Quick help: trying to pinpoint clunking near rear diff

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Last Flight Out

Last Flight Out

Joined
Feb 15, 2022
Threads
96
Messages
568
Location
Atlanta, GA
Can someone check me here… I have some low speed clunking/rubbing/binding sound that happens out of gear when I reverse the truck back or come to a slow stop. It is based on speed with this noise getting fast or slower.

Also get some clunking noise when My truck is in motion going backwards (not speed dependent as above), but I don’t hear it at normal speed - truck drives great. I’m trying to minimize areas of where this noise can come from. Rear DS is new, less than year old from Tom Woods. It’s definitely in rear drive line.

My understanding is I can remove the rear driveshaft and put the truck in 4high and that should at least let me know if it’s coming from the differential or somewhere else. Is this correct?

I know this is a common problem, but want to start with the easy stuff that I came take out of the formula to understand what it may be (inside diff, pinion nut etc).
 
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So while greasing the drive shaft u joints, grab the shaft nearby and push/pull and wiggle = do you feel play? Then check the pinion at the differential. Now jack up a wheel and rotate the tire back and forth, how much play do you have. Rock tire back and forth in/out , is the bearing loose?

You look/shake at other stuff - exhaust pipe, springs, shocks, mounts,

Yes you can remove the rear driveline and then drive in 4H or 4L for that matter.

You could also do a proper fluid change in the differentials plus the tranny and transfer. Look at the oil. Fish around in the drain with a magnet on a stick.
 
charliemeyer007 said:
So while greasing the drive shaft u joints, grab the shaft nearby and push/pull and wiggle = do you feel play? Then check the pinion at the differential. Now jack up a wheel and rotate the tire back and forth, how much play do you have. Rock tire back and forth in/out , is the bearing loose?

You look/shake at other stuff - exhaust pipe, springs, shocks, mounts,

Yes you can remove the rear driveline and then drive in 4H or 4L for that matter.

You could also do a proper fluid change in the differentials plus the tranny and transfer. Look at the oil. Fish around in the drain with a magnet on a stick.
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Like it @charliemeyer007 !
 
My e-brake shoes would do that when coming to a stop, wierd sound, thought my clutch was done, took 1 click off, noise went away.
I have never had my rear drums do that with shoes tight, the drum gets hot going around the block, I would seat the shoes, run around block, let em get warm, once or twice, back off 1 click if they are still getting too hot. If you can spin the tire and not hear or feel any drag at all from shoes they are not too tight.
 
Update…. taking a break for tonight cause I got things to do, but I undid the four driveshaft bolts to the rear diff, and when I was spinning it around, there’s definitely some clunking and grinding going on inside the pumpkin. It’s there, but what worries me even more is if it’s possibly coming from the transfer case and down the driveshaft (just had t-case rebuilt in early 2024). I won’t know until I get the rear differential and separated from the driveshaft and then spin the differential by hand. But it looks like that’s what the issue is…for now.
 
charliemeyer007 said:
There you go. Take notes on what you find. I bought a phone inspection camera wand off Amoron for like $40, It can look around inside cases - plus it does vids with sound.
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Yeah man, I’ve seen one of those and I believe 10mmGarageGuy on YouTube uses one in one of his videos and I thought it was the coolest thing. I also know they make small microphone pick ups that you can place around and a vehicle to hear where noises might be emanating from, but that seems a little too much in my mind.
 
Just got one! This weekend I will have all the answers… I just need to know what I’m looking for. So I’ll go ahead and drain the diff (replaced all drain plug ls last year with the improved hex units) and I’ll finish the endoscope in through the fill cavity to see if I can see any chunks of metal missing off any of the teeth assuming that this is where the noise is coming from.
 
I always start out by looking at what I changed last.
Checked your oil and grease everywhere?
Do you have handbrake on the rear drums or T-case?
Check they fitted the correct adjusters and mechanism in the rear brakes, and that they haven't moved - mine is a transition year and has handbrake on the transfer case, but also uses the later handbrake type rear brakes adjusters - most parts available but i ended up making a part to fully restrain it in the end.
 
Here is a similar response I would give you from this Post here on trouble shooting the rear end noise. . I've experienced the clunking noise too. One of the causes was a loose drive shaft due to the bolts being loose. Other was actual diff was worn out or something.... Replaced the rear diff 3rd member and it went away.
 
Update #2 - gutted. It’s something in the transfer case now. Not rear diff or rear hubs. Turning DS attached to the TC, turns and binds, unable to turn completely by hand (everything in neutral).
 
Last Flight Out said:
Update #2 - gutted. It’s something in the transfer case now. Not rear diff or rear hubs. Turning DS attached to the TC, turns and binds, unable to turn completely by hand (everything in neutral).
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Brother, the clunking noise in my 40's t-case turned out to be the high gear missing a few teeths -- :oops:

HWBZ3413[1].webp


Hopefully yours is something simpler.
 
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Last Flight Out said:
Update #2 - gutted. It’s something in the transfer case now. Not rear diff or rear hubs. Turning DS attached to the TC, turns and binds, unable to turn completely by hand (everything in neutral).
Click to expand...
Could still be a U-joint?
 
I'm thinking no/low gear oil in the transfer case - either leaked out the e-brake seal or pumped up into the tranny.
Maybe its just engagement issues - try shifting 2H to 4H then to N and then L and back - does it turn better in any position? Look at the gate and the bushing on the mechanism.
Have you found metal on the transfer case drain plug - shavings, powder, gear teeth. Magnet on a stiff wire to go fishing.
 
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