Indy Rev

I have been trying to identify an odd rattling noise when I accelerate. It does not rattle at high rpm or at cruising speed. At low rpm acceleration in almost any gear there is this rattling noise coming from the rear.

The noise is only under load. I cannot duplicate it by just rev-ing the engine. I also cannot find anything loose or shakeable under the rear.

any thoughts would be appreciated.

VirginiaF1

Can you attach a decent smartphone recording of it?
Or a short youtube for diagnosis?

Indy Rev

ill try and get a sound clip tonight when I get home.

My wife always hates it when I make her lean out the back of the hatch with a video camera. I told her its better than strapping one of the kids to the bottom of the car though.

John_AZ

Porsche had a tech info page that the rear shock mounts need to be retorqued to stop a rattle.
or
Loose/bent muffler heat sheilds
or
Bell housing bottom dust cover (engine side held by 2 bolts)
or
rear linkage rattle due to worn intermediate shift lever on top of transaxle.
or
????

John

Indy Rev

or?
or?
or?
Thanks John. ill check those out. shift linkage was one of the things I was going to check in the morning. how can you tell if the tt bearings are going out?

John_AZ

TT bearings can cause a vibration/noise in the center tunnel area at road speeds.

Go on a back road at 35MPH, press the clutch in and rev the engine. Do you feel a vibration??

If no vibration====really good news! PP and FW are balanced!

Now let the clutch out and try to feel a vibration. If you feel a small vibration/noise, it could be the TT bearings.

To further prove it is the TT bearings and not the transaxle, unbolt the transaxle coupler and slide it all the way back (rear).

With the drive shaft and transaxle separated. Start the car and try to get a vibration/noise from the TT.

If no noise or vibration, the TT bearings may be good. But now you have to find out why the transaxle makes noise. Next Chapter.

GL
John

Jay W

Have you checked the CV axle bolts? Mine made noise on slow speed acceleration and 3 bolts had sheared and only 2 were left holding the axle in.

Indy Rev

thanks John and Jay for the input. I didn't get much of a chance this weekend to find the noise issue. my a/c , alt belt blew on my way home sat morning and I found that the bolts holding the a/c where broke and missing. so I took care of that.
I did try the 35mph vibration test and I get nothing. its as smooth as can be. I can't actually duplicate the noise at all just reving the engine. there is absolutely no vibration associated with the noise.

I will look at the other suggested items this week

thanks