My 82 Berlinetta is making a scary sound. I'm pretty sure its coming from the diff, when I punch it at low speeds or drop the tranny into drive at engine speeds even slightly above idle there is a loud thud. I can feel it through the whole car but everyone in the car including me say its from the back, and if I pulsate the gas I can get it to go thud, thud, thud. The car is an original V6 auto, but I swapped a stock 305 and TH350. I never got to drive the car when it had the V6 because it never ran so I cant say if the noise is new or not.

I've been told it could be posi slap(doubtful because i dont have a posi ) , or possibly sloppy side gears in the diff, or maybe the diff is on its way out. It was lady driven prior to me owning it and fluids weren't kept in good shape(she ran the V6 out of oil ), maybe the same fate was decided for the diff. Im not sure how many owners it had but the car doesn't look abused at all, very nice shape.

Anyone have any ideas what this could be? Thanks A Lot

 

trans mount or torque arm bushing

You say it has a T-350; if that's true, something must have been done to hold the torque arm in place, since T-350s didn't come in that car, and there's not one made that will fit; I'd look real hard at that area.

If it has a torque arm bracket that bolts directly to the trans, it's a T-200, not a 350. 200s also have the word "METRIC" stamped in the pan, 350s do not.

 

I"m gonna say it's probably the trans mount. When mine went bad, I could have sworn it was coming from the rear.

 

yeah id say take a look at the mounts also, also for anything loose..