Jeeper Creeper
 
NHfireLJ's Avatar
2005 LJ Wrangler 
 
Join Date: Dec 2009
Location: Seacoast NH
Posts: 2,655
On the TJ axle conversion...Do you HAVE to replace both sides? Or can I just to the passenger side?

Less money, less time, less seals...

Yes/No?
NHfireLJ is offline   Reply With Quote Quick reply to this message
Unread 02-15-2010, 07:41 PM   #13
timatoe
Registered User
1990 YJ Wrangler 
 
Join Date: Aug 2006
Location: Grass Valley California
Posts: 13,791
Quote:
Originally Posted by Fire1kubota View Post
On the TJ axle conversion...Do you HAVE to replace both sides? Or can I just to the passenger side?

Less money, less time, less seals...

Yes/No?
No, there is already a seal at the diff on the driver side. If it's in bad shape it would be a good idea to replace it. I left mine alone and only put the Napa 11800 into the passenger side of the diff.
__________________
Quote:
Originally Posted by George Orwell
We sleep safe in our beds because rough men stand ready in the night to visit violence on those who would do us harm.
timatoe is online now   Reply With Quote Quick reply to this message
Unread 02-15-2010, 07:50 PM   #14
simpkijd
Registered User
2012 JK Wrangler 
 
Join Date: Mar 2007
Location: Chester, VA
Posts: 84
I'm in the middle of doing this upgrade right now. Let me know anyone has a picture request or question and I'll try help. Everything tore apart now but start reassembly on Wednesday.
__________________
One day my Jeep will be .....

[url]http://southsidejeepers.freeforums.org/[/url]

[url]http://www.militaryjeepers.com/[/url]
simpkijd is offline   Reply With Quote Quick reply to this message
Unread 02-15-2010, 08:35 PM   #15
NHfireLJ
Jeeper Creeper
 
NHfireLJ's Avatar
2005 LJ Wrangler 
 
Join Date: Dec 2009
Location: Seacoast NH
Posts: 2,655
I think you missed my question..it really wasn't about the seals, but the shafts....

can I just replace the passenger shaft? and not the driverside...

Thanks
NHfireLJ is offline   Reply With Quote Quick reply to this message
Reply

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the JeepForum.com forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid e-mail address for yourself.
Note: All free e-mails have been banned due to mis-use. (Yahoo, Gmail, Hotmail, etc.)
Don't have a non-free e-mail address? Click here for a solution: Manual Account Creation
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.


Thread Tools


Suggested Threads





Jeep, Wrangler, Cherokee, Grand Cherokee, and other models are copyrighted and trademarked to Jeep/Chrysler Corporation. JeepForum.com is not in any way associated with Jeep or the Chrysler Corp.