Quack_Addict
08-08-2007, 19:18
Please help me out here before I start throwing more parts at this transmission semi-blindly. The truck is a 1996 GMC with NV3500. A couple weeks ago, it started making a whining noise in neutral like throw-out bearings do when they go bad. When I would push in the clutch and wait a couple seconds for spin-down, the noise would go away. The noise is there with the transmission in neutral and in gear while the truck is moving. It was getting so loud that people stopped to stare while I drove through a parking structure last week.
I was so certain it was the throw-out bearing making the noise that I R&R'd the transmission on Saturday and installed a new T/O bearing. After about 6 hours of work, I started the truck back up and the noise was still there; changing the T/O bearing did not make the noise any better.
Does this sound like the transmission input shaft bearing? There seems to be excessive radial slop in the input shaft when I move it by hand, but I'm no transmission expert - it just seems like it has more play in it than it should. I removed the transmission again tonight and removed the input shaft bearing from the case. It spins freely but I can feel a little something in the bearing when I hold it on 2 fingers and spin it with my other hand but I don't feel any grit when I side load the bearing and turn it slowly. I'm not sure if the 'something' I feel is enough to make the "whah, whah, whah" sound the truck was making but I'm not loading the bearing or spinning it up at 700rpm like it does at idle in the truck.
The transmission was rebuilt a couple years ago and most of the internals (input shaft, counter shaft, bearings, etc) were all new. The transmission has about 40k miles on it since the rebuild.
I have been searching for an input shaft bearing and places that realize I'm not looking for a pilot bearing vary in cost from $75 (Car Quest) to >$110 (dealer). I can get an overhaul kit for the transmission with new bearings for a bit over $200.
Any ideas? Thanks for your thoughts...
I was so certain it was the throw-out bearing making the noise that I R&R'd the transmission on Saturday and installed a new T/O bearing. After about 6 hours of work, I started the truck back up and the noise was still there; changing the T/O bearing did not make the noise any better.
Does this sound like the transmission input shaft bearing? There seems to be excessive radial slop in the input shaft when I move it by hand, but I'm no transmission expert - it just seems like it has more play in it than it should. I removed the transmission again tonight and removed the input shaft bearing from the case. It spins freely but I can feel a little something in the bearing when I hold it on 2 fingers and spin it with my other hand but I don't feel any grit when I side load the bearing and turn it slowly. I'm not sure if the 'something' I feel is enough to make the "whah, whah, whah" sound the truck was making but I'm not loading the bearing or spinning it up at 700rpm like it does at idle in the truck.
The transmission was rebuilt a couple years ago and most of the internals (input shaft, counter shaft, bearings, etc) were all new. The transmission has about 40k miles on it since the rebuild.
I have been searching for an input shaft bearing and places that realize I'm not looking for a pilot bearing vary in cost from $75 (Car Quest) to >$110 (dealer). I can get an overhaul kit for the transmission with new bearings for a bit over $200.
Any ideas? Thanks for your thoughts...