Topic: Rear differential problems + other noises

[ToniCipriani]

A short while back my diff started leaking, but it seems like it got to a point my mechanic recommended me replacing the entire diff as it was whining and making clunking noises. Bought a new diff from a local dealer and got them to installed it, now I have a vibration that I couldn't get rid of once car hits 80 km/h.

Took it back to them, they re-tightened everything, seems to have dampened a tad bit, but it's definitely still there.

Anything else I should try? Did I get a bad diff, or something else is going on? They told me it's not likely that the diff is bad.

Also have these noises unrelated to the diff:

- From the back of the car, usually happens when car is cold and I come to an intersection and start again, but it is completely random, usually at low RPMs. The noise sounds similar to a water drain when the last bit of water gets sucked in, that noise but continuous.
- Rear sometimes would make a "pop" noise after shutting down. It seems to be coming from the muffler area

Any ideas what those might be? Thanks!

[Gentleman Jack]

There was a TSB for the leaking diff

Any video of the new noises?

[ToniCipriani]

Yeah, the plastic valve leak one. That's what I thought initially and wanted to do that mod, but it seems like on my old one the leak was beyond that plus the grinding noises so I opted for a new diff. The diff runs fine now, no noises or anything except for that rumble after 80 km/h. One explanation I was given was that the tolerances on the old diff and new diff is different, I went from the original plastic valve 2006 one to the final 25968531.

As for the other noises, I tried making a video, but the noise was loud and it crackled the microphone, had the webcam on the rear bumper, plus my laptop was refusing to co-operate to capture the video, so that failed. I'm gonna try it again soon.

[Sol Asylum]

How about some details on your car like year and model, maybe mods you have done?

[ToniCipriani]

2006 2.4L Base, Manual, bone dry stock. Only mod done is the GMPP intake. I do have a limited slip diff option, under 34k kms on the clock now.

[Sol Asylum]

So the early cars like yours and mine had a factory recall on the dif, don't know how that would work in Canada.  The front input shaft seal would leak and once enough fluid had leaked out the gears would destroy themselves in short order.  The repair was to replace the input flange and seal assuming enough fluid hadn't already leaked out, if that was the case they replaced the dif.  Kind of too late now to know if that was your original problem.

Your vibration could just be because they have something that is out of balance or was put back together out of phase.  Also to change the dif they would have some suspension components loose or removed, they may not have gotten all of that torqued properly, amazing how many techs don't use torque wrenches these days.

Can't say what your drain sound is, water in the muffler?

The popping sound could just be normal expansion contraction as the exhaust cools down.

[ToniCipriani]

I'll bear that in mind. I still need to go back to do the initial diff fluid change after break in, so maybe I'll force them to retorque everything in front of me using the wrench.

Other than annoyance it's not a safety concern I suppose?

[ChopTop]

I know you said diff was new but sure it wasn't remanufactured?  Also, request they take if for a test drive (w/you riding shotgun) to verify issue. 

[ToniCipriani]

Sure the diff was new and not re manufactured?  Also, request they take if for a test drive (w/you riding shotgun) to verify issue.

I bought it from a GM dealer. I called them up, they said it's fine but for them to look at it, it's gonna cost me, if it's found out the diff is not at fault.

[ChopTop]

BTW, was installation GM mechanic or an independent?

[ToniCipriani]

BTW, was installation GM mechanic or an independent?

Independent. I brought it to my mechanic, serviced 2 cars with him already.

[DaveOC]

Cross-reference to the BB:

http://www.solsticeforum.com/forum/f12/aaaah-more-weird-noises-75193/

This pretty much all deals with the rear differential.

[ChopTop]

OK, reason I asked is I recently had a coolant flush and fill performed.  Drove 50 miles to a Cadillac/Buick dealer (formerly Pontiac too).  They removed the old coolant by suction, and refilled.  Before I left dealership driveway coolant light came on, since I was very low on gas I drove about a mile to gas station, opened hood and noticed overflow tank was about a quart low.  Drove right back, it was refilled and the tech took it for a test drive to make sure it was OK.  Was told because they use pressure to refill cavitation (coolant & air mixed) may have occurred.  No lights and stayed around 190 on drive home.

[ToniCipriani]

OK, reason I asked is I recently had a coolant flush and fill performed.  Drove 50 miles to a Cadillac/Buick dealer (formerly Pontiac too).  They removed the old coolant by suction, and refilled.  Before I left dealership driveway coolant light came on, since I was very low on gas I drove about a mile to gas station, opened hood and noticed overflow tank was about a quart low.  Drove right back, it was refilled and the tech took it for a test drive to make sure it was OK.  Was told because they use pressure to refill cavitation (coolant & air mixed) may have occurred.  No lights and stayed around 190 on drive home.

Oh yes that. I had my coolant pump replaced at a dealer too, and I had to double check to make sure they used the hold tool properly to replace the pump.

