Metallic "Clunk" Sound

[Ray K.]

Whenever I put my 82 into gear (drive or reverse), there is a loud "clunk" from the underside of the car, and the car jumps slightly forward or backward as the case may be. I don't know if it comes from the differential or transmission. I am leaning towards too much backlash in the pinion/ring gear; then again, the backlash could be correct, and the transmission could be dumping too much kinetic energy into the drive shaft over too short of a period. Other than that, the car runs fine. I don't know much about automatics. Is there an oil pressure adjustment on the transmission that would reduce this problem, or should I open the rear end and adjust the backlash? The car has a GM 350 crate motor, TH200-R4 transmission, and Dana 40 rear.

[IndyJimW]

As a mechanic the first thing I would look at is the u-joints, then the transmission and engine mounts. Engine idle speed may be too high.

Good luck

Jim Wood

[

[Ray K.]

As a mechanic the first thing I would look at is the u-joints, then the transmission and engine mounts. Engine idle speed may be too high.

Good luck

Jim Wood

U-joints - now why didn't I think of that.... Thanks for the suggestion!

RayK

[IndyJimW]

Thats why I make the those big mechanic bucks. lol

Jim Wood

[ernier]

Did this start happening after a change in engines or carburetors?

If the idle is too high you will get a rough engage.

Does the transmission take a long time to shift out of 1st gear under light acceleration?

A loose pinion yoke.

U joints will make noise but usually produce vibrations when you're driving also. Any roughness on accel or decel?

Usually it's the simple things so try reducing idle 1st...easiest and cheapest.

ErnieR

Whenever I put my 82 into gear (drive or reverse), there is a loud "clunk" from the underside of the car, and the car jumps slightly forward or backward as the case may be. I don't know if it comes from the differential or transmission. I am leaning towards too much backlash in the pinion/ring gear; then again, the backlash could be correct, and the transmission could be dumping too much kinetic energy into the drive shaft over too short of a period. Other than that, the car runs fine. I don't know much about automatics. Is there an oil pressure adjustment on the transmission that would reduce this problem, or should I open the rear end and adjust the backlash? The car has a GM 350 crate motor, TH200-R4 transmission, and Dana 40 rear.

[Ray K.]

Did this start happening after a change in engines or carburetors?

If the idle is too high you will get a rough engage.

Does the transmission take a long time to shift out of 1st gear under light acceleration?

A loose pinion yoke.

U joints will make noise but usually produce vibrations when you're driving also. Any roughness on accel or decel?

Usually it's the simple things so try reducing idle 1st...easiest and cheapest.

ErnieR