I think my rear end is making noises...

[d0n_3d]

As I drive down the road, I constantly hear a wuh-wuh-wuh-wuh-wuh-wuh sound and it's coming from the rear of the car. I haven't had a problem until this past month. The gear oil hasn't been changed in exactly 1 year. I am not sure if I am just low on fluid or it needs changed or something is wrong? The sound gets faster as the car goes faster...goes slower as the car slows...it's not suspension related and everything clears everything ok.

When I was putting my tires back on yesterday after doing a lca install...I torqued down the lugnuts with the car jacked up and you know how the rear end isn't supposed to turn the tires when in park? Well it took alot of force but I got both tires on the rear axle to turn. I thought it wasn't supposed to budge when in park? Does that mean there's something wrong with the rear???

 

[SuperSix]

Doesn't sound good - unless the pawl in the tranny was clicking (that would take a LOT of force) sounds like your clutches are toast. Was the driveshaft turning with the wheels?

 

[d0n_3d]

forgot to mention that i did a small burnout and then shot off squeeling the tires at a local stop sign here and i went back to check my marks and i only left the right side tire mark...I HAVE POSI...this doesn't look too good now that i think about it

 

[SuperSix]

Originally posted by d0n_3d
forgot to mention that i did a small burnout and then shot off squeeling the tires at a local stop sign here and i went back to check my marks and i only left the right side tire mark...I HAVE POSI...this doesn't look too good now that i think about it

Sounds like you may get to learn how to rebuild a posi!

Of course, you should check the fluid, NOW, it may be very low, top it off, add some posi lube, and cross your fingers.

 

[GNFURY]

i WOULD ALSO CHECK THE TIRES IN THE BACK FOR BROKEN BELTS AND MAYBE LOOK AT THE WHEEL BEARINGS ALSO. (BEFORE Y0U DIG INTO THE TRANNY.....)

 

[soonergn]

Sure sounds like an axle bearing to me.

 

[soonergn]

or you have gas Do you feel ok?

 

[1970gsx]

Or... you can ignore the noise for alot longer and end up towing it home for $120 and replacing everything inside the carrier like I did.

 

[Tom87GN]

Bad timing

Don, this is really wierd and bad timing. I just picked up my GN from my local mechanic and I've got two slightly bent axles. My car has been humming and vibrating like mad between 55-65 for about a year now. The posi still works fine, but I need new axles. Maybe there is a black cloud hanging over our state right now.

 

[soonergn]

'70gsx is right, a bad bearing can spread metal debris through out the diff and damage EVERYTHING so don't let it go if that's what it is.

Also one rear wheel at a time can move when in park, you're just overcoming the clutches in the diff. Betcha can't move 'em both in the same direction at the same time!

 

[turbocamino]

Sounds like a bearing going bad. Here's how to tell which one: Get up to speed so that the noise is loud.(about 45-50mph). start to accelerate. Does the noise get louder or go away during during acceleration? Then put the car in second gear, let off the gas and let the engine speed slow the car down. Either way, if the noise changes, it's the pinion gear bearings. If no change in noise, then get up to speed again and swerve from side to side with the car. This will load one or the other side carrier bearings. If the noise changes from side to side, it's a carrier bearing. If still no change is noticed, it's probably a bad axle bearing. In this case, you will need a new axle along with the bearing (the axles on these cars act as the inner part of the bearing and the axle surface actually wears out). No matter what bearing is bad, don't ignore it because it will cost you big time if you wait till that bearing breaks. Like what was earlier said, when you tightened your wheel and it spun with the trans in park, you were overpowering the grip of the posi clutches. The worse the condition of the clutches, the easier it is to have this happen. Also, if you make a right turn while spinning the wheels, sometimes you will only get one wheel to spin because their is not suffient grip from the right side wheel to lock the clutches if they are worn. If your turn left when you step on it, both wheels should spin. That just means your clutches are worn. Anyway, good luck with it, Jeff

 

[d0n_3d]

ok guys...say it is the axle bearings which i think they are...how do you replace them? i have the tires and brake covers off...how do you change the bearings or do i have to remove the axle or what? the noise does get louder the faster i go...when i let off the gas and let the car decelerate the noise is still there...

i called autozone and they said bearings are 8 bucks a piece...so what's the scoop? what should i do here...i don't want to ruin my rear end if it's still good...hell if i know the way this is going

 

[Jon01]

