My truck is experiencing vibration when at highway speeds of 70 and greater. Could the manual transmission cross brace mount rubber cause this? I have pushed on the tranny tail shaft and it appears "squishy" (A technical term). Other topics that come to mind are shocks, tire balance, and drive shaft carrier bearing. I have no clunking going from reverse to forward so I don's think U-Joints are the problem.

At 110K miles I am due for shocks and possibly the tranny mount.

Thoughts?

 

I would seriously look at ujoints, especially the fronts. My vibration started at about 65mph as well. Ujoints and alls well.

good luck.

 

If it shakes your belly or the hood vibrates it is tires, wheels, radial runout, balance, force varation, or loose suspension. Drive shaft will be faster.

 

u joints, all of them, start back to front and rest easy for another 100k,

 

Its not the tranny mount, definately a suspension or steering issue.

 

If there is ANY trace of rust at any bearing cap on the U joints then it will fail soon and that could be your problem. Might as well change all on the drive shaft you pull out as they are cheap. Just don't forget the mark each section of the shaft so it stays in sync when you re-assemble it.

 

Again with u-joints.. I just had a ton of shaking vibe on my Jeep that I could not track down by shaking/wiggling/pulling/twisting the-u joints. I decided to pull them anyway and they all had sticky grease and what looked like good needle bearings. Almost all of the bad vibes are gone now except for some lopiness that I think are coming from my tires and filthy rims....