Jack up the rig, and support it with stands. You don’t want it falling on you! Again, since I’m just changing carriers, I’m not replacing gears. So some of these install pictures will be of the Dana 44. That way you can get the full effect and not be cheated out of a good how-to.
Drain the fluid – Remove all of the bolts but the top one. That way you aren’t fighting the cover as well as making sure the oil is going in the bucket.
While that’s draining, go ahead and remove your brakes and pull the shafts out a little bit – this axle is a full floating axle and removing the brakes isn’t necessary, like it would be on a semi-float unit. On some other axles, like the semi-float Dana 60, 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 it’s 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!
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 don’t want it to fall!
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.
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 isn’t going to tell you much, so we’ll read the coast side.
Drive side: - it actually looks deep and not shallow. Again, ignore.
Check your backlash, too. This one was .030”! He did say it was starting to make a clunking noise.
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.
Now grab hold and pull the carrier out. This one in the Dana 44 came out very easy, as it had no preload on it. I really didn’t need the bar’s help… Carrier preload is your friend! More on that later, during the install. Sometimes it’s 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.
Carrier is out!
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, do yourself a favor and just replace them.
On some axles, there will be a RTV made ‘o ring’ 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…
It’s out, and in one piece with very little to no clean up.
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.
Now put a rag over the pinion head and drill a 7/16” hole for the bulkhead fitting.
Now tap the hole to ¼” pipe.
On the bulkhead fitting, I use a little bit of Teflon tape – note, it’s yellow and not white!
The cover says blah, blah, blah and works when it comes in contact with oil, propane, and etc.
Screw the bulkhead fitting in and snug it up.
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 won’t cycle once. Oh, put a rag over the pinion again.
Tada! It’s about a ¼” groove is all. Just enough to drain the axle tube and allow the upper hole to be used as a vent.
I’ll 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 it everything will be clean and there won’t be any chances for metal to get inside your shim pack or bearings.
Doh! Thick gears.. We won’t be re-using these…
Time to remove the old pinion and clean up the housing, getting it ready for new bearings, etc.
Start off with all the same shims everywhere as what was already in there. Chances are I’ll have to add some – if you recall, the pinion was too shallow before. I don’t put the pinion seal in at this time (or crush sleeve if it’s used instead of shims) and I also just use a standard nut, not the top lock style. Also, put a little bit of gear oil on the threads and keep them nicely lubed, so the nut doesn’t destroy the threads and leave you with a junk gear set! 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.