noise coming from rear end, please help! - Truck Forums

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Old 12-06-2008, 12:40 AM
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Join Date: Dec 2008
Posts: 7
Default noise coming from rear end, please help!

***I have posted this in a different truck forum online and I haven't gotten many responses so I am trying here***[/align][/u][/align]What happened[/u]
I was driving around today about 35-40 mph and all of a sudden I kept hearing this grinding/clunking noise coming from the rear end. I was almost home so I drove it slower to 20-25 mph because it sounded like my driveshaft getting ready to explode (I've had that happen before on an 85 Toyota at the carrier bearing). Anyway, I pull in to the driveway, chocked the front wheels, put it in neutral and jacked up the rear end, had a buddy spin the rear wheels while I was underneath, and the noise was coming from the rear of the driveshaft at the differential.

What I've done so far to this point[/u]
I checked the fluid level in the differential and it was BONE DRY. I took another vehicle to get some 90W gear oil, filled it level with the drain plug and buttoned it back up. Dropped it back down, went around the block about 30-35 mph and it was fine. Took it to the highway and drove 60-70 mph and it was fine. My thoughts at this point are "No more nasty sound coming from my truck! Easy fix, yay!".

The turning point/climax/evil[/u]
I got back on the same original road heading towards my house that all the noise started on, same original speed before the gear oil refill, just before the road I turn on to my soon as I cut the corner, I heard it again!!! I went around the block a couple more times turning each time to make sure I heard what I heard, and even when going straight, and it DEFINITELY still makes the grinding noise.

What I can tell/my thoughts[/u]
The U-joints look fine although I will replace them anyways once I have everything apart anyway (what can it hurt?). HOWEVER, there is A LOT of play in the PINION BEARING (I can take the rear end of the driveshaft and shake it around!) and there is a slight amount of gear oil leaking out onto the yoke so I think that I am going to have to replace the pinion bearing and pinion seal. If that is the case, I know that won't be an easy 30 minute fix, but more like 5 to 6 hours, maybe even a couple of days with the weather being like it is.

How do I fix it?[/u]
I'm pretty sure for me to change out this bearing and seal, I am going to have to pull the wheels off, rear drums off, pull the axles out, take the differential cover off, drain it out, gut the whole thing just to get to the pinion bearing. I would inspect each and every thing during the removal process and note any problems on anything and post it on here. What part numbers and exact specifications should I be looking for? I would be looking for an inner pinion bearing, would it be for an 8.5" R.G., would there be any specific lengths/diameters/radiusus on the bearing? Also what special tools would I need (other than the ordinary wrenches/ratchets/sockets/screwdrivers/hammers)? Is there a special way to put the bearing in if that is the case? Has anyone ever done this before and could provide a detailed explanation on how to do it?

What I would get if nobody had specifics:

-K1500 Pickup
-5.7L 350cid V8
-Differential Pinion Bearing

***then these would be the ones I would toggle with because I don't know which exact one to get*** I'm assuming it is the inner pinion bearing and not the outer

I believe this part fits either application

Timken Part # M802011
Cup; Front Axle, Inner 4WD; 8.25" R.G.
Cup; Rear Axle, Inner; 8.5' R.G.; 1st Design $4.84

BCA/NATIONAL Part # M802011 {Taper Bearing Cup Outer Diameter=3.25" Length=0.795" Radius=0.125"}
Taper Bearing Cup; Front Axle; Inner; AAM IFS-8.25" R.G.
Taper Bearing Cup; Rear Axle; Inner; AAM 8.5" R.G.

Cup/Cone/Taper....I have no idea

TIMKEN Part # M802048
Cone; Rear Axle,Inner; 8.5" R.G.;1st Design
Cone; Front Axle,Inner,4WD; 8.25" R.G.$9.88$0.00$9.88
BCA/NATIONAL Part # M802048 {Taper Bearing Cone Bore=1.625" Length=1.01" Radius=0.14"}
Taper Bearing Cone; Front Axle; Inner; AAM IFS-8.25" R.G.
Taper Bearing Cone; Rear Axle; Inner; AAM 8.5" R.G.

