Hey, I got the 87 GTA, all stock but a Hooker catback. It recently started making a weird thump when you accelerate from a stop. It ony does it at less then 10mph or from a stop. It sounds like something jerking and you feel a kick coming from under the car near the passenger side, like right under their ****. If you idle it and very very slowly roll onto the throttle it won't do it. But if you step on the throttle like even a quick tap it will do it. I've tried reverse, and doing a hard downshift but like I said it only does it from a stand still or right off the line. Any advice on what it could be would be awesome!! Thanks guys

 

even though it doesn't do it on a hard downshift, I'd still have to say it sounds like a tranny mount.

 

Sounds like an absolute CLASSIC case of tranny mount failure to me! Fix it, it's only gonna get worse.

 

Yup, tranny mount

 

if its not the tranny mount (but it probably is) then it could be the motor mount on the passenger side, the way he described it under the passenger seat it could be the cat hitting the floor

 

Its probably the tranny mount. Change it...7$ at a parts store. Should be an easy fix.

 

this man knows these tranny mount things

 

I vote tranny mount, but look at your engine mounts and your u-joints while you're at it just to make sure.

 

Very funny j/k

 

Get a polyurethane trans mount. They are more expensive but will not require replacing again.