D44 Problems

Hey guys,

Its been a long time since I've been at the 3A. Life got in the way, as they say, but I'm back at it.

When I stopped working on it, I had the 44 up on the bench. I replaced the carrier bearings, pinion bearing and seal and the outer axle bearings and seals. When I was done re-assembling the carrier and pinion into the housing, it had a little more play that I was comfortable with. You could turn the yoke maybe 1/8" before the pinion would engage the ring gear. I smeared some grease on the ring gear to check the contact pattern, and it looked like I just needed to move some shims to the other side of the carrier and I'd be good, pinion depth looked fine to me. Then it sat on the bench for about 3 years.

I pulled it apart today and with the help of a bearing splitter/puller I yanked the bearings off the carrier and swapped one thick shim on one side for one thin one on the other side, and thought that would do it. I drove the bearings back onto the carrier, and re-assembled everything. When I tightened down the bearing caps, the whole assembly was locked up solid. I needed the length of my pry bar through the yoke to get it to turn. It also turned uneven, some spots seemed to turn easier than others. I determined that the tighter the caps, the harder it was to turn, so I figured that the pinion was set too deep. I pulled that out, took a couple shims off the pinion shaft, and again re-assembled everything. No change. Its waaay too tight.

I determined at least one thing, that the bearing splitter boogered up the cage on the carrier bearing, and deformed it a bit. I figure thats the cause of the uneven resistance when I turn the yoke. So I'll probably need to grab a few new cones. Thats my story, I have two questions.

First, what do you guys recommend for pulling the bearings off the carrier without wrecking the bearing cage? It sounds like I'll need to some experimenting with shims, and I don't really want to have to buy a new one each time I pull one off.

Second, why is this thing so freaking tight? Looking at the contact pattern in the grease, it looks like I only have about 1/2 to 3/4 of tooth contact between the ring gear and pinion gear, so what gives? Can the pinion depth be off that much?

Any light any of you pros can shed would be greatly appreciated. Thanks guys!

 

What you really need is a differential bearing puller, but setup bearings work as well. The depth and backlash both change as the ring gear is moved side to side. Well, technically the pinion depth is the same, but the contact point with the ring gear moves as the ring gear moves in. If this was just an R&R to get new bearings then depth should be right and side shims changed to fix. But if you did a new R&P or moved shims around, then it may be a slow process. You can get a universal pinion depth checker from under $100 and if you have an aftermarket gear set with a marked pinion depth (or even OEM) might be the fastest way to get you in the ballpark. You can read about this over at Pirate:

http://www.pirate4x4.com/tech/billavista/PR-ARB/articles/Randys_Carrier_Bearing_Puller_Review/

 

sounds like you need a micrometer as well to measure those shims
just moving "thick and thin" shims around isn't going to cut it...
maybe you should get a set of set-up bearings as well, bearings that will slide on easily while you're doing the set-up
I've seen a few old timers with lots of years experience set-up axles by hand/feel
for newbies or the inexperienced, get the right tools to do the job correctly.

 

Thanks for the advice guys...I hadn't thought of using set up gears to get the shims right. Just grind a little off the ID of an old bearing? I have a micrometer, though I don't have anything to measure the backlash with, so knowing the thickness of the shims wont help me much, its going to have to be a feel/sight thing on this one. I'm going to put the shims back to where they were and see where I am at that point. I knew I should have just left it alone...

 

Now that I'm rethinking things already, I should at least make sure that the pre-load is right. Its .015 for the carrier bearing pre-load, right?

 

As noted above, the ring & gears backlash is not affected by the differential gears, but the driveline lash is which is one thing that mechanical lockers impart differently to the mix.

You can get an inexpensive dial caliper for about $15 to measure shim thickness. The only way to measure for side bearing preload is with a dial indicator and use a housing spreader. But even that is not 100% accuracte because you are only measuring the amount the spreader moved in relation to the indicator and figure some stretch on the opposite side of the indicator as well.. To some extent, setting side bearing preload is a best-guess scenario.

After you have put a few together you start to get a resonable "feel" for pinion preload as well as side gear bearing preload.

If you are not planning on doing more differential work, you may want to find a professional to get the gears setup and then you can finish assembling the rest of it. What part of the country are you in? Somebody local to you may be able to help.

 

Finally got the 44 set up to where I'm reasonably satisfied. There is still some amount of play in the spiders, but it was time to get it put together and taken off my bench. Next up is the D27, and hopefully in a few weeks I'll have a rolling chassis again, and I can start measuring for the 225 that I finally got knocked apart last week.