Dana 41 Issues - need help

[LKap]

I did a partial rebuild of my rear axle a few years ago when I got my 3a. At the time it was running fine but leaking from both hubs and the pinion yoke. It also needed new brakes. While I had the hubs off for the brake job I figured I'd put new axle bearings in too. I used the same shims, replaced the outer seals and put it back together. I also took the yoke off and replaced the pinion seal. Initially everything was fine. About a year ago I started to get an intermittent "clunk" from the rear end when starting or going from reverse to forward. It has gotten progressively worse and now happens routinely when starting after stopping at a red light.  I figured it was an issue with the differential so I just opened it up and everything looks "ok". I don't have a dial indicator to measure the backlash but it is just a slight click. Could I have overtightened the yoke messing up the backlash? Could it be worn carrier and/or pinion bearings?  I think the issue might be the spider gears??. With the rear jacked up I can turn one wheel hub 10-15 degrees befor the spider gears move and this is accompanied by a decent click. There is also a small area of metal wear on the spacer where it rubs on the cross-shaft (see pic) Is this normal? The last time I had the axles out they did not appear worn at all.  Before I replace all the bearings and cross my fingers that works I'd welcome any advice

[aboyandhisdog]

I don't think you mentioned having checked the U-joints.  That kind of sounds like a worn u-joint to me.  Just throwing out ideas.  Might be less serious than you think with a bit of luck.

[LKap]

I admit to being a shade tree mechanic. I have enough knowledge to be dangerous!! U joints were all replaced recently. I have been contemplating this issue for awhile and I’m definite the it’s somewhere in the diff. I have never rebuilt a differential and the thought of reshiming everything from scratch scares me. Hoping there’s an easy way out

[oldtime]

Put transfer case in neutral.
Grab rear D41 input yoke.
Turn it back and forth by hand.
How much play does it have ?...meaning how far does it rotate back and forth?

[LKap]

The rear driveshaft is disconnected. There is minimal play with rotation of the yolk. Maybe 2-3 degrees with a slight click. I think the backlash is ok.  The major amount of play is when I try to rotate the hubs/drums. With this there is major play In The axles and spider gears

[oldtime]

Great that’s the ideal way to estimate gear backlash with propeller shaft removed .
Ideally there will be about 1/8” of back/forth travel noted at the outer edge of the yoke.
More yoke free play motion than 1/4” suggests it will need bearings very soon.
If it passes that test then your excess wheel motion must be either the axle splines or the pinion mate gears which drive the axle shafts.

[OnlyOneDR]

Are the ring gear bolts tight?  Dana 41s like to work theirs loose.

[LKap]

Ring gear is tight. All the lock tabs are intact too. I’ll try to pull the shafts when I get home from work tonight and get some pics of the splines. How much play is there supposed to be in the spacer shaft with the axles out?

[oldtime]

Not likely much play at the axle shaft splines.
The centerblock spacer normally has nearly 1/4” of side motion.
Maybe the hub is not tightly keyed to the axle shaft ?

[Rus Curtis]

Hard to follow this thread as 4 posts show blank.  Apologies if I'm repeating since I can't tell.

I had excessive clearance, from the Service Manual, in my D41 side gears.  I couldn't find shims from any vendor so I had some made locally.  I hired out to have the pinion re-installed after the first garage unnecessarily tore it down - and damaged one of the cone washers on a spider gear too (had to replace those also).

I would have suspected the U joint also.

[Oilleaker1]

I just went through everything you mentioned but with my dana 44. I had a annoying clunk when changing from forward to reverse. The axle splines were fine, back lash was fine, and the ring was tight. I decided to pull the case out and look closer. I removed the two case retainers and prepared to either spread the differential housing or slide hammer the case out. It almost fell out!!!!!!! The passenger side bearing on the case came off with my hand and the bearing shims were smashed looking which led me to believe the case was shifting side to side. I though that was it------------wrong. Look carefully at the side gear shims inside. One had the shim hanging out which rotated with the side gear and actually hit the case housing. The center of the shim had become enlarged and was shifting side to side. It had been hot too. So, new bearings and cups, new side gear shims, and all is now quiet and fine. I bought a shim kit from Ron Fitzpatrick and located side gear shims at my local transmission shop. I measured all the originals and replaced them with the same size/thickness shims. i sure hated that clunk. Drove me mad. When the clunk happened the nose of the pinion and yoke would shift up and down with the noise while my wife drove it forward and back . Crazy. All fixed now. John

[LKap]

I got it all disassembled today.  Carrier popped out pretty easy.  Carrier bearings looked ok but based on how easy it came out, they must have some wear. The pinion bearing was definitely worn out.  I'm making a shopping list right now - new bearings, races, seals and all new shims.  Ring and pinion gears look ok so I'm not going to change them. Anything else I should do while the diff is completely torn apart?

[Rus Curtis]

There is guidance in the Service Manual about checking the side gears.  That would be a good idea.

[LKap]

Checked the side gears. I have 0.003 gap. Manual says up to 0.006 is good. Order submitted to Walcks for all the new bearings, etc. I’ll update once it’s all back together.

[LKap]

Parts arrived yesterday. The carrier is set up and ready to install but I’m struggling with the pinion. The inner and outer races went in fine. Used the same size shims under the inner race. I put the same thickness of shims on the shoulder of the pinion shaft and installed. Tightened the outer bearing down with the yolk in place using a impact. It was very tight and I could barely turn the yolk. Obviously WAY more than the recommended 10-25 inch-pounds in the manual.  Could I have over tightened it? Is that possible with the same thickness of shims? I backed the pinion nut off and gave the shaft a couple solid whacks with a punch and it loosened up to what feels about right. Not sure this is good though. Need advice