1988 C2500 2 wheel drive - drive shaft question

[mountie]

"Axles & Brakes" is the closest I could find, to ask about my driveshaft.

I finally drove on the Florida freeway ( very smooth surface)... after some good work under my truck.

New Michelin 'Defender' tires, new steering / suspension ( Moog), transmission mount, new U-joints, new harmonic balancer.

When I get up to 65 mph, I start to get a light vibration/ humming, coming from the back half (?) of the truck. I feel it in my seat, ..NOT in the steering wheel.

( Just a thought).... could my driveshaft had lost a weight, causing the vibration?

( My original driveshaft is aluminum ends & a carbon fiber shaft )...

UPDATE; I failed to mention.... My motor mounts are bad..... could that be a cause of an even-feeling vibration while driving above 65mph? ( I hear the shop labor is about 4 hours to replace!!) ouch...

Any thoughts???

 

[evilunclegrimace]

You have to fix what you know is in need of repair before you start looking for other problems.

 

[mountie]

You have to fix what you know is in need of repair before you start looking for other problems.

I totally agree... motor mounts are next..... ( I was not clear if bad motor mounts cause vibrations)

I know a motor will "clunk" when a sudden load is put on engine... but mine doesn't clunk.