Help! Drivetrain noise during decelartion/coasting while in gear?

[360glitch]

I just got the new transmission is in the car (broke two teeth off of the intermediate shaft) and it shifts like butter but our drivetrain noise still remains. When I originally discovered the noise I looked under the car and found one of the rear axles had a torn boot and had slung grease everywhere. I took the cv axle to a shop to rebuild it and the guy inspected it and said it looked fine. They put new boots on it and gave it back to me. ($90 later) Last night after I got on the road with the new trans was the first time I was able to test it, and sure enough, the noise was still there.

The noise occurs during the following conditions:

- Car is decelerating and/or coasting
- Car is in gear and clutch is NOT pushed in

Push in the clutch and it goes away. Give the car any gas at all and it stops making the noise. We are supposed to be headed to the NC Mountain Meet meet on Thursday, and time is running out. Any ideas?

 

[92AWDHX40]

sounds like the internals of the tranny.

 

[360glitch]

sounds like the internals of the tranny.

Definitely not the problem. The problem started last week with a different transmission in the car. A new one from TRE was just installed this weekend. Thanks though.

 

[92AWDHX40]

Sorry, i missed that, team rip does well got me one too. MMM I would look at everything in the area.

 

[1995gsx20g]

it could be your transfer case, carrier bearings or even rear differental.

where can you hear the noise from?

if you can hear it while moving slowly, open your door and listen next to a wall.

is it the same exact noise as before?

brand new gearsets have to break in and may be noisy when new.

what condition is the clutch in? what kind?

does the noise change while going up or down a hill?

what kind of shape are your motor mounts in?

my guess is the carrier bearings tho..

i just reread your post again. does it make this noise while idling?

 

[4pistons]

Do you have an aluminum flywheel with an aftermarket clutch? It could cause a decell vibration. Read these from some posts I made years ago:

This is a very common issue with the lightweight flywheel/ heavy clutch mod. It happened to me too. From talking to, and grilling, both ACT and Fidanza I am convinced it is a balance problem with the clutch. Fidanza recommends ALWAYS balancing the clutch and flywheel together as an assembly. Don't rely on the flywheel and clutch being balanced individually.

Fidanza claims they have seen major imbalance problems with clutches (not just ACT) and ACT claimed theirs are "good". I'd believe Fidanza first because as they've said "How long would we be in business if we sold out of balance flywheels?"

A small clutch imbalance with a stock flywheel probably wouldn't be noticed but it shows on a lightened one. Especially during deceleration. I'd be curious to know if someone who has had theirs balanced has any vibration issues. I plan to get mine balanced next time the tranny is out. Until then I've learned to live with it.

Rick - '91 GSX

As said before I think this problem only occurs when unbalanced clutches are coupled with a lightweight flywheel. When I asked ACT if the clutches were balanced they wouldn't answer me directly. They said they were "good" and they shouldn't be the problem. That isn't very reassuring to me. Whereas Fidanza emphatically said their flywheels were balanced precisely.

Rick - '91 GSX

That was back in '05 and I still haven't pulled the trans yet! I've just lived with it!

Rick - '91 GSX

 

[90on35psi]

I'm pretty sure I have the same noise that you're talking about... same symptoms. Just a strange noise from what sounds like the driveshafts only while decelerating by motor brake. I just coast now From looking around underneath the car I place the blame on 21 year old carrier bearings.

 

[94awdcoupe]

This issue is from removing the spring center disc. Very common problem with twin plate clutches. Whats happening is the engine harmonics are transferring through trans and into the drivshaft where the vibration is heard. light weight flywheels also pronounce the issue and may even cause some noise with spring center clutches. . heavier flywheels absorb some of the energy. Its not a clutch or flywheel imbalance issue.

 

[ReYnd]

Carrier bearings. More specifically, the rubber insulators. My rear one was torn badly, and the front was looking pretty rough. See if yours look like they could stand to be replaced. If you want to go super cheap, you could try the "Driveshaft Thump" fix from the VFAQ. I just replaced them to have an excuse to repaint it.

 

[1997_GSX]

Totally normal, my car does it too along with everybody elses car with lightweight flywheel with a puck clutch.

 

[ErikTande]

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The noise occurs during the following conditions:

- Car is decelerating and/or coasting
- Car is in gear and clutch is NOT pushed in

Push in the clutch and it goes away. Give the car any gas at all and it stops making the noise.

I have this EXACT same problem. There is a rattling / slight grinding type noise when coasting in gear.

Is it the carrier bearings causing this? Is it damaging anything and should I fix it immediately? Or is it just noisy and not really hurting anything?

 

[360glitch]

I'm embarrassed to say that my problem just ended up being wheel bearings. FYI.

 

[ErikTande]

I'm embarrassed to say that my problem just ended up being wheel bearings. FYI.

Thanks for the info! Would wheel bearings only do that when the car is in gear though? Maybe it's my problem too.

 

[AWD Night rider]

Wich wheel bearings front or rear?