my car makes a thumping type noise coming from somewhere between the rear and tranny...when i either hole-shot or just quickly "stab" the throttle this occurs...if i get on the gas qucikly but not suddenly flooring it it doesn't happen...i replaced the torque arm bushing because it looked like the arm was pulling out of it so i figgured it may have been smacking the floor pan...well the thumping still occurs...when it thumps i get a little wheel hop...i'll probably replace my tranny mount and see if that helps...anyone think something could be messed up in my rear? (torsen posi w/richmond 3.73's)...i know the posi unit isn't blown because the torsens make a metallic sound around every corner when they're shot....any help would be appreciated..i have one of the last races in the points series at my track this sat and i need to be there...thanks

 

You transmission mount is most certainly broken. I have broken two. It's quite common and they're simple to replace.

I'd stick with the stock replacement. I've heard that the Energy Suspension pieces are too tall (why they wouldn't make 'em stock height is a mystery to me). Perhaps there's another "unbreakable" replacement out there that fits properly, though.

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'87 IROC 5.7l TPI - original owner!

 

A couple choices over the plain 3rd gen tranny mount - I've had a bunch in the chicken so far.

a. ES. Yeah, when I used an ES with my stock torque arm/crossmember asm I had driveshaft vibration like heck... it altered the stock driveshaft angle when using the spacer plate that it comes with.

b. PROTHANE: available from summit. Stock height urethane tranny mount. Much harder than ES. I put this sucker in and had driveshaft vibrations too... unfortunately for me, I didn't know it was because I actually had an out-of-balance aluminum shaft at the time.... 'cause I done warped it!

c. 1LE/T-56 stock mount. Much tougher rubber mount. As for something like a '95 TA with a T-56... it's a lot bigger and is still rubber so it's a good compromise. I haven't really checked into it that much to know if it's the stock mount for their 4L60 auto's also... could be... I dunno yet.


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'89 Formula - Thunderchicken - 355 Vette L98/T-56/3.45 9-bolt/black/t-tops - the fun car!
'90 GTA - The GTA - 5.0 LB9/TH700/3.27 9-bolt/black/t-tops/tan leather - the cruiser.

 

thanks guys!...i'll go pick up a new tranny mount today and get it in either tonight after work or tomorrow...i'll let u know how it works out