Truck Vibrates At 40 And 65

k5-silverado · January 30, 2008

Ok, so here is the deal, My 95 silverado (150,000 miles) has a strange vibration in the 40mph and 65mph range. I just had the transmission flushed in december, do you think this could be a problem, or do you think it could be something less serious problem such as u-joints contributing to the vibrations? any help would be nice.

Zembonez · January 30, 2008

Welcome to the site Eric.

With vibrations, ya gotta start with the basics. Pull the wheels and tires and have them professionally balanced - paying very close attention to any that are out of round or bent. Tread that is severely worn or irregularly worn can cause weird problems too. If they all balance out and are in good shape, try varying the air pressure 5 pounds up or down and see if there is a change.

THEN I'd start looking at shocks, Ujoints, etc. A trans flush shouldn't have anything to do with it.

Most (but not necessarily all) of these issues are going to be tire and wheel related.

k5-silverado · January 30, 2008

i'll have to look into that. i just got new tires 4 days ago, some Jetzon trailcutter R/T's. I used to have a Zr2, but i sold it to get a bigger vehicle. on the Z it was a u-joint that was going bad. I know the tires are balanced, i neglected to get an alingment though. I guess i should do that. But in those speed ranges i mentioned , it only happens when i lightley press the gas pedal. It's a rumble/vibration. I've never experienced something like that before, that's why i was wondering if it could have been something with the newly flushed tranny.

conrad1995 · January 30, 2008

i'll have to look into that. i just got new tires 4 days ago, some Jetzon trailcutter R/T's. I used to have a Zr2, but i sold it to get a bigger vehicle. on the Z it was a u-joint that was going bad. I know the tires are balanced, i neglected to get an alingment though. I guess i should do that. But in those speed ranges i mentioned , it only happens when i lightley press the gas pedal. It's a rumble/vibration. I've never experienced something like that before, that's why i was wondering if it could have been something with the newly flushed tranny.

Is the truck trying to shift out of over-drive or between gears, does it stop if you press on the gas a little harder?

Draenor · January 30, 2008

What are the RPMs at both speeds? Usually a out of balanced tire will vibrate at high speeds.

k5-silverado · January 30, 2008

yeah, it stops when i press on the gas a lilttle harder. but it's only at those speeds. i don't quite remember what the RPM's are at, i'd have to go check tonight. But it's just at those two speeds. any higher or lower and it goes away. The steering wheel vibrates and the truck just sounds a little different.

No, the truck isn't trying to shift. It's more like when the tourque clutch converter kicks in for cruising speeds, but even after it does, the noise is still present, but only at those two speeds.

engineman85 · February 8, 2008

i was having a similar problem and i replace the u joints and i still had vibration. then i broke down and took it to a shop and they pulled the drive shaft and had it ballanced now the vibration is gone. it was only off a little and it only cost me around $180 for the whole thing. i would only reccomend drive shaft ballance as a last check though, it is rare for them to come out of balance but it does happen.