vibration under acceleration
 

i was wondering if anyone has any ideas why i am getting vibration coming from under the car...feels like it is tranny related..i can feel it through the shifter..and when in 1st gear or 3rd under acceleration the shifter feels like it wants pop out of gear...the noise feels like thumping under the car from about the drvers seat back.

thanks

doug

Wheel bearing? Driveshaft? Do you get it in all gears?

yeah every gear under acceleration ...somthing thumping under the car...and i notice the shifter wanting to move back while in the 1st or 3rd and 5th gear...i was thinking drive shaft...maybe some kinda mount

Does turning left or right make a difference? that can show if it's driveshaft related.

i didnt think it was any louder when turning....just under acceleration.

Put it on a rack and see if someone can hear it more in the torque tube, tranny or rear wheel bearing area with an auto stethoscope. Also check the bell housing area just in case.

what and where is the torque tube?

the would the tube that connects the the engine input at the back of the bell housing to the front of the transaxle...and get the car to a Good shop.

im putting it on a lift tomorrow...ill look at everything...hopefully not too bad...i just need some ideas as to what to look for and where....thanks

This is a problem that many Porsche mechanics have a lot of trouble figuring out. It is your axles, especially if the vibration intensity changes a bit from time to time.

You should replace both of them (all 4 cv joints), otherwise the side you don't replace will put wear on the new axle quickly.

You can grab the axle shaft and try to twist it with weight on the rear tires (or the e-brake), if you can twist it at all (side to side play is fine), you need new axles.
Ahmet

this seems like it might be different ..i ended up repacking my bearings on the drivers side cv next to the exhaust last october at the track...so i know what that feels like..this seems like the thumping is under neither right at the seats but in the center of the car.

Doug

I second the CV joint thought. Paragon sells complete rear axles for cheap

You haven't lost a CV bolt have you? That would certainly throw things out of balance. I read somewhere that it's better to replace those bolts everytime they come out..... (?)

cars going on the lift this afternoon...hopefully i should know somthing soon...thanks for all the input guys

Doug

My problem turned out to be the rubber pucks that hold the exhaust to the hangers. 1 had fallen off and the exhaust started banging under excelleration. We ended up reversing a hanger to keep the puck on. Got all quiet after that ... just a sugestion!