Author Topic: Rear differential problems + other noises (Read 19549 times)

ToniCipriani · « **Reply #25 on:** June 14, 2013, 12:50:36 PM »

Quote from: ChopTop on June 14, 2013, 12:36:46 PM

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?

It all started out with the diff leaking and clunking. After the diff replacement, original symptoms gone, but car started vibratin at 80+ km/h, and that symptom suggested it could be driveshaft?

ChopTop · « **Reply #26 on:** June 15, 2013, 11:38:20 PM »

OK, that's what I meant about RPM +gear +driveshaft. Seems like if the driveshaft was out of balance that it would vibrate in every gear when it reaches a specific speed? Regardless, I would imagine having it checked for balance will reveal if that's the issue.

ToniCipriani · « **Reply #27 on:** June 16, 2013, 12:01:03 AM »

Yeah, so just now I did a test to put car into neutral while cruising on an exit ramp from 100 km/h to stop, the vibration seems to be still there. So I guess it's safe it's not transmission or clutch related?

2kwk4u · « **Reply #28 on:** June 16, 2013, 01:55:38 AM »

As has been suggested by many, it sounds driveshaft-related. Possibly related to the coupler between the driveshaft and rear diff. Unless they replaced your driveshaft when they did the differential work, I doubt the driveshaft itself is out of balance (as it would have been out of balance before as well). It could be that the pinion within the differential is ever so slightly out of spec, though that seems unlikely as well. Regardless of what it is, I'd recommend getting it back to the shop that did the job and having them address it sooner rather than later. Whatever it is will only get worse.

Sly Bob · « **Reply #29 on:** June 16, 2013, 09:10:41 AM »

Might be worth putting the car up and checking to see if the bolts on the couplers on either end of the drive shaft are tight.

ToniCipriani · « **Reply #30 on:** June 16, 2013, 12:03:08 PM »

Quote from: 2kwk4u on June 16, 2013, 01:55:38 AM

As has been suggested by many, it sounds driveshaft-related. Possibly related to the coupler between the driveshaft and rear diff. Unless they replaced your driveshaft when they did the differential work, I doubt the driveshaft itself is out of balance (as it would have been out of balance before as well). It could be that the pinion within the differential is ever so slightly out of spec, though that seems unlikely as well. Regardless of what it is, I'd recommend getting it back to the shop that did the job and having them address it sooner rather than later. Whatever it is will only get worse.

I did once I first noticed the vibration. Took it back to them, they took it for a test drive 4 times and tightened the things down, it's still there, although much more dampened than it first was. At first I would notice I can't even get a clear image on my rearview mirror.

Now one thing interesting about the coupler. eSI says that the coupling nuts need loctite on them and to be torqued at 63 lb-ft. I wonder if that's the issue. Seems to make sense if they told me the vibration level was fluctuating.

ChopTop · « **Reply #31 on:** June 17, 2013, 03:39:48 PM »

Sounds like you need to find someone who specialized in troubleshooting driveline vibrations. Possible a pro race shop might be able to recommend someone?

Hopefully, you don't give up on the car because I think that's what generally happens to most people when they can't fix the issue and start blaming the car when in fact the blame should be directed to the people who worked on it.

My old mechanic has a saying; Cars are nothing more than a pile of metal and electrical and mechanical systems, so if it's not mechanical, or it's not electrical then it's probably the mechanic who worked on it.

Sol Asylum · « **Reply #32 on:** June 17, 2013, 08:34:31 PM »

Isn't there some angle between the trans an diff that needs to be set if you replace one of the components? Given how few "mechanics" read the manual these days I wouldn't be surprised to see that getting missed.

elff · « **Reply #33 on:** June 17, 2013, 09:59:29 PM »

Yup
Us lifted jeep guys abuse the crap out of that stuff.
But if everything was bolted back in, i dont see how the driveshaft angle could be off to the point of feeling it,
Also
You dont feel that as a shake, its more of a buzzing

ToniCipriani · « **Reply #34 on:** June 17, 2013, 10:02:32 PM »

Quote from: elff on June 17, 2013, 09:59:29 PM

Yup
Us lifted jeep guys abuse the crap our of that stuff.
But if everything was bolted back in, i dont see how the driveshaft angle could be off to the point of feeling it,
Also
You dont feel that as a shake, its more of a buzzing

Oh yeah it's a buzz alright. Feels like all of a sudden my car got a free massage chair installed... except all it does is make my bottom itch.

elff · « **Reply #35 on:** June 17, 2013, 10:06:53 PM »

Then that is a really good chance its the angle and/or not bolted up properly.
Im going to put money on it being driveshaft related at this part.

DaveOC · « **Reply #36 on:** June 17, 2013, 10:19:54 PM »

For what it's worth, notice that 3 of the bolts go one way and three go the other way, it's possible the mechanic has all 6 going the same way?

For what it's worth, back in the 2006-07 time frame I remember reading a couple of threads on another forum where there was a buzzing from the drive shaft. In both cases, the fix was replacing or retorqueing all the bolts on the driveshaft.

http://parts.nalleygmc.com/showAssembly.aspx?ukey_assembly=390451&ukey_make=1030&ukey_model=14651&modelYear=2006&searchString=drive+shaft

ToniCipriani · « **Reply #37 on:** June 17, 2013, 10:23:28 PM »

Well there's two more things I'm wary about:

- eSI states that for a diff install, the propeller shaft actually needs to come out first, then the diff, and then reverse. I'm wondering if they actually removed the prop shaft then reinstall, or just pulled the diff off and got it on in the wrong order, then somehow made it go out of balance with the new diff.
- eSI also states that Loctite is to be used on the bolts. They tell me after tightening it becomes better then becomes worse again, so could be this.

