CARGUY

I have a 97 m6 Z28 and am starting to wonder if the f-body will always have a driveline vibration no matter what. I originally had a 1LE alum driveshaft and came to find out after having gears installed that the end of the shaft was messsed up and was out of balance. So, I ordered up an LS1 alum shaft from a salvage yard. Put it in and it was better but the vibration was still there. Finally, like many others, I decided a couple of days ago to remove my ES tranny mount and threw in my friends (good condition) LS1 stock tranny mount. It was definetly an improvement but at around 80-90mph on the highway I still have a noticible vibration under load. Oh, its not the wheels, I had them dynamically balanced recently. Please help!

Dmx4ever3

i have the problem too
i got a 99 ss alm. ds and it got better i also have a poly mount in but its still a little shakey

CARGUY

If you still have the poly mount in (Energy Suspensions?) take it out and put in a stock rubber mount. Thats part of your problem.

By the way, I talked to Greg over at ES and he says they may possibly have the replacement mount ready middle of next month. It been delayed a few times, so I'm not holding my breath.

twells

u joint???? could it be that

CARGUY

WOW! She sank fast!

Any one have any ideas for me?

CARGUY

Not sure, I spose it could be? Is your car completely smooth at those speeds?

twells

yup,

mine is just fine. i had a friend who had a bad vibration but it was at 60 mph. she replace her driveshaft and a bunch of other this and it ended up being her u joint. that is what i would try if i were you

thomas

Dmx4ever3

i replaced my engine mounts that did nothing waste of money but..... when i replaced my ds with an alm. i took out my old one and found that my u joints WERE BAD.. so that is what it could be

CARGUY

Thanks guys, I'll check the U-joints.

Zepher

My brother has a similiar problem on his 96 T/A. We though it was a bad axle, so replaced both of them, no go. redid all the bearings and gears, still no go. Put in a virgin 3.42 geared rear end and no more vibrations.
could the axle shafts be out of whack and cause the vibration? I believe that they are only pressed into the pumpkin.

quicksilver97ta

I have been through all of the above basically and spent extra money having an LS1 ds cut and rewelded more accurately on center. Still dont like going over 80mph due to vibes. I think the only true fix would be a carbon fiber ds. You gotta figure in 6th (.5 OD) if I'm cruising at 2400 rpm, the ds is doing 4800 rpm, at 3k the ds is 6K Thats a large object to be turning that fast. Only other option is to put a hiway gear in the rear.

CARGUY

hmmm, assuming my U-joint is bad, could that mess up my driveshaft or anything else??