Engine/Transmission (1994 - 1998) Vibration 70-80 mph

[stover]

Help! I've got this vibration that has me stumped and can't seem to track down. It seems to be the worse around 70-80 mph. It doesn't seem to be in the steering but I can feel it in the seat, the center console, floorboard, and the dash. I have even ran it up to speed and then kicked it out of gear and didn't seem to change anything.



Now for the things I've done to it to help track it down. I had new tires put on 245/75/16 and had them rebalanced 2-3 different times. The garage even sent 1 tire back thinking it might be bad but it didn't chance anything. Had new front ujoints and upper and lower ball joints put in. I have the 3rd generation track bar kit in so its not my trackbar. Just last week had my rear ujoint in the driveshaft replaced and also the 4x4 front driveshaft ujoint replaced. (The front one had some play) Took my driveshaft off and had it cut and welded and rebalanced. That changed the pitch of the vibration to a higher constant vibration. Talked to the shop about it so they took off the round donut vibration dampener thing and then rebalanced it again. That made the vibration not so severe but I definetly still have it. Taking that donut off definetly made more chatter in my gearbox which I don't like. I do not have a carrier bearing. My driveshaft is a one piece. Not exactly sure what to try next?





95 Dodge 4x4 5-speed 3gsk afe progaurd7 #6 plate kdp fixed 17 timing guages 4" straight pipe airbags mag-hytec rear cover

 

[K5IP]

Is this happening when only in 2wh drive? If so,

Sometimes a bent yoke at either end of the drive shaft will do this. Runout can be measured using a dial indicator at 180 deg spots on the either side of the yokes.

Rog

 

[TRAMPLINEMAN]

Did this start right after the new tires were installed? If so, I just had the same problem. Anywhere from 0-79mph was fine, 80 and above, bad vibration. Brought it back twice to rebalance the tires, no change. Took it to a different tire shop to have them rebalanced. All four tires were way off. No vibration at all now. Guy told me that some shops wait too long to get their machimes recalibrated so when they read zero, it isn't actually zero'd out.

 

[stover]

I think I'm gonna take it to another shop and get the tires rotated and rebalanced and see if it does anything different. While its on the lift I will have them check the pinion nut (dana 80) and the axle ubolts just to make sure everything is tight since I put airbags on.

I did a search on this and someone talked about having too much toe in. When I had the truck aligned I put about 800 pounds in the bed and then had them align it because over the summer I pull my 6500 lb bumper pull trailer alot and had noticed uneven front tire wear. I still have the 800lbs in my bed for plowing and maybe should take it out and see what happens.