Rumbling sound

[JonW]

I've changed quite a bit on my car, and did it all at once: 4.10s, torque convertor, mufflers. Now, when I roll to a stop, as soon as the speedo needle drops past 18 mph, I hear a subdued rumbling or growling noise coming from the rear of the car. It can always be heard at exactly 18 mph, whether I am coming to a slow stop, or a quick stop. It's not a banging noise like a muffler or exhaust pipe hitting something, it's more subdued and not metallic. I also hear it on occasion during light acceleration, but it's usually around 22 to 25 mph on acceleration.

Could this be in the new gear set or in the TC? I really don't think it's in the exhaust system.

[SamF]

I've changed quite a bit on my car, and did it all at once: 4.10s, torque convertor, mufflers. Now, when I roll to a stop, as soon as the speedo needle drops past 18 mph, I hear a subdued rumbling or growling noise coming from the rear of the car. It can always be heard at exactly 18 mph, whether I am coming to a slow stop, or a quick stop. It's not a banging noise like a muffler or exhaust pipe hitting something, it's more subdued and not metallic. I also hear it on occasion during light acceleration, but it's usually around 22 to 25 mph on acceleration.

Could this be in the new gear set or in the TC? I really don't think it's in the exhaust system.

I'd have the installer crack the rear open to have a look asap.

[JonW]

I took it out and drove it a while again tonight. I dunno.... it might be exhaust. It also does it going around a right hand corner sometimes and at certain rpms under light throttle.

[SamF]

If you suspect the rear at all I would have it looked at before driving it much. The real problem with rear end issues is that once you start hearing it the damage is well underway :mad2: and can get much worse in a short period of time/miles.

Let us know what you find.

[Marauderjack]

Pull the magnetic fill plug or the differential......If it has any bright colored metal on it you can bet the axles and bearings are toast!!!:argue: Normal is a small amout of graphite (dark powder) looking stuff......:cool:

My 2000 CV developed a "Wump....Wump....Wump" sound that I thought was a badly scalloped tire.....pulled the plug and about 4 inches of metal flakes were on it!!!:mad2: It looked like a friggin bird wing??:confused: New axles, bearings and seals and she's now working on her 4th 100K with the second owner!!:beer:

Good Luck.....Let us know what you find!!

Marauderjack:burnout:

[RCSignals]

Pull the magnetic fill plug or the differential......If it has any bright colored metal on it you can bet the axles and bearings are toast!!!:argue: Normal is a small amout of graphite (dark powder) looking stuff......:cool:

My 2000 CV developed a "Wump....Wump....Wump" sound that I thought was a badly scalloped tire.....pulled the plug and about 4 inches of metal flakes were on it!!!:mad2: It looked like a friggin bird wing??:confused: New axles, bearings and seals and she's now working on her 4th 100K with the second owner!!:beer:

Good Luck.....Let us know what you find!!

Marauderjack:burnout:


working on 400K ? :bows:

What was the mileage when you found the rearend had gone?

[chader]

I took it out and drove it a while again tonight. I dunno.... it might be exhaust. It also does it going around a right hand corner sometimes and at certain rpms under light throttle.
Any chance friction mod. was forgot??

[Marauderjack]

working on 400K ? :bows:

What was the mileage when you found the rearend had gone?

It was at 175K or so but had been doing it awhile......I thought it was tires all along??:confused:

[Raudermaster]

Jon, no worries. Could it be your exhaust "de-toning" when your car shifts back into 1st? ;) I mean, you do have Borla's on there.

[Drock96Marquis]

Sounds a lot like a shot axle bearing.

Do you see any diff fluid or grease on the inside of your rear wheels?


Could also be too much pinion pre-load (which would be heard more at low speed)
No friction modifier wouldn't cause the noise to be ehard with straight line deccel.

Is it louder after cruising on the highway some?


Have it looked at ASAP.

[RaceLegend79]

To me it sounds just like what my 97 CVPI sounded like after it had gotten stuck in the mud and then got driven on a long highway trip. I needed a whole new rear end. But mine sounded horrible when I shifted from park to any go gear or from D to R or vice versa. But I definitly remeber right turns sounding horrific. If I were you I would take the advice of everyone else and either have it looked at at your home or have it towed to the nearest shop to have it checked out.