My 56k 96 z28 auto is making a clunking grinding noise and trembling when I hit the gas in reverse. It rolls smoothly in reverse with momentum.

On the highway it sometimes (not always) downshifts and up shifts unexpectedly. But smoothly.

Are these related? Do you think the trans is going?

 

any ideas?

 

Is it completely stock? You should add a sig with all your mods if you have any. I know after I installed my long tube headers, I think the steering joint vibrates against the headers sometimes and actually caused the car to shut off in reverse a couple times, hasn't happened lately, just right after I did the install. Maybe that helps.

 

Driveshaft, LT pacesetters hit the chasis under a load.

have you checked your trans fluid level? when was your tranny drained and filter replaced?