real bad vibration

whiplash11 · February 14, 2003

i just got a 10 inch whiplash susp. lift installed on my 2003 chevy 1/2 ton reg. cab with 35x15.50 tsl-sx and 16.5x12 welds. i get a massive vibration ing the front end, and also possibly in the rear,right aroung 40mph and again at 55. i have yet to install a steering stabilizer, could that be the problem, or maybe the tires, any info or suggestions would help

Sierra5.3 · February 15, 2003

What kind of tires are your running? If they are pretty aggresive then you could expect vibration.

whiplash11 · February 17, 2003

this vibration is god awful (you get out of the truck with a headache)and ive narrowed it down to a vibration in the rear of the truck....

Sierra5.3 · February 17, 2003

Those tires that you have on right now are pretty aggresive, so I would rule that for the vibration. without a doubt. Plus when you lift your trucks everything is more heavy-duty like the leaf-springs and shocks, so that might also be a factor. Otherwise I dont have a clue.

cyrylyn · February 17, 2003

10 inch suspension? that might have something to do with it.. who makes the shocks? are they adjustable? what is your tires' PSI?

redz 4x · February 19, 2003

1/2 ton regular cab, prob with a 6.5' box?

Time to check the driveshaft angles!

I think the extended cabs can get away with more due to the longer wheelbase. 10" is a LOT of suspension lift on a short wheelbase standard cab truck-old or new. Call Whiplash and ask them. Make sure if they used rear lift blocks, they are installed correctly (tapers down towards front of truck), or if there are springs, the shims should also taper down towards the front of the truck. Either of these will reduce pinion angles.

I suspect vibration due to extreme driveshaft angles.

redz 4x · February 19, 2003

Ya, tires are going to effect the ride, as will shocks, but as to the vibration you are speaking of, my above recommendation seems to jive with what you are describing. I had a blazer with a bad rear driveshaft angle and the vibration was unbearable!!! It was easy to diagnose for me- see below.

Laymans vibration test-

When vibration was at its worse while driving, I let off of the gas for a few secs. The vibration became much less severe. So, I was able to assume, that since the vibration was much more severe under load, the problem was the drivetrain. I put in a 6 degree pinion shim, and the vibration went right away.

If the vibration is constant, maybe get the tires rebalanced, check the alignment, shock valving, etc.

good luck