Almost at wits end and money trying to fix rear differential problems
11-03-2014, 03:42 PM
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Almost at wits end and money trying to fix rear differential problems 
Hang with me while I explain. I have a 2000 WS6 3.23 automatic TA with traction control. Bought the car 1 1/2 years ago with the intent to fix it up. It had 114,243 miles, no body damage, light chips & scratches. The only thing wrong with it was and obnoxiously loud rear and needing new tires. I was raised around a bunch of boys so I know enuff to be dangerous, but not skilled enuff to do the work. From the sound, I knew I was looking at wheel bearings at least... Original work I had done: rear pinion replaced, axle and wheel bearings. I was told all the spider gear in the carrier looked good. Had also gotten a set of spiders to rebuild the carrier if need be.... Couldn't use them cuz they were for posi (didn't know it at the time)and I don't have that. Got it out of the shop and it ran good for a couple days and I started hearing little familiar noises again, a weird grinding when in reverse (but not always), along with the bone shattering THUD, as if I had bottomed out, when going over lifts in the road/RR tracks, etc. Took it back to the shop and told them about it and left it for them to check out. after a day, was told they changed the fluid and it was fine. They didn't know what I was talking about. So, after a couple weeks and an increasing amount of noise I took my happy little female self back and took the guy for a ride and pointed out every issue I could hear and the grinding I could feel so they could no longer pass the "stupid female" card to me. I took it to another location of this business to have the work done because I no longer had trust with the original mechanic. Well, much to my not surprise, I was told the spider gears were no good and we'd have to rebuild the carrier, problem.... Try an find spiders for the 3.23 non-posi. Not going to happen, or at least not where I am. Basically had to invest in an entire rear assembly because no one would sell just the carrier. Found a real nice used assembly, original 45k for $345 and had it shipped. We salvaged all my newer stuff off the old axle and installed the new/used one. Mechanic there said its running great, no wiggle room, nice and tight with no noise when he drove it. I was estatic to go get it and feel the drive without the noise & grinding so I happily handed over my $1098 for the labor and parts (fixed the front passenger tie rod that was worn) and enjoyed the ride for all of a day. I now feel the weird rattle-loose bearing vibration when accelerating between gear shifting. Not as bad as it was at its worst and no noise, but definitely not what I was wanting . So now... I'm $3000+ into a rear end repair and it's still not right. Or am I just expecting to much? I have always wanted this vehicle, it is my dream. I don't know if what I'm feeling is "normal" for this vehicle or Is there something that they keep missing. I don't want to dress it out, I want it to remain stock. If any of you guys can help me out here with info I would greatly appreciate it. 
11-03-2014, 03:56 PM
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Oh... Just in case, pretty sure it's not the transmission. Shifting is nice and smooth. The wobble/rattle/grind is further back. Almost feels like a loose ball bearing
11-03-2014, 04:33 PM
#3
Welcome to LS1tech forum and maybe we'll be able to help diagnose before you start spending too much more money.
A better description of location of noise and you said "weird rattle-loose bearing vibration when accelerating between gear shifting". Automatic shifts happen fast,are you manually shifting ? "when accelerating"-normal,brisk,or wide open throttle accelerating ?
post this also here in the regional forums 'florida members',maybe some member local there can help diagnose it.
A better description of location of noise and you said "weird rattle-loose bearing vibration when accelerating between gear shifting". Automatic shifts happen fast,are you manually shifting ? "when accelerating"-normal,brisk,or wide open throttle accelerating ?
post this also here in the regional forums 'florida members',maybe some member local there can help diagnose it.
Last edited by FirstYrLS1Z; 11-03-2014 at 04:58 PM.
11-03-2014, 08:52 PM
#4
It has a posi/LSD, but it is a Torsen and doesn't "act" like an Auburn when jacked up. In fact it "acts" like an open diff, but apply torque and it will posi.
All V8 fourthgens had limited slip (G80) from the factory.
That out of the way, do you mean they replaced the pinion seal, or the pinion itself? Because the pinion should be paired with the ring gear.
Are you sure it is axle noise and not tire noise?
Does it still have the little aluminum cap over the top on the back? Its purpose is to quiet it down inside the car.
Could it be the U-joints?
All V8 fourthgens had limited slip (G80) from the factory.
That out of the way, do you mean they replaced the pinion seal, or the pinion itself? Because the pinion should be paired with the ring gear.
Are you sure it is axle noise and not tire noise?
Does it still have the little aluminum cap over the top on the back? Its purpose is to quiet it down inside the car.
Could it be the U-joints?
11-03-2014, 10:12 PM
#5
hey 981LE, what are you referring to when you said : "Does it still have the little aluminum cap over the top on the back? Its purpose is to quiet it down inside the car." ???
for 30yrdream: not sure how knowledgeable you are about rear axles and drive train. unless you take it to a shop that specializes in modifying that style car you are at a disadvantage, most shops will just slap parts in it and send the car out the door.
one thing not to overlook is your drive shaft and the universal joints on each end, the other is the strength and condition of the "torque arm". the torque arm is the big bar that connects from tail shaft of transmission to the front of rear axle housing and prevents the entire axle assembly from rotating in the opposite direction your rear wheels spin (newton's law action/reaction). if that arm is split at all where it mounts to the rear axle, or the bushing is shot where it mounts to the transmission then that will cause clunk problems. another big failure point is the "rubber transmission mount" that connects the transmission to the crossmember, they split/break over time and cause clunking when under power. so if you are at your wits end, or for anybody buying a used car in my opinion the tq arm should be removed if necessary and inspected, along with inspecting transmission mount.