Edit-does the noise change when you're turning on an on/off ramp or something that you're moving pretty good on a tighter turn? If so, it may be wheel bearings.
Anyways, here's what I remember from pulling an axle out of a gutless.
I'll assume an 8.5 is the same as a 7.5, so here goes...
Get car in the air, supported, etc.
Pull cover off diff.
Rotate carrier around until you see a small bolt-3/8 head I believe. Remove this bolt.
There's a large arge pin should be free to remove. Pull it out.
IIRC, the spiders are now free, remove them(might want to note locations so you put them back in the same spots)
Pull the c-clip off the end of the axle
Now the axle should be free to remove from the tube. Be careful of the seal on the end of the tube.
Hope this helps
Jon

 

[d0n_3d]

well...i don't know what to do here...we have ruled out that it's either rear end related...axle related...or transmission carrier bearing related...not sure where to start...i think the rear end is fine...the noise does get louder when i turn corners...that must indicate it's axle bearing related...the thing is do i need special tools to do this? and is there a detailed procedure somewhere on how to do this? i can't find any repair manuals about an 87 GN anywhere...so i just buy the axle bearings from autozone (set of 2 i think) and then take the rear end cover off and take off the axles that way and put in new axle bearings? if that doesn't work then i guess it's the carrier bearing in the tranny...

one thing to note...i tested out my posi today by swapping out back wheels with my stock wheels and smaller tires to see if i had rubbing tires...i had the same sound with the smaller tires and no rubbing...i did 3 smokey burnouts and left nice dark black tire marks all 3 times about 20 feet...so my posi does work obviously...i don't think the rear end is bad...maybe the axles are messed...

 

[Jon01]

Again, going from memory, but I think the bearings came out on the axles-pressed on.
Seriously sounds like it's either those or mebbe the pinion bearing, try grabbing the yoke and seeing if there's any play in it-up/down, side to side. Should be next to none, if any.
If I was you, I'd change the fluid asap to try and prolong the life of your posi, if it pulled a 1 wheel peel once, it's getting weak and anything you can do now before it's totally shot may help it last another year or two. Make sure you use good oil-I used the Lucas stuff in my old Mustang and it brought it back to life for another couple of years.
Good luck!

 

[turbocamino]

The carrier is in the rear end. It is the part that the ring gear bolts to, and it contains the spider gears and the posi clutches. On either side of the carrier, there is a bearing. My guess is that one of these is bad. An axle bearing won"t load and unload enough to change tone when you are going around corners. Anyway, you need a repair manual to understand what you are working on. Get a repair manual for any GM rear wheel drive car that contains a section on the rear end. They are generic enough for you to get the idea of how to fix it. Also, if you have a manual for a ford 7.5 or 8.8 inch rear(mustang), it is very similiar.
Note: if a carrier bearing is going bad and it gets to the point that it stops doing its job, it can start to rotate its own outer race and destroy the rear end housing and break the ring and pinion gears! I would re bearing the whole rear and avoid any seriuos damage. Every bearing can be bought for the rear for under $100 total. To replace a GN rear with set you back about $800 if you destroy it.

 

[Tom87GN]

Get the car up to speed and then put it in neutral. This will take the entire drivetrain out of the equation and tell you where the problem really is. I did this with my vibration and it was still there while the car was in neutral going 60 MPH. This tells me that it's either bad u-joints in the driveshaft or it's in the rear axle somewhere. After I had the driveshaft checked and everything was good there, I moved to the axle. Bent axles is my result. Moser's will be going in next week.

I'll be starting another thread to find out if I can round up any more info on replacing axle bearings.

 

[Big Mike]

I noticed the same thing was happening to my car one day.I Changed the fluid and still there.The next day my crown and pinion gears broke.I took eveything apart and the axels were straight.I ordered new 30 spline axels eaton possi,c clip elim. and richmond gears.I was going to change over the winter anyways.It only has 69,000klm.Go figure!

 

[d0n_3d]

i am going to pop off the rear cover right now and check the fluid...i will replace the gasket and fluid and if the noise still continues and i don't find any damage inside the rear then i don't know...i think i am just gonna have it worked on by someone else...i don't have the right tools, knowledge, nor time and will power to do all this work especially after spending 3 days on lca's and atr bar...

 

[d0n_3d]

k i took off the rear cover...drained the fluid...the fluid was very thick and did not have noticeable metal shavings in it...

what i did find interesting was there was a somewhat long skinny metal piece stuck to the magnet...like it was a part of a gear or something...lots of metal shaving debris grey stuff on the magnut...does that indicate the problem?