New LS1 Owners - Newbie Tech - Trans Mount Bad?

when i have it in D my car doesnt vibrate much but once i drop it into 3rd it starts to vibarte bad like im running over a bad patch of road. could a bad trans mount be what is causing this?
the car has 121k on the clock

maybe, change it.

could be either a trans mount issue or a trans issue. i suggest you change the trans mount first. get an energy suspension mount for $20

could be either a trans mount issue or a trans issue. i suggest you change the trans mount first. get an energy suspension mount for $20

no, get a factory rubber one unless you have poly motor mounts. this guy is trying to get you a broken tailshaft.

Its your tranny, i have the same problem... needs a rebuilt.

Check your universal joints and your drive shaft too. Mine was outta balance and gave me a hella bad vib at high RPM'S.

first just look at your mount, you can easily jack the car up (or have a lift take it up like me) and just look at the mount and see if its cracked, loose or damaged. and if it is go with a stock rubber mount. DO NOT GET A POLY TRANNY MOUNT, I REPEAT NO POLY MOUNT. if you do this will put all the engine vibrations into the tranny since the motor mounts will be softer.

it could also be your ypipe banging in the upper rpms as well. take a look at that.

Sounds like a tranny issue. There shouldnt be a difference in vibration between D and 3. Doesnt hurt to check the mount though.

Sounds like a tranny issue. There shouldnt be a difference in vibration between D and 3. Doesnt hurt to check the mount though.

my 98 z28 does the same exact thing. i have a poly tranny mount and 373's. i was kinda hoping it was a driveshaft issue not the tranny.

It can be a number of things. Tranny mount...ds...tranny.

I have a level 2 performabuilt trans and 3000k stall with the same problem. I'm still searching.

I just talked to Frank at Performance trannys about a hour ago LOL about my new Rossler stage (3) 4L60 making a clunking noise when it goes from 2nd into 3rd,,, and he said alot of trannys do this because once into third EVERTHING inside the tranny spins together in one direction (that quick) and is why its like a clunk Now, a vibration may be something else? Ide try a new mount first and call Frank at Performace trannys! Hes on here all the time in the tranny sect and is VERY cool about helping guys out with questions
Good luck Barnat

get a t56 that'll fix it