Jas Knight
New member
My 96 Suburban with a 6.5L diesel (267,000 miles on it) is having a bad vibration problem at idle only. Idle speed is normal (650 rpm same as its always been). harmonic balancer and crank pulley are in good shape no cracking in the rubber. Sometimes the vibration isnt so bad, and other times you think the truck is gonna fall apart its vibrating so bad. I am thinking motor mounts since it has so many miles on it and since its a 96 but i'm not sure.
The truck has for years had a thump at 50mph or so when you let off the throttle and again when you get back on the throttle especially if either motion is sudden. Both of these make me think trans and or motor mounts. What do you guys think?
Problem only happens at idle, not while driving (unless i happen to be coasting at less than 30mph when the engine speed falls back to idle). This eliminates the driveline and ujoint problem. The driveline also has never been removed from this truck, its all mechanically pretty much original with very few exceptions.
The truck has for years had a thump at 50mph or so when you let off the throttle and again when you get back on the throttle especially if either motion is sudden. Both of these make me think trans and or motor mounts. What do you guys think?
Problem only happens at idle, not while driving (unless i happen to be coasting at less than 30mph when the engine speed falls back to idle). This eliminates the driveline and ujoint problem. The driveline also has never been removed from this truck, its all mechanically pretty much original with very few exceptions.