1982 gmc 6.2 with custom built 700R4 tranny
I have a grinding noise in Park, neutral, drives, but goes away when shifted into reverse or low. Goes away when steping on it , comes back when just holding speed, Goes away when I back off. when I slow down to stop and brake rather hard it goes away. But returns when shifted into park , have changed trans fluid <like new> pulled fly wheel cover clean nothing there.
Tranny shifts great no slipping. Any ideas ???

hmm,
maybe a SOUNDFILE would be great;)
A grinding noise and NOT the flywheel...converter... perhaps a loosen nut on ac-cover?


mfG
Sonne

A cracked or bent flexplate[flywheel] will cause the torque converter bolts to rub on the cover on the bottom under load. I had a 86 k25 with a 35o gas t400 that would break the flexplate every 5-6000 miles. It made alot of grinding noise under load but would quiet down when up to speed

my flywheel (flexplate) cover is plastic.. it started after having the air conditioner compreeor replaced ??

To know if it is related remove the compressor belt and start the engine . dont let it run too long because if you have the serpentine model you are removing you water pump as well . but for 20-30 second periodes no probleme

At the same time have a look at you crankshaft damper . it may cause noise

Ed

1. When the transmission is shifted into Park, NOTHING is moving in the transmission except the torque converter.

2. Use a stethoscope or sound rod (long screw driver, steel or wood rod, etc.) and place one end on different parts of the engine while holding the other end with your thumb against your ear. The sounds travel up the rod and you can tell by the intensity, where the noise is coming from. Most likely it is your A/C compressor, especially if it is rebuilt, rather than a new one. Caution, don't get the rod in the fan belts.

thanks guys, I have run it on hoist noise seems to be more pronounced at fly wheel cover.
has regular belts.
air comp not noisy