But anyhow, I'll live with the buzz for now until the next fluid change. Then it's torque everything down again time... printed all the eSI pages with torque specs highlighted this time.

ToniCipriani · « **Reply #38 on:** June 17, 2013, 10:29:18 PM »

Also an update on the two other noises, I'm more than inclined to believe the other noises are from the muffler. The rattling "drain sucking" noise happened a few times when I'm backing up, and when I let go of the gas. Then again when I rev and let go of the gas when the car is stationary. Didn't feel anything from the transmission and it definitely sounds like it's from the back of the car. Pop noise I actually heard it from the muffler once.

Maybe it's a sign saying I should get a Solo.

2kwk4u · « **Reply #39 on:** June 17, 2013, 11:24:50 PM »

Solo will only INCREASE burbling and popping. Most folks like that noise, though. I love the way my MBRP exhaust burbles, pops and snorts... but they don't make them anymore. Don't get me wrong, Solo makes perfectly awesome systems, too!

ToniCipriani · « **Reply #40 on:** June 17, 2013, 11:52:16 PM »

Quote from: 2kwk4u on June 17, 2013, 11:24:50 PM

Solo will only INCREASE burbling and popping. Most folks like that noise, though. I love the way my MBRP exhaust burbles, pops and snorts... but they don't make them anymore. Don't get me wrong, Solo makes perfectly awesome systems, too!

Oh no no, the exhaust burble I know, but the popping I'm referring to is like metal popping back in place when the system cools down, like metal snapping. Though it seems like that's normal in some cars.

Gentleman Jack · « **Reply #41 on:** June 18, 2013, 01:48:25 AM »

I don't agree with your letting it go until the next fluid change. Your putting yourself at risk. Driveline vibration is not right and potentially not safe. Get it fixed.

ChopTop · « **Reply #42 on:** June 18, 2013, 06:46:21 AM »

I agree, and still suggest finding someone who specializes in driveline vibration. This is starting to remind me of that ole saying da-nile isn't that river in Egypt.

ToniCipriani · « **Reply #43 on:** June 18, 2013, 07:10:22 AM »

Well the last resort would be taking it back to a dealer and cough up the hourly rate if it still can't be fixed at the fluid change. I've spent too much time running around over this diff issue already.

My mechanic reassured that it's safe to drive around. While she's my daily driver, I barely drive her still, at most just on weekends for the grocery run, and I'm only 1 tank of gas away from the fluid change, so in about 2 weeks to at most a month.

Gentleman Jack · « **Reply #44 on:** June 19, 2013, 03:28:43 AM »

I'm sure your mechanics insurance company will agree with him when they are paying for you car to be repaired, plus the cost of the three other cars involved in the freeway wreck. Thankfully, no one was hurt very badly.

ToniCipriani · « **Reply #45 on:** June 30, 2013, 11:02:02 PM »

Just an update...

I've managed to find the popping and the grinding noise at idle, at this point I'm 99% sure it's the muffler. It happened this time when I revved the engine, while the rev drops and continues for a while. I tried capturing a video but it didn't capture the noise very well, but it definitely from the muffler area. Other thing was that noise stopped when I opened and slammed the door shut to try to take the video...

As for the diff, I still haven't got it looked at yet, didn't have time to bring it back to the shop. The most interesting thing is though, lately the vibration has been dampened a lot, occasionally I'm completely smooth but other times the vibe right at 80km/h. I'm just passed the 500 km mark, going to do the diff fluid and retorquing everything. Hopefully it's just that and I don't need to go to the dealer.

Sly Bob · « **Reply #46 on:** July 08, 2013, 06:04:22 PM »

Maybe a trip to Solo is in your future. Glad you at least are on your way to putting this behind you.

ToniCipriani · « **Reply #47 on:** July 10, 2013, 09:15:43 PM »

OK... so I'm back from the mechanic. Fluid change done, but they were quite busy so I just visually re-inspected everything myself when it's on the lift. Everything seems to be fine. They told me the prop shaft was not touched at all, though GM manual says it should be removed. The fluid change did seem to be useful, as they showed me a LOT of metal filings on the fluid that came out.

Initially the Vibe is still there (pun intended), but again fluctuating, sometimes at 80 sometimes nothing.

So when I came home, out of nowhere came the idea for me to check the tire pressure. Kept in mind the tires are quite hot, I checked the pressure, but noticed one of the rear tire is WAY higher than the others, like 3-4 psi more. So I let some air out to equalize it with the others, this time the vibe is VASTLY removed. I can hard accelerate and it's smooth, though my rear view mirror still shakes a bit with a blurry image.

I'm gonna check the pressure again when the tires are cool and pump them back to 31 psi. If this cures it, I'm going to bang my head on the wall real hard.

ToniCipriani · « **Reply #48 on:** July 10, 2013, 09:30:41 PM »

And on the topic of tires... I came across these:

http://www.bimmerfest.com/forums/showthread.php?t=540692
http://www.bimmerfest.com/forums/showthread.php?t=548350

I happen to put on a set of V12s recently... maybe I should put my winters on to try...

Critterman · « **Reply #49 on:** July 11, 2013, 01:13:00 PM »

31 psi is way to high. 29 is the recommended pressure for our cars.

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Author Topic: Rear differential problems + other noises (Read 19549 times)