[TecSolOnt]

  I had a similar noise to yours,  grinding with the limited slip differential.  Too bad you replaced it because there was an easy fix at least it worked for mine.  There is a GM TSB out there somewhere.  What the dealer did was drain my diff ,  put new fluid in ,  go out and do circle 8's in the parking lot for 10 minutes or so,  then go back in and drain the diff again, put new fluid in again and then put a recommended GM additive in.   Diff was perfect after that.  The whole circle 8 thing is even in the GM TSB,  guess the clutches must get gummed up or something and this routine cleans them out.   I had about 25k miles on it when it started acting up,  been great since.  Wouldn't surprise me in time I have to get it done again.

Here is something from the Cadillac forum which shares the same diff...

Subject: Shudder Or Bind On Low Speed Turns - keywords axle differential
groan growl moan noise rear slow vibration #PIP3152J - (02/09/2007)

Models: 2004-2007 Cadillac SRX, CTS, CTS-V
2005-2007 Cadillac STS
2006-2007 Pontiac Solstice
2007 Saturn Sky
Equipped with Limited Slip Differential (RPO - G80)

This PI is being superseded to update recommendations. Please discard PIP3152H.

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

Condition/Concern:
Customer may comment of a shudder or bind from the rear of vehicle on low speed turns such as parking lot maneuvers on vehicles equipped with G80 limited slip rear axle. This condition may be more noticeable with the vehicle at operating temperatures.

[Critterman]

I have never heard of that before.  When mine started chattering they replaced the diff.

[ToniCipriani]

  I had a similar noise to yours,  grinding with the limited slip differential.  Too bad you replaced it because there was an easy fix at least it worked for mine.  There is a GM TSB out there somewhere.  What the dealer did was drain my diff ,  put new fluid in ,  go out and do circle 8's in the parking lot for 10 minutes or so,  then go back in and drain the diff again, put new fluid in again and then put a recommended GM additive in.   Diff was perfect after that.  The whole circle 8 thing is even in the GM TSB,  guess the clutches must get gummed up or something and this routine cleans them out.   I had about 25k miles on it when it started acting up,  been great since.  Wouldn't surprise me in time I have to get it done again.

Here is something from the Cadillac forum which shares the same diff...

Actually I think mine is more damaged than that. My mechanic pointed out to me that when clutching in, it started knocking really badly (and no, it's not the 2006 clunk, it was much louder). When I went back for the vibration, they showed me my old diff, disassembled. the diff was worn out on the outer ring, which is why it made that noise.

Anyways, here's my plan to try to fix this. I'll wait and carry on using my car till it hits 800kms / 500 miles to do the first diff fluid change, at which I'll ask them to retorque everything in front of me while the car is up. If that fails to cure the problem, I'll bring it to a GM dealer I used to service with. I checked with the parts dealer I bought, the diff I have does carry a 1 year warranty, but it must be inspected by a GM dealer first to prove the diff is defective before I can proceed with a claim, so I'll follow through with that. I just hope if the diff is faulty and I need a second install, the warranty will cover that (EDIT: GM Canada said no. What kind of policy is that?).

If all fails... I might just trade in my car for an ATS. Really don't want to get to this because last thing I need is a new car payment. Although I do have to say I'm lusting for that Black Diamond Tricoat 2.0T with 6-speed manual.

[elff]

Check the bolts for the driveshaft specifically and make sure that is still balanced

[ToniCipriani]

Check the bolts for the driveshaft specifically and make sure that is still balanced

Actually I was wondering about this. How exactly do you balance the driveshaft? All my research at this point seems to point to it being out of balance. I've seen something about welding weights onto the shaft but doesn't seem like the manual mention anything about it.

[elff]

U r correct,they weld little plates into them. 

[ToniCipriani]

Also I suppose for the driveshaft balance, I need to find a place that specializes in driveshafts? It doesn't look like my shop has equipment for servicing driveshafts.

[ChopTop]

Was going to ask if you had a manual or auto because thinking is if the driveshaft is out of balance wouldn't it vibrate when rowing between gears, and if auto it seems theoretically it would too?   

But your OP says: The diff runs fine now, no noises or anything except for that rumble after 80 km/h (49MPH).

Does that mean once you hit 80 km/h the rumble starts and continues as the speed increases?

[ToniCipriani]

Didn't quite catch what you mean. You mean for the driveshaft out of balance, I should feel the vibration only when shifting?

I have a stick shift. Maybe I'll try shifting to neutral when the highway is empty at night.

[Sly Bob]

I have a stick shift. Maybe I'll try shifting to neutral when the highway is empty at night.

You're in Toronto, the highway's never empty...   

[ChopTop]

First you said you had diff problems, then out of balance driveshaft issues, trying to understand if it's one or the other or both?