YUKON ZIP LOCKER INSTALL
By Wayne Hartwig - www.alljeep.com
The Yukon Zip Locker is a new to the market air actuated locker and contains forged 4320 side gears. This locker is going into a Jeep Cherokee Dana 44 rear end. Iím going to cover everything from start to finish as well as go inside the locker to show you what they look like. Iím also going to be using my 2 car garage to show that with the proper tools, you can install this yourself. Everyoneís gotta learn at some time, right? And if you are one of those guys that working on his own rig is a requirement, then here you go! Of course, if youíre the other kind of guy that just doesnít have the patience or correct tools, your local off-road shop can install them as well. While this is not difficult work, it does require some patience and precision.
1-Received the Zip Locker from Yukon. Like everything else Iíve received from them, it was well packaged. Even though the locker comes in its own packaging, Yukon will package that package inside of another box with material to keep everything safe and looking nice when it arrives. (Sorry, no picture of this - I should have looking back, but at the time I didnít think about it...)
2-Hereís the box:
3-Open it up and the first thing you see are the carrier bearings, shims and seal housing.
4-Pull the Ďcardí out of the way, and there are some directions and stickers.
5-Hereís what the directions look like.
6-And the sticker.
7-And the Yukon Zip Locker, air hose, and baggy of small parts.
8-Hereís the air line.
9-Baggy of parts - solenoid, switch, switch cover, zip ties, o-rings, bulkhead and other various fittings.
10-Introducing the new air actuated Yukon Zip Locker!
You can see the Yukon ĎYí in this picture
11-Time to go inside and take a look! Remove the two socket head cap screws and the flange cap comes off. You can see a thrust washer and the side gear now.
12-Hereís what the side gears look like. Nice, smooth finish and made of forged 4320.
13-Hereís the pinion gears - note, there are 4 pinions! The long cross shaft is also secured on both ends, not just one end. Those that have busted cross shafts in other lockerís, know that the one pin will no longer keep it secure, and will cause the cross shaft to whip around and destroy everything in the differential. With dual pins holding the cross shaft in place, that potential problem is long gone.
14-There are 8 - 8mm, 12.9 grade cylinder cap bolts hold the cylinder cap in place. Not only is there a lock washer in place, but lots of red loctite as well. These are torque to yield and need to be replaced if you ever take them out.
15-To the left, inside of the cylinder cap, you can see the bonded seal and another side gear thrust washer. To the right you can see the side gear and top of the piston.
Just a close up of the cylinder cap and etc.
And a close up of the side gear and etc. You can also make out the 4 cross shaft retaining pins.
16-Remove the 4 cross shaft retaining pins.
17-And the three cross shafts. The long one holds two pinion gears in place, while the two smaller cross shafts hold one pinion gear each.
18-Hereís what the pinion gears and pinion gear thrust washers look like. All 4 of them look identical and have the same part number on them as well.
19-Hereís the spider block.
20-And finally just a few pictures of the piston and cylinder assembly.
There it is! Itís very simple to tear down and replace parts if there ever becomes an issue or even just for inspection. On to the install....
1-Jack up the rig, and support it with stands. You donít want it falling on you! Guess Iím starting to go bald, huh?
2-Drain the fluid - Remove all of the bolts but the top one. That way you arenít fighting the cover as well as making sure the oil is going in the bucket.
3-While thatís draining, go ahead and remove your brakes and pull the shafts out a little bit. On some other axles, like Dana 35ís, the seal is in the housing and by resting the shaft on the seal part way out like this, you chance damaging the seal. So itís best to go ahead and just pull the shaft all the way out instead. Some oil is going to come out with the shaft, so have a couple of buckets there to catch it!
4-Time to unhook the driveline and tie it up and out of the way somewhere. This time I just sat it up on top of the muffler and tie wrapped it in place, just to keep it there. If it falls off, it might knock you out or if it drops far enough, it could damage the CV ball in the dual cardan joint. Either way, you donít want it to fall!
5-Now it should be drained. Go ahead and pull the cover off completely and set it off to the side to be cleaned and reused later.
6-Before tearing into it, take some gear marking compound and check the pattern. This one is too shallow. Since they are used gears, the drive side isnít going to tell you much, so weíll read the coast side.
Drive side: - it actually looks deep and not shallow. Again, ignore.
7-Check your backlash, too. This one was .030"! He did say it was starting to make a clunking noise.
8-Before you pull off the carrier cap caps, make sure they are marked for orientation. Most of them will have a standard H and a lazy H on the cap and just to the side in the gasket surface to match - sometimes it can be a B or M or whatever they used that day and not just a H. If they are not marked, make sure you mark them in a fashion that will easily allow you to know where they came from later. Personally, I take a punch and will put 1 dot on one cap and gasket surface and 2 dots on the other. Put them on the upper half of the cap, that way you can also quickly know which end is up. These were marked from the factory.
9-Now grab hold and pull the carrier out. This one came out very easy, as it had no preload on it. I really didnít need the barís help... Carrier preload is your friend! More on that later, during the install. Sometimes itís difficult and a case spreader is used. Just remember, if you do use a spreader and after you get the differential out, remove the pressure on the spreader. The spreader should only be used in temporary situations for a quick amount of time and NEVER on aluminum housings.
10-Carrier is out!
11-Time to buzz off the ring gear bolts. I personally do not reuse them. They are cheap, and do stretch. If they stretch, they will become loose. Red loctite only works so well. IE Cheap insurance, replace them.