for the rear axle, it's known as the GM 10-bolt, has a 7.625" ring gear. suggest you google [ring and pinion] and [differential] and [carrier] to understand what's what.
you can buy a new carrier for the GM 10-bolt having the 7.625", just google "GM axle carrier 7.625". the carrier is the main part that the ring gear bolts to, and what contains the "differential". there are many types of differentials- open which is most common and simple, then you have limited slip and gets fancier from there. the cheapest is the open differential and would be easiest to set up... or give you least worries. The differential has nothing to do with traction control.
when you have rear axle or rear end problems you have to diagnose it correctly, not just throw a couple new parts in there because if there are other bad parts then it'll just fail again. at minimum you need a new "ring and pinion gear set" which comes as a package, the pinion gear is matched to the ring gear. without knowing your problems in detail, i would suggest either purchasing a new carrier or having a competent shop inspect your current carrier for runout (it should rotate true and not wobble that is a common problem that gets overlooked). the other thing is get a new "pinion yoke" do not reuse your existing yoke, and that also must rotate with zero runout, a common problem. you should have both axles checked for runout, if they are bent or wobble then they will destroy the bearing they ride in, then get new axles. with the carrier/differential, i believe you can often get that as one unit then all that's needed is you bolt the ring gear to it, that would depend on how the shop or whoever does the work buys the parts from wherever. and last you would also want to verify that the axle tubes on the rear axle are also straight, if it's a used car and it bottomed out something could have bent a rear axle tube (and axle) which could be the underlying problem... all that needs to be checked out.
for 30yrdream: not sure how knowledgeable you are about rear axles and drive train. unless you take it to a shop that specializes in modifying that style car you are at a disadvantage, most shops will just slap parts in it and send the car out the door.
one thing not to overlook is your drive shaft and the universal joints on each end, the other is the strength and condition of the "torque arm". the torque arm is the big bar that connects from tail shaft of transmission to the front of rear axle housing and prevents the entire axle assembly from rotating in the opposite direction your rear wheels spin (newton's law action/reaction). if that arm is split at all where it mounts to the rear axle, or the bushing is shot where it mounts to the transmission then that will cause clunk problems. another big failure point is the "rubber transmission mount" that connects the transmission to the crossmember, they split/break over time and cause clunking when under power. so if you are at your wits end, or for anybody buying a used car in my opinion the tq arm should be removed if necessary and inspected, along with inspecting transmission mount.
for the rear axle, it's known as the GM 10-bolt, has a 7.625" ring gear. suggest you google [ring and pinion] and [differential] and [carrier] to understand what's what.
you can buy a new carrier for the GM 10-bolt having the 7.625", just google "GM axle carrier 7.625". the carrier is the main part that the ring gear bolts to, and what contains the "differential". there are many types of differentials- open which is most common and simple, then you have limited slip and gets fancier from there. the cheapest is the open differential and would be easiest to set up... or give you least worries. The differential has nothing to do with traction control.
when you have rear axle or rear end problems you have to diagnose it correctly, not just throw a couple new parts in there because if there are other bad parts then it'll just fail again. at minimum you need a new "ring and pinion gear set" which comes as a package, the pinion gear is matched to the ring gear. without knowing your problems in detail, i would suggest either purchasing a new carrier or having a competent shop inspect your current carrier for runout (it should rotate true and not wobble that is a common problem that gets overlooked). the other thing is get a new "pinion yoke" do not reuse your existing yoke, and that also must rotate with zero runout, a common problem. you should have both axles checked for runout, if they are bent or wobble then they will destroy the bearing they ride in, then get new axles. with the carrier/differential, i believe you can often get that as one unit then all that's needed is you bolt the ring gear to it, that would depend on how the shop or whoever does the work buys the parts from wherever. and last you would also want to verify that the axle tubes on the rear axle are also straight, if it's a used car and it bottomed out something could have bent a rear axle tube (and axle) which could be the underlying problem... all that needs to be checked out.
11-03-2014, 10:18 PM
#6
and being a used car and not knowing history and problems you've been having, i would also have the drive shaft sent out to be checked and balanced. you could have a bad ujount (universal joint), they are cheap like $20 each (there are two) so you would just have them replaced first by whoever then balances the drive shaft. with over 100k miles the smart/safe thing to do is have the ujoints replaced.
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11-05-2014, 07:03 PM
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Sorry for the late response... Work is crazy! Thank you all so much for your input and great information. Very true, I bought it used and there's no telling what all had been done with it so I started from scratch.. Tune up, new belts, new oil pan gasket (leaking), PCV valve that was cracked. Car was in great shape minus cosmetic wear and the rear end is the major problem. When they replaced the pinion they replaced the seal and the aluminum cap. Had a talk with the manager of the shop and we were discussing the U-joints. (Thought of it after remembering when my friends Challenger broke and dropped the drive shaft.) the rear I bought granted was used, but looked to be in really good shape. We transferred all new gear from my old axle if it was possible. I wrote down all the info you guys have shared and I'm going to speak with the guy tomorrow and tell him about it. I'll keep Ya posted on what they say and find. He's supposed to take it for a drive when he gets in in the morning so he can feel what I'm talking about. In the meantime... Working extra hours so I can replenish the paint job fund 😀
11-06-2014, 04:33 PM
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Ok guys, talked to the shop today and they are having the mechanic check the U joints, torque arm and rubber Trans mount. I'll get back on in a couple days and let you know the progress. You guys are awesome and I appreciate it SO much!