Rear end

If you can get over to Cat motor shop they can put it on dino. and run a cutout test at rpm that its acting up at to find the inj. that is still under warnt. from over/haul last year?

 

Tech should be able to plug the laptop in and run a cylinder cut-out test with you driving, under various load (or bobtail), going down the road - at least, Cummins shop did this for me.

Rear end problems I have little experience in, aside from jacking the rear up stationary and running it/examining for trouble.

good luck.

 

Re shimming the input shaft is not that hard. It's right there in the manual on how to do it. The only special tool you need is a dial indicator. it took me 3 tries before I got mine right. It was in fact one of the many vibrations I was trying to fix. Not sure that the symptoms your describing fit that though?

I do encourage you to get it tight though. Your days are numbered if you can feel and see the play on that input shaft.

 

Ride height?

 

I had a similar concern last summer on my 04 with 1.1 million miles. Symptoms a bit different, thought I could hear/feel a grinding sometimes. Front diff and pd had been replaced, rear as far as I knew was original. I decided to pull oil samples. Front was good, rear came back with off the page (dpq, dpi, ? something like that, means suspended metal particles). So I changed oil, pulled more samples, same result. Like you, last thing I need is an on the road breakdown, so I sent it to the shop for a replacement. When I picked up the old one to take back for core, all the surfaces were covered with small particles of metal, about the size of the head of a pin. Something was starting to come apart, maybe bearings? Everything I could see as far as gear surfaces looked fine, it was from somewhere you couldn't see. So I think I did the right thing. You might want to pull oil samples. That should help you to know whats going on. Minor cost could prevent catastrophic breakdown before it happens.

 

He don' t need oil samples when your plug is full metal shavings. Mud on the plug is normal, but chunks, filings, shavings your done.
That' Is about all a guy needs to see to make up ones mind to replace..
At least it would be mine.

Those old 40,000 eatons eat 2 power dividers in there usefull lifetime I found. By then the whole third member will be shot. The carrier bearings are a week point on those.

 

I have Eaton rears. These symptoms sound exactly like mine when the power divider crapped out several years ago.

 

I’m having the same problem. Just replaced my front diff after it tore up on 75 and on the way from the shop I still felt the vibration again. Did you end up replacing your rear rear?