I'm writing in on behalf of Dad. His '99 4x4 diesel has been giving him a bit of trouble lately. Coming from the front passenger side is a vibration @ ~ 55-65mph IIRC. As for the fixes tried, here we go...
- Balanced and rotated tires. They are A-OK. Vibration still occurs.
- Shop gave truck a front end alignment and front end check. Steering box, pitman arm, track bar, tie rods, joints, shocks, trailing arms etc all OK. The alignment was slightly off, but it was corrected. The front steering stabilizer was "weak to one side". Vibration, while slightly relieved, still occurs.
- New stabilizer purchased and installed. Vibration, a little more remedied/masked, but again, still occurs.
Dad and I are at a loss as to what could be the issue at that particular range. One up to speed 70-77mph, the vibration is not present. Next on the list to check is the axle shaft Ujoints. But from there, we don't know where else to look.
On another note, the truck doesn't seem to like this new diesel dad's been putting in it. Or at least, the truck has been acting up somewhere in the "it won't accelerate" department. RPMs jump when the accelerator is pushed at speed (like when overtaking on the highway), but the mph will not budge. However, this may be a tranny issue that is creeping up at a coincidental time.
Dad is thinking of buying a new truck with the new engine, but not until he's got the amount of money to put down that he prefers, and he also wanted to keep his '99 for the farm/pasture/fishing duties. So, "get a new truck" isn't the option we're seeking at this point