-Differential Pinion Seal

Timken Part # 2043[/b]
Rear Axle; 8.5" R.G.; 1st Design $4.17[/b]

I don't consider myself to be a mechanic by any means, but I have pretty good common sense, so I guess that counts for something. I would prefer to learn how to do this myself vice taking it to a shop.[/align][/align]I have never rebuilt or set up a differential before. Even if I did take everything apart and replace all the worn parts, what would be the point in taking it to somebody else at that point? I might as well let them do it start to finish. What special tools would I need to set the clearances and such, and what would they be for each part that needed clearance and such?

If I take it apart and put it back together the same way I took it apart, I would think that there would be more things involved than just do that. And if it is as easy as some people havemade it sound (***from the other forum***), I'm sure something would mess up.

I'm sure it is not hard to do given I had detailed instructions and the right tools. I found a kit from rockauto, below is the picture and details of what it is.I know how to drop the drive shaft, I have an idea how to get the drums off but it is in the book, the axles I know are in the book, the gears that's a trial and error and I think some of it is in the book, and the rest should be easy. My thing is the clearances and such and the special tools I will need to do this. An impact gun to me would not be special, but I do have one.

BCA/NATIONAL Part # RA321{Bearing/Oil Seal [/align]
Rear Axle; AAM 8.5" R.G.

I do want to and need to get my hands dirty but I need direction first to get to that point![/align][/align][/align]***Update that I have not added to the other website forum***[/align][/align]I pulled the differential cover off, drained all the oil out of it, and the first thing that I seen was a BOLT resting at the bottom of the differential. It was one of the ring gear bolts and it was all chopped up and chunks taken off of it. That was the really loud noise I kept hearing in the rear end when I was driving around with no gear oil. And after adding the gear oil, it had quietened down only because it would take it a while to move through the oil while ricocheting off of the ring gear and what not. Plus, the rest of the ring gear bolts were 1/4 of the way up to 5/8 of the way BACKED out of the threads of the ring gear. Somebody had this apart before and didn't torque them down to specs (reason why I have the other post about the torque specs and process) and/or add threadlocker (medium strength). Or it hasn't been messed with and it's just 12 years of vibrations and driving that made them back out. Well now, I've reached the point to where I've driven it down the road (not even a quarter mile) to the local auto shop and they said $1200 to redo the whole rearend. I need to be able to do this for under $200 and do it myself and be done within one week from tomorrow (Saturday). The yoke still has play in it and I have replaced the chopped up ring gear bolt from a dealer. Would I need the bearing and seal rebuild kit, or do I really need new axles, posi, etc.? Is it really that necessary? All I should have to replace I think is the pinion bearing, the crush sleeve (that one seems complicated after talking to a 4x4 shop today), and the pinion seal. I really, really need help with this and I appreciate everyone that has taken the time to read this crazy post, and just might be willing and able to help me out. I really can't afford taking it to a shop.[/align]

Anybody have any thoughts/advice/ideas?

I appreciate any and all replies. Thanks for reading[/align]
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Old 12-06-2008, 06:09 AM
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Join Date: Feb 2007
Posts: 2,167
Default RE: noise coming from rear end, please help!

Well,to fix it right,you need a ring/gear pinion,plus all the bearings and maybe even a carrier since it was run dry....those parts new will be in the 1500 dollar range....The rear end will howl at highway speeds with an overheated ring gear.Plus,as much damage as you have,its highly likely the case is also damaged.

This is very tricky to install and set takes precise measuring with a dial indicator and marking grease to do the job correctly.I think you should probably just put a used rear axle in.A lockerr will run you about a grand usually.
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Old 12-06-2008, 01:59 PM
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Join Date: Oct 2008
Location: Monroeville Pa
Posts: 196
Default RE: noise coming from rear end, please help!

Argon is right. You'r rear is shot, and will need a complete rebuild. Rebuilding a rear is not something you want to mess with by yourself if you don't know what you are doing. If you don't have the right equipment, or don't get everything put in properly with the correct clearences, backlash, etc. you will end up eating that $1500 in parts in no time. I've had the rear rebuilt in my truck twice. The first time Chevy covered it, but the second time it cost me $1500 (parts + labor).
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Old 12-12-2008, 02:42 AM
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Join Date: Dec 2008
Posts: 7
Default RE: noise coming from rear end, please help!