12-On some axles, there will be a RTV made Ďo ringí between the carrier bearings and the housing. I take them out if they are there. A screwdriver makes short work of it - just rub it around the edges and viola...
Itís out, and in one piece with very little to no clean up.
13-Time to just clean it up a bit with brake kleen. It makes it easier to clean up the metal junk later if you get rid of some of the gear oil now.
14-Now put a rag over the pinion head and drill a 7/16" hole for the bulkhead fitting.
15-Now tap the hole to ľ" pipe.
16-On the bulkhead fitting, I use a little bit of Teflon tape - note, itís yellow and not white!
The cover says blah, blah, blah and works when it comes in contact with oil, propane, and etc.
17-Screw the bulkhead fitting in and snug it up.
18-On some diffs there is not a drain hole to drain the oil in the tube and must be added. The problem is there is only one hole up on top and what happens is the oil will trap the air and can cause the wheel seals to leak and etc. Just put the drain hole on the same side as the breather hose. I like to use a Roto Zip, instead of die grinder. Less air to blow the shavings around and the best part is your compressor wonít cycle once. Oh, put a rag over the pinion again.
Tada! Itís about a ľ" groove is all. Just enough to drain the axle tube and allow the upper hole to be used as a vent.
19-Iíll use a grinder to clean up the gasket surface. On off-road rigs, the gasket surface will usually have burrs from being drug over rocks. This will clean that up so the gasket will have a better chance of sealing later.
All cleaned up and ready for re-assembly! Do all of the work first, then when you install the Zip Locker everything will be clean and there wonít be any chances for metal to get inside your shim pack or bearings!
20-Doh! Thick gears.. We wonít be re-using these...
21-Time to remove the old pinion and clean up the housing, getting it ready for new bearings, etc.
22-Start off with all the same shims everywhere as what was already in there. Chances are Iíll have to add some - if you recall, the pinion was too shallow before. I donít put the pinion seal in at this time (or crush sleeve if itís used instead of shims) and I also just use a standard nut, not the top lock style. I also use a setup race that you can easily make with a grinder or sand paper. Basically you want to take a few thou off either the inner or outer surface to allow it to quickly/easily be removed for shim changes.
23-Before installing the ring gear, you should always file both surfaces to make sure they are flat and there are no burrs.
24-New ring gear bolts with red loctite on them, evenly torqued in stages and a criss cross pattern. Some use a vice to hold the carrier while you do this, I like to use the press.
25-Time to press on the bearings. With your finger, wipe a little bit of CLEAN gear oil on the bore of the bearing to help while you press it on.
26-Time to prep the seal housing for o rings. I like to put a little bit of oil in the grooves first. I think it allows the o rings to go in easier without being twisted - you donít want them to twist or they will leak/tear/wear unevenly.
O-rings are in!
27-Put the carrier back in with some shims so that itís nice and snug and to spec on backlash. In this case .008", perfect!
Iíll also check my pinion preload for giggles. If it has a crush sleeve instead of shims, Iíll use about 10 inch lbs to check the pattern. There is 10 inch lbs on it right now.
28-Now we can check our patterns. I measured the original pinion shim pack and made a new one with the same thickness. Like before, too shallow.
Even the pinion has an opinion, and it agrees - too shallow:
29-Pull the pinion back out and add .003" behind the inner pinion bearing race. Again, make sure the backlash is correct before checking your pattern again. Perfect!
30-Now that the pinion depth is set correctly, Iíll set the new race and check pinion preload. Itís kind of hard to take a picture and keep rotating the pinion - measure the preload on a fast rotating pinion, not the start load required to get it turning. This one has 16 inches of preload - perfect! Spec is 14-19 inches. For each .001" of change on the shim pack, you can expect a 5-6 inch change in preload.
Again, do all of this without the pinion seal in place. Donít want to skew the numbers! Just use a little bit of gear oil on the bearings to reduce dry rolling friction, if there is any.
31-Now that all of thatís done, time for the slinger and pinion seal. Iíll pack the backside of the pinion seal with grease to keep the spring from possibly falling off while tapping it in place. Iíll also put on some aviation gasket sinch sealer stuff - the brown Permatex, in the white bottle with the brush on top. Just a little more assurance against leaks.
On the Dana 44 axle, the inner pinion bearing race fits perfect!
Tada! Undamaged seal!
32-Now that the seal is in, Iíll tighten everything up one last time with the standard nut. Then I take that nut off, clean the pinion threads, use some red loctite and put the new pinion nut in place.
33-Time to put the carrier back in for the last time. Hereís where you set your carrier preload. For me, carrier preload is very important and Iíll use a lot - especially with a spool or locker setup. Itís also time to run the seal housing tube through the bulkhead fitting. There are a lot of ways to do this. Whichever way you choose, make sure the copper tubing does not come into contact with any part of the differential, housing, or diff cover. If it does, it can vibrate and rub a hole through it, causing an air leak. Personally, I like to run mine up through the top, which rarely needs a modified carrier cap, and also will never interfere with any of the diff covers on the market.
There it is! All done and ready to test. My overall impression of the Yukon Zip Locker is very good. They appear to be built right, with a lot of thought in the design and with the quality parts that make up the locker, it should work great for many years to come!
Randy's Ring & Pinion
10411 Airport Road SE
Everett , WA 98204
4605 E Bixel CT
Mead, WA 99021