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Rear end info needed.

1948 Views 23 Replies 10 Participants Last post by  Steve V
I've always had a wine in the rear end when cruising under really light throttle. I thought I had a tire vibration and I went to get them rebalanced,they were fine. I got the guy to test drive the car(he's small shop nice guy) and he says I've got a bearing in the rear end gone. We put it on stands and let the wheels spin and yup there's a noise. So I guess I am gonna learn how to fix a rear end next. New bearings for sure,what do you guys think about the posi and the gears. How will I be able to tell if they are bad and need to be replaced??My car has 240,000 miles on it so I know I have a lot of these type projects ahead of me :D I am rebuilding it a little at a time.
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if it was mine id change all the bearings and seals, check the axles for wear near outer bearing, and you can tell if the rear gear is good by how it is wearing. both sides of the gear should be smooth and shinny like chrome if there is any lines or steps where the gears have ben running the gear will never be silent again and will need replaced. the posi should get new clutches if you plan on running the car at the strip. they are fairly cheap and it will help your car hook up. at 240.000 miles they are surly worn.
I'd tear it down and inspect it.You could be hearing gear wear or carrier bearing wear.
Could even be pinion bearing wear.
I just went through that a year ago at about the same mileage,but I knew what was coming.
Thanks,for the info. Where can I get clutches for my posi?Anyone have an exploded diagram of one,not familier with them at all.
The pinion bearing usually goes first and easy to change. But at your mileage it's like giving a 95year old lady a face lift. Contact gears R US or Randy's Ring & pinion. I think they are both listed in the vendor section. They both have detailed instructions in there kits and I think on there websites. This job will go much easier on a lift with power tools. There are many special tools needed and be ready for a broken carrier pin. This is a pain in the a$$ to drill out on floor jacks. You need a machine shop to press bearings on the carrier unless you have a press.
Just some more info, if your noise is happening under a slight load like you have described then it is ring and pinion noise(gear noise).If the noise happens when you take your foot of the gas pedal then it is pinion bearing noise.Or if your noise is always there then carrier or axle bearing noise.With the milage that is on the car recom all bearings.Make sure who ever is doing it that they know what they are doing and have done it before.Or prepare for more noises.Hope this helps.
Thanks for the help,everyone. I have access to all those tools,I work in a transmisson shop.Tommorrow nite I am going to put it on the lift and secure it then run it and listen to the bearings. i will probably replace em all,with the ring and pinion and try to salvage the posi unit. :)
Bet on bearings,seals and gears.
Here are the two suppliers I mentioned. They both have good prices and stock. Gears R Us Had all my parts to my door in two days.

<small>[ October 23, 2003, 11:24 AM: Message edited by: ULYCYC ]</small>
My original stock 87 GN came new with a whine at about 50 mph. Buick tried to eliminate this inherent noise by shimming the trans mount (changing the pinion angle. The dealer finally rebuilt it under warranty and the noise was still there! A junk rear end in my book (corporate shared one) My 13K mile rear has terrible gear noise in it now, might go to another one. To build my stock one with a good Auburn posi, Moser axels, 9" outer flanges etc. cost about $2K. A Moser 12" cost a little more and is much better unit in my book.(welded in tubes, thicker walls, non C-Clip axels and an Auburn Posi with 400 # springs) You might try some additive to lower the whine. Gene
Now that I think of it not sure if there is a spacer under my trans mount :) I am definatly gonna open it up next week and atleast put bearings and seals. Not gonna spent 2k on it though,it will have to wait for that :D
I went to both of those sites thumb_up Is there a site that has really detailed info on how to set the backlash,pinion depth and crush?
my rear is quiet. no noises. the only thing i gotta say about it is that the posi locks under full lock turns
You can get general info in the service manual. But some gear makers prefer there own pattern on there gears like Motion Gear. I'm not sure how quiet you will get 240,000 mile gears after resetting. I think since it will be all out do the complete job.
I wouldn't even think about reusing 240,000 mile gears.
Put in new gears and freshen up the posipacks.
One good launch at the track and......
That is my plan,new gears,bearings,seals. Hope do it next Sat if I can line up the lift,that's why I am gathering all the info on how to correctly set up my new gears. :)
My friend had a slip diff. in his car and got a possi put in it by a good mechanic and it whines on acceleration. Everything works fine...its just annoying as hell! moon
"it whines on acceleration." Mm, there's nothing in a posi that should make it whine. Especially since the posi isn't doing anything unless you're going around a corner. Under acceleration in a straight line, the posi is tight, nothing is moving, so there's nothing to make a noise. The whine might be the gears, or a bearing, but it wouldn't seem to be related to the posi.
I agree with Ormand.Something is wrong with the gear setup or they're just worn.
its funny that this topic came up cause i am now getting a slight whine only when i accelerate. and its not a constant whine, its like a wuh-wuh-wuh-wuh wuh- i know its hard to explain and sounds stupid but like i said it does it only on acceleration not when i let off. any ideas?
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