That means if it does it in neutral, it ain't the driveshaft, Mars.

 

Don't be using 8 cylinder words like "reiterating". Whazzup reads this forum, ya know.

 

Jason you may want to replace your Ujoints like I am doing. I took the car over to Daytona yesterday for the supercross and noticed that at like 80+ I have a "harmonic" type of vibration. I am checking my U's today, mine is something in the drive train for sure.

 

Motor does not shake wildly when starting. I've seen the motor mount and it's okay no cracks and not crushed.

I have noticed though it's worse in 4th gear at 4k rpm, the other gears have very little vibration but in 4th gear it's wicked nasty.

 

No it does not do while in neutral

 

then are you saying the vibration is RPM related rather than a speed related?

 

Is there something in the t-5 that could start to come lose and feel this way? Anybody know?
Could a high mileage 8.8 make a vibration like a U joint going bad?

 

Bent drive shaft vibration gets worse as speed increases. Dose it do it as you slow down? Like if you are at 5 grand and let off the gas can you feel it when is passes the 4 grand range?

 

driveshaft possibly has a dent in it, if it was bent at 4k in 4th it would cause the u-joints to come apart,