hi, my girlfriends truck is a 1998 gmc 1500 4x4 5.7 its got about 130,000 miles and is stock.

when driving it makes a very very loud metallic whining noise. i think its coming from the tranny. it started one day when we were driving on the highway for awhile and felt a few wierd thumps from under the floorboard, then while slowing down on the on-ramp it whined as we slowed down. ever since then its gotten louder and louder.

it only happens while driving, no matter what speed your at, its whining.

plus, (this has been going on for alot longer than the noise). the truck pulls very hard and doesnt slip, but when you give it 1/2-3/4 throttle (or full throttle) the motor just sits at 3-4 grand and the truck doesnt accelerate at all, then when you let off a little, it feels like it catches and takes off (low rpm, but pulling hard)

Is this related?

could it have been the rest of the clutch particles breaking off the bands and the the bands are bare metal?

i have no idea what trans it has. if its a 4L80E OR 4L60E. im not sure. is there any way of knowing?


thanks for any help

 

You have the 4l80e. Try putting your truck on some jack stands and then put it in drive and see if you can hear it whine from the either the differential or the transmission itself. Sounds like the differential is messed up. But thats just a guess. If its coming from the transmission then check your fluid levels and drop your pan and see if you notice any metal particles on the bottom of it.