chief_shotts
Full Access Member
- Joined
- Nov 29, 2021
- Posts
- 50
- Reaction score
- 38
- Location
- beaverton, OR
- First Name
- edgar
- Truck Year
- 1986
- Truck Model
- k30
- Engine Size
- 383
The truck is a 1987 crew cab k30. 383 stroker, turbo 400, np205, d60, gm14bolt. The issue is Ive been experiencing some vibration at 3000+ rpm. I think it comes on sooner than that but the vibration becomes evident at higher rpms. The vibration feels like it is coming from a rotating assembly because of the way it surges and increases with the speed of the engine. Id also note there is a odd sound that accompanies the vibration. Something like a out of balance washing machine with marbles in it but very subtle... hopefully that makes sense... its not a grinding noise exactly but its not not a grinding noise...
The engine, trans, and tcase are fairly new (couple thousand miles) all rebuilt by a reputable shops. The rear end/ front end are also rebuilt. The front driveshaft is being rebuilt as we speak and the rear driveshaft was rebuilt, balanced, phased.
I thought maybe it was the driveline angles on the rear end. I adjusted so that the rear pinion angle was parallel or close to Parallel with the tcase output. This had zero effect.
I removed both driveshafts and revved the engine in gear while parked in the driveway... I could still feel the vibration and hear the noise.
I have the ability to remove the floor over the trans tunnel.. so i did.. and with the trans in nuetral and the transfer case in gear i spun the output yoke and this when i discovered a strange noise coming from the transmission that is very similar in nature to the sound i hear at high speeds (sounds like theres marbles in the trans)+ a whining noise. Please watch the video attached and listen for yourself. Does this seem odd to you guys. Could there be something wrong in the transmission and that is what is causing the vibes.
I'm leaning towards bringing the truck in to the trans shop to have them look it over. But I am a bit weary of going to the same shop as they built it to begin with and Ive put very little load/ miles on the trans since rebuilding it.
The engine, trans, and tcase are fairly new (couple thousand miles) all rebuilt by a reputable shops. The rear end/ front end are also rebuilt. The front driveshaft is being rebuilt as we speak and the rear driveshaft was rebuilt, balanced, phased.
I thought maybe it was the driveline angles on the rear end. I adjusted so that the rear pinion angle was parallel or close to Parallel with the tcase output. This had zero effect.
I removed both driveshafts and revved the engine in gear while parked in the driveway... I could still feel the vibration and hear the noise.
I have the ability to remove the floor over the trans tunnel.. so i did.. and with the trans in nuetral and the transfer case in gear i spun the output yoke and this when i discovered a strange noise coming from the transmission that is very similar in nature to the sound i hear at high speeds (sounds like theres marbles in the trans)+ a whining noise. Please watch the video attached and listen for yourself. Does this seem odd to you guys. Could there be something wrong in the transmission and that is what is causing the vibes.
I'm leaning towards bringing the truck in to the trans shop to have them look it over. But I am a bit weary of going to the same shop as they built it to begin with and Ive put very little load/ miles on the trans since rebuilding it.
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