I realize there are multiple threads on this topic, most of them understandably don't provide a whole lot of guidance because the list of potential causes/solutions are long. The problem I am facing is that on deceleration I get a grinding/rumble from the front of the 80, generally happens between 50->40mph, then again from 30->20mph. Has progressively been getting worse across the MPH, randomly will get an audible grind while turning on occasion (may not be related). Also not sure if it is related, but I get some bad rattling under the vehicle when going over rough terrain at low speeds, sounds also like it is coming from the front axle, but very well could be another issue I need to track down.
- Car info - 1997, OEM front and rear lockers, 149K on the odometer, no lift (stock height Dobinsons front and rear), 33" tires
- Purchased the car a year ago, was said to have a full rebuild/service on the knuckles including axle shafts, birfs, seals, and bearings.
- After first road trip notice grinding noise on deceleration and inspect front housings - seals were already busted and apparently axle shafts were not properly installed (and were cheap parts geek $95 units). Lots of metallic shavings in passenger side dues to birf rubbing the housing. I thought this was the main source of my grinding, luckily I caught it before full blowout.
- Replaced axle shafts with OEM, Fuji Birfs, new oem seals, and Koyo bearings just to be safe. Inspected spindles, they were worn past my comfort level so I ordered and installed replacements.
- Take out for a drive, still hearing a grinding noise, but slightly different than the metal-on-metal I was hearing previously.
- Do some research here, find that it could be new spindle bearings if they are not greased properly on installation. Pull them apart, regrease, test again - still present
- I think I may have ruined them by not greasing properly on initial installation. Pull them and install old brass bushings from originals (which were in surprisingly good shape), also just to further isolate the problem - still present
- Somewhere in the middle of this as also installed had new u-joints installed thinking it could be from warn out needle bearings - still present
- Greased everything I could possibly grease under the car and still present
- Bought a chassis ear to see if I can further diagnose - hooked up to each end of the front axle, the end of the front differential, and the front and rear of the transfer case. No noises at the transfer case, audible on the front axle and differential. I can upload a video of the noise if needed, it isn't the easiest to hear but I have it.
- Have changed the Diff oil 3 times this year, no noticeable shavings or discoloration of the fluid
- I plan to take it out again and put the leads on the left, right and rear of the diff to further isolate.
- Is there anything else I need to look at or should be considering?
- If it is the diff, is there anything that can be DIY that I can check before I end up bringing it in to the dealership?
- I looked at Zuks site and saw that I can/should tighten down the carrier bearing preload. Looked at the pinion bearing diy and not sure it is within my DIY skill level. I would be happy to send it off to him, but see that he is not accepting mail-ins for the foreseeable future.
- Is the dealership the best place to bring this as an alternative? Not sure I trust any of the local transmission/4x4 shops around here to not butcher it, also not sure I trust the dealer... I am located in Northwest Indiana, so have access to Chicago area, Michigan, and Wisconsin.