4x4 Vibrations and exhaust location?

[bmp34]

When i put my truck in 4x4 it starts vibrating at around 40mph really bad, i expect some vibrations from an older 4x4 but i figured i should be able to do atleast 55mph. I have 187k on the truck and let me know what you guys think i should do? I also plan on doin my own 4in exhaust and dumping in right in front of the rear passenger tire, im putting the bend right where the frame curves up, do you think i will have a problem with tire temperature? Let me know what you guys think. Also i am putting a 2-3in levelin kit on, how much will this kill my ride quality? Thanks in advance

[RoverIIa]

9 times out of 10 you have a bad u-joint in the front driveline.

Take the driveshaft out, put it in 4x4, and run it for a while. No vibration means it is the driveshaft.

Still vibrating... look to the front axle for a problem. I think you can probably use a vacuum pump to engage the front axle while you are still in 2wd, unless you have locking hubs, then just lock-em in. This will let you diagnose a front axle versus transfer-case problem.

It is probably one of your CV joints, usually the one in the driveshaft.

You don't say what year your truck is... that info is necessary to make educated guesses about these things.

Good Luck.

Nate

As for exhaust, a temperature problem is less likely than hitting your exhaust if you cycle the suspension all the way. Remember that the axle moves more than just what you can do with a jack. If you only ever drive on the road, and don't let the truck sit and idle for hours, you are probably okay.