In my '85 z28 305 TPI 700r4.... I was driving along a mountain road, I hit where the road had settled. It was like a curb, only not quite as abrupt. The left front of the car got to it first. Sounded like some part of the frame hit, though I can't see any damage. That was the only thing that hit, but it wasn't a nice tap, it was a good thud and bounce.

Imediatly after when I drive... I get a nasty vibration that seems to come from the Transmission. It only happens under a load, and while accelerating. At anyspeed, under acceleration that isn't grandma.

Possible Transmission mount? What else could it be? Drives straight, just painful to feel and hear. Thanks.

 

Transmission mount, wheel weight knocked off, cat hitting framerail or underbody, could be lotsa things,
Remember, it's hard to diagnose that from the driver's seat, noises often aren't coming from where you think they are.

 

It's not the wheel weight, cause it would vibrate all the time. Checked U-joints, replaced Transmission mount, and exhaust doesn't appear to be too close, but the whole system makes more noise than it used to when I bang on the tail pipe. It only makes it at 1500RPm then is subsides fast, then it makes it more prevalent from 2000-2500RPM. Thinking it's a drivetrain problem. The shaft was balanced and straightened 6 months ago, and I don't know how the bump would have made contact with it, or how it could have bent.

 

It may actually be your torque converter. A few months back a guy reported similar when he bottomed out hard going over a dip (or something like that). My donor car had been rear ended hard, the TC vibrates but only when actually powering the transmission (doesn't do it in neutral). It rattles pretty good, shakes the whole car.

I talked to a converter shop (not just a tranny shop), they said they had seen that.

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82 Berlinetta, orig V-6 car, now w/86 LG4/TH700R4. 2.93 limited slip. Cat-back from '91 GTA, ZZ3 intake, Accel HEI SuperCoil. AMSOIL syn lubes bumper-to-bumper. Daily driver, work-in-progress (LG4 w/'87 LB9 block, ZZ3 cam, ported World 305 heads, Hooker headers & y-pipe, 3" Catco cat & 3" cat-back).
57 Bel Air, my 1st car. '66 396, 9.7 CR forged TRWs, Weiand Action+, Edelbrock 1901 Q-Jet, GK 270 cam, Magnum rockers, Jacobs Omnipack, 1-3/4" Hedders & 3" Warlocks, TH400 w/TCI Sat Night Special conv & Trans-Scat shift kit, MegaShifter, 3.08 8.2" 10-bolt w/Powertrax, AMSOIL syn lubes bumper-to-bumper. Idles smooth @ 600 RPM in D. Best 15.02/95.06 @ 5800' Bandimere (corrected 13.93/102.4 @ sea level).