Hey, I'm pretty new to frnt engine/rear drive cars(drove imports for a while, musta' been the concussion). Anyway, whenever I floor the pedal at a stop i.e."Launch" I hear and feel a large "thunk" under my car. Sometimes it's under the console(u can see the shifter move), and sometimes its by one of the rear wheels, but never both at the same time. I can never burn my tires either. Kinda new to the drivetrain so be descriptive please if u have any ideas. thanx

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14X3 o.e., functional formula hood(for sale in future), uhhh..., umm...

Am I the only person who believes a car has feelings, emotions, and a soul??

 

Could be a worn tranny mount, crossmember banged up somehow... and by the wheels its probably just one of the mushy soft rubber bushing ... you can replace those with urethane parts if you want to, better than the rubber crap

other than that, i dunno everyone else probably has more ideas than me

 

Definently look into the transmission mount, and while you're down there check the torque arm bushing, that could be going also.

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--Steve S--
1984 Trans Am 305 LG4, 5 speed Daily Driver, Flowmaster 80 Series
Holley 600 cfm & vacuum advance Soon: Edlebrock Intake & TES

 

I would say that it is the torque arm bushing.

 

Its your Transmission mount. Jack your car up, crawl under it, and you will see the mount. If youre lucky, the bolt is loose. If you need to R&R (Remove and Replace) the mount, put a jack under the transmission, remove the 4 bolts holding the tranny crossmember, then the bolt holding the member to the tranny. The mount will still be on the transmission. Remove the two bolts.

My favorite line "Installation is the reverse of Removal"

Hope this helps.
Clayton

PS It is very easy to do.

 

I've seen this happen a dozen times. Trans mount. Sometimes it's obvious, sometimes not so obvious to the eye. Get a polyurethane mount from Summit. If you like playing with your car, it's a great investment, since they're made differently than stock mounts (so they don't tear).

 

There's no question... TRANNY MOUNT. Not to worry, they are cheap to replace. Cheap enough that you should pick up two just to have one left for a spare. Pretty easy to replace too!

 

I just had the same problem, My tranny mount was sheered in half. $6.49 from advance auto and about 15 minutes later it was good as new.

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Flowmaster 80 series muffler, K&N Open Element cleaner, Subframe Connectors + a lead pedal foot . See my baby @
http://oursportscars.homestead.com/home.html