Front Diff question (1 Viewer)

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Well thanks for pointing that out, and I currently am mostly driving on the pavement and some country dirt roads. This is my daily driver and I can't be wheeling it hard and risking breaking things. I wouldn't to that with this truck even if I had a new truck as a daily driver. I've driven this truck for 24 years and plan to have it still running and in good condition in another 24 years. I know what it is capable of as well as my own driving skills so I don't feel I have to prove it by beating it up on the weekends. If that's what I wanted to do, I would buy another 80 and prep it for that type of use primarily. Turns out, aside from the metal shavings in the front diff and the axle seals failing after only 30K (front and rear axles rebuilt along with new brake calipers rotors and 100 series pads and more was done with the motor rebuild), but I don't know if i mentioned earlier in my post because I have been hyper focused on the Diff oil contamination and metal partitals, but I did discover that my DS front wheel bearings had a little slack and needed to be readjusted. Not sure how long it was loose but the spindle shows that the rear wheel bearing race was spinning on the spindle and caused a lot of heat on the front and back sides. That may have contributed and started a chain reaction of failures in the spindle bushing, birfield heating up more and allowing grease to enter the axle housing as it cools and diff oil getting back into the birf. I was told that because I am running 35's, I should be servicing the wheel bearings at least every 30K, re-pack and set preload. I notice also the dust cover and seal is wet too. I guess I should replace this spindle with a new one with the bushing already installed. The other side is fine and that wheel never loosened up.View attachment 2660698

That spindle is not great, but not horrible either.
You could clean it up with some fine emery cloth tape and run it.
I've run with a lot worse without issues.

Do some reading about setting wheel bearing preload. With big tyres, this becomes a critical adjustment for these vehicles. The FSM preloaded method is not reliable.

30k service interval for bearings is ok. Service may consist of jacking up a wheel, checking for play, and remove drive flanges to check condition of grease.

Some of the noises you describe sound consistent with loose wheel bearings.

Growling on deceleration is a typical symptom for dry or worn uni joints.


I also agree with other comments that replacing R&P without draining and refreshing diff oil a couple of times sounds premature.
 
Agreed. That spindle doesn't look like it's the cause of your issue to me. I suspect who ever built your front axle last did a pretty sloppy job. Find a specialist, or do it yourself and then you absolutely know it's been done right
 
Well at this point I don't think I am going to continue with the DIFF as its been drained and refilled and about 500 miles, the level is still where I left it and it still looks good. I will drain again soon and see what it looks like and it there are more shavings on the magnet plug. I think what I am experiencing is the inner bushing on that spindle. I already have a cart built at Cruiser Outfitters with the parts I will need and I've included new wheel bearings and seal and axle seals. I think the other side is ok but will service that as well and inspect everything and repack if its all ok. Ive already talked to Kurt about what I might need. I will keep this thread posted as I continue finding the solution.
 
I drained the front diff now after about 800 miles. Still looks like it’s mixing with the birf grease but I already know the seals need to be changed. I took pictures of the magnet plug and not as bad as before but still has metal particles. Based on this, I’m going to just rebuild the birfields and install new axle seals, new internal bushing on spindle and going to put new wheel bearings both sides. I will then see if the problems is gone and just wait on checking the gears.
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You have to go in pretty deep to pull the axle shafts so that the diff can be removed. If you suspect work on the diff in the future wait and do the knuckle/bearing service and the diff. at the same time to save yourself a few hours of work overall.
 
I agree with @Grandlooser . You've got something bigger going on there if that's after 800 miles. That's NOT coming from the birfs or wheel bearings.

Most likely pinion bearings. Get it sorted sooner than later.
 
Well I do know that the knocking noise and feeling is most likely the birf stub axle on the bushing in the spindle. If it hasn’t already beaten the bushing out and damaged the surface on the shaft, I will get that taken care of first. Then if the diff has issues, I will be able to hear that hopefully. If so, I will just pull the third number and take it to the diff shop so they can inspect everything.
I also just drained the rear diff with 30k (both front and rear done together with 4:88) and the fluid still had the brown translucent look as it drained. This is the plug from the back. The gears had 600 miles breakin with fluid change and then 30k put on them. I think the back plug hopefully is normal but it did have a thicker sludge looking stuff on it.
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