this is rpm related... but only in 1 specific gear....

im pretty sure its 3rd, MIGHT be 2nd tho.... i need to go check


anyway on mild accleration from a stop or slow roll... goin up thru the gears.... everythings cool... nothing speed related happening nothing.

except for this one gear ONLY between about 2200 and 2500 rpms... theres a bad vibration... when i say bad i don't mean like pull over to the side of the road immediately, bad. but bad enough for say a passenger to notice after it happening a few times... a car guy... the first time... and just inquizitivly ask "what was that?"

to which i have no answer

 

sounds like you're hitting the harmonic frequency of something. possibly the driveshaft.

wold be worth checking out the u-joints as well.

what gears do you have? if you have the 2.73s didn't you get the steel driveshaft??

 

if it was the driveshaft, it would do at at different rpms in different gears, would it not? this is the ONLY time it does anything like that...


and no... far as i know all ls1's have aluminum driveshafts.... mine is. but all ws6 a4's came with 3:23's

 

yeah...that's true...

not sure man..

but...
"far as i know all ls1's have aluminum driveshafts"

NOPE...the 2.73 equipped cars had the steel. i thought they were all alum untill i was corrected.
ask Robvas his 02 z28 had a steel shaft and was auto w/ 2.73s