I cleaned out the differential after I torqued down the ring gear bolts to 90 ft. lb., put the cover back on, and I am currently in the process of adding the gear oil/posi additive.

So of course the clunking noise is gone since I put a ring gear bolt in and tightened them all down. However, there is still the play in the yoke and pinion bearing/shaft. I believe the pinion bearing to be bad and that's it, however seeing as to do this myself, I'm going to have everything apart anyways so I might as well get new bearings for the carrier, pinion, and axles. It's a kit and it is $70 from rockauto. I talked to a guy on the phone at a nearby 4x4 shop and he said that if I replaced just the bearings and seals, and the crush sleeve, and some kind of shims (I don't know what he was talking about there) that should be all the parts I need to fix it. The tools I don't have but maybe could borrow from somewhere. And at this point I'd have parts and tools and all I would need is directions. I know it's not as simple as putting it back together the same way I took it apart. Has anybody ever done this before and could walk me through it step by step? Somebody said in an earlier post the steps are in the Chiltons books. I went out and bought one and it is not in there. Maybe an older Chiltons, one of the thicker books before some genius decided to not include everything on a complete tear down and rebuild. It doesn't sound complete to me. Please, I am begging anyone and everyone. Please, I need help with this.[/align]
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Old 12-12-2008, 10:47 AM
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Default RE: noise coming from rear end, please help!

Buy a new truck or a late model used one!!! Prices are great because of gas and economy.
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Old 12-12-2008, 10:25 PM
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Default RE: noise coming from rear end, please help!

You know somebody that would pay my monthly payments, cause I know I can't
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Old 12-15-2008, 11:45 AM
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Join Date: Jul 2007
Posts: 666
Default RE: noise coming from rear end, please help!

Alright man, I will help you. PM me and I will walk you through it. If that is not suiting your fancy, than I would say to try and find a tutorial on the web about how to rebuild rear differentials.

I have done a few diff rebuilds, two on 70's blazers and p/u's, also the one on my current truck. Well that was just a teardown, but that was because I was in a parking lot with only the tools in my small tool box. It sucked. I ended up getting all of the rear end dissasembaled, but then I ran into a problem getting the one side of the axle out. It was wedged in place because of the carrier bearing being completely gone. That sucked! I paid 1200 for the new carrier assembly. That's when I went to a posi rear diff, instead of the GM locking rear. I am so much happier!
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Old 12-16-2008, 04:52 PM
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Join Date: Oct 2008
Location: Monroeville Pa
Posts: 196
Default RE: noise coming from rear end, please help!


some kind of shims (I don't know what he was talking about there)[/align]

Are you serious!?! You are going to get yourself in way over your head if you try and do this yourself. I'm just sayin.
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Old 12-18-2008, 05:17 PM
Join Date: Jan 2008
Posts: 61
Default RE: noise coming from rear end, please help!


Listen to what these folks are telling you, if its for a 96 chevy pickup.

Just go to the junk yard and pickup one.

Its way too much trouble to rebuild it your self, if you do not have the proper tools.

Just my two cents!!!
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Old 12-25-2008, 11:38 PM
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Join Date: Dec 2008
Posts: 7
Default RE: noise coming from rear end, please help!

well I would think given direction, and knowing what proper tools/parts I need, it couldn't be rocket science. Besides, pulling another rear end out of a junk yard would cost more money than the parts and renting the tools and doing it myself. And then eventually I'd have to worry about that pinion bearing going out sooner than I would if I was to put new bearings and seals in the entire thing! I did ask a local 4x4 shop about how much he would charge to change them out, and he said $350-$500. If I had the direction, I could do it for $0. I don't work and am on unemployment, and I cannot afford to just go get a used rearend out of a junkyard, or take it to a shop and have somebody else do it. I don't know anybody that knows somebody that can hook me up, so I'm trying to use as many resources as I can to limit the cost of the repair. Thanks again to all who have responded
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