sleeperstyle

iTrader: (4)

i just installed a prothane transmission mount and a adj panhard rod. i adjusted the rod to the stock rod's length, put it on and tested it out- no problems there.


i put the polyurethane trans mount in. apon starting the car i instatly feel the solidness of the mount because it vibrates the car more.

my question is- at partial and full throttle the car vibrates, sometimes violently, like from the driveshaft/transmission area. all of the bolts are TIGHT btw. is this NORMAL??? if a trans mount makes the car vibrate like hell while driving down the road im putting my stocker back in. i seriously could see this much vibration setting off the knock sensor or something.

##edit

took it for another drive. it does seem that it is just how stiff the mount is making it vibrate. my car is far from a smooth cruiser now though but if this is normal with the poly-mount then so be it..

sleeperstyle

iTrader: (4)

wow- nobody even told me to search! i did search and i found similar complaints about the trans mount and it's vibrations= so i ended up taking the poly-trans mount out. i HATED it in, feelt like the car was gonna fall apart.

thanks everyone - cheers

more carbon

RACE CARS ONLY!!! those things are stiffer than a saturday night with the girlfriend!!!!

99-LS1-SS

You could have a out of balance drive shaft. I put a poly transmission mount in and my car vibrated. I got my driveshaft balanced and it went away.

Try this, drive your car at around 50 mph and while you are driving put it in neutral and see if it still vibrates or gets worse. If so it is probably your drive shaft.

Cheatin' Chad

iTrader: (3)

Make sure the pinion and trans tailshaft angles are still witin spec.

I drive everday with a poly trans mount. It's not THAT bad. It definitely takes some getting used to though.

jaberwaki

stock rubbers will often time hide what polys show like a sore thumb.. if it vibrated so bad that you could not stand it(i am taking for granted that you have a pair) then chances are that the polys where showing you a vibration in your drivetrain that you could not detect b4.
the drive shaft is a good place to start.

sleeperstyle

iTrader: (4)

driveshaft= stock steel ****** . guess that has to go huh?

i noticed that the poly mount is about 1/4 inch higher than the stocker (i measured). this would put the transmission up 1/4 inch higher and throw off the driveshaft/tailshaft angle.? that was my thought at least, i was thinking about getting 4 - 1/4" longer bolts and some washers to shim the whole trans cross-member to retain the "stock" driveshaft angle..

how do i go about getting a driveshaft balanced? (when i get a aluminum one) or is it worth it to go new through gm since it is like 220$ for a new aluminum one. how do i set the pinion angle? im know i could search but while we are on the subject...

i could completly take the engine vibration that it threw off- it was kind of cool and made the car feel more alive, but cruising at partial throttle it was obnoxious and at wot it was even worse.

Cheatin' Chad

iTrader: (3)

This is a good place to start

jaberwaki

do a search on pinion angle, i seem to remember someone did a whole right up on it.


and any place that sells driveshafts will be able to balance it for ya

jimmyblue

iTrader: (11)

You want the tailshaft at the same height as before
(presuming the factory setup was right). People
sometimes have to either leave off shim plates,
grind stuff, etc. to get it right.