I just got this truck and it has had this really bad vibration in it going down the road. I thought it was tires out of balance and maybe a bent rim but all that and more has been replaced and the vib persist. here are some specs.

93 ext cab dakota w/318 4x4 auto trans

Replaced
Pitman arm
1 inner tie rod
Every U-joint it had.
complete rear brake rebuild, excluding drums.

I'v had 2 mechanics tell me the wheel bearings are fine. I dont know if maybe they have gone dry and that could be the cause of the vib?

I checked the rear end lube and it was low so I pulled the cover and the gears look fine to me.

I have jacked up the rear and taken the drive shaft out. put it in D and let her get up to about 50- 60 mph and there was no vibs. so I think Its in the drive shaft or the rear end. can anyone tell me if there is a bearing where the drive shaft slides into the transfer case that could have gone bad?

Im out of ideas the vibs start around 30 mph and come and go with the shifting of the transmission BUT its not in the Tranny. it smooths out around 55- 60. Also the vib is kinda "rotory in form" it comes and goes or fades in and out. but at the same time is almost constant.

any ideas would be a great help. thanks rad

 

https://dodgeforum.com/forum/1947777-post6.html

See if that helps you narrow it down... I'm at a loss for what advice to really give you at the moment

 

Thanks for the link. It was helpful in a way.
after reading it and studying the chart Im really hoping its not a bent axle.

Could someone tell me what CASTER ADJUSTMENT means? In reference to adjusting angles of the drive shaft u joints.

 

could be a bent or out of balance drive shaft....

 

I know this sounds stupid, but you could coast a hill or use a tow strap without your drive shaft and that would rule out the axle if the vibration did not occur. My vote is on the drive shaft not being balanced.

 

Sounds like the driveshaft to me. Check the u-joints in addition to balancing the driveshaft. I had my u-joints go out and the truck had a bad vibration before they went.

 

ok Ill try to find a driveline shop or someone that could look at the shaft for me.

I did notice that when going down hill, no matter if coasting braking or exel it vibs worse than going down a flat road. up hill is bad but not as bad as down hill.

siggie30 I like the idea with the tow strap, and will have to give it a shot. No other option i guess.

Thanks for the reply's. rad