Driveshaft balance issue / Drone

[Corvette1974]

Hello. My M1028 is on the road and better than it has ever been, except one thing. There is a drone and vibration that starts at about 35-40 MPH, and partially receeds at 47 MPH. I think this is the driveshaft, as there is a 1/4 inch deep (about) dent in it right in the middle. When you let off the throttle from a high speed, it also drones and vibrates.

Would this be the driveshaft, because of balance/dent issues?

Also, this is not directly related, but the front driveshaft doesnt have any grease fittings on it, when the TM says it should.... Whats the deal here? The truck is a completely original untouched 1986 M1028.

Will

 

[rbeasley66]

Sounds like a new rear drive shaft might be in the works.

My front drive shaft doesn't have a grease fitting either. It had a fiber, wire wrapped cover over the slip joint, which I damaged while stuck in the Florida mud. I'm looking to drill and tap to install a grease fitting and make a rubber hose to cover the slip joint. What I discovered when I put a 2" lift on it was the front slip joint was frozen solid, don't know how out didn't tear something up that way. It took a lot of hammering and pulling to get it apart, and a lot of cleaning to get it slipping again. A well used grease fitting would have prevented that problem.

 

[Corvette1974]

Sounds like a new rear drive shaft might be in the works.

My front drive shaft doesn't have a grease fitting either. It had a fiber, wire wrapped cover over the slip joint, which I damaged while stuck in the Florida mud. I'm looking to drill and tap to install a grease fitting and make a rubber hose to cover the slip joint. What I discovered when I put a 2" lift on it was the front slip joint was frozen solid, don't know how out didn't tear something up that way. It took a lot of hammering and pulling to get it apart, and a lot of cleaning to get it slipping again. A well used grease fitting would have prevented that problem.

Haha Alright, I just wanted it make sure that that is what it is, I'm gonna get my current drive shaft rebalanced and have the dent removed, along with new serviceable U Joints installed.

Yeah my front shaft has a metal clip held in rubber boot over the slip joint. Maybe I'll look into doing something with some grease fittings in it. I have to do the front and rear output seals in the transfer case anyway, I'll do all of these things at once.

Will

 

[timarr]

Will, Kublos surplus which is in north east PA. Had nos driveshafts with joints for 100.00 at sussex swap meet. Call them I remember about 10 of them at the meet.

Tim

 

[319]

Will, Kublos surplus which is in north east PA. Had nos driveshafts with joints for 100.00 at sussex swap meet. Call them I remember about 10 of them at the meet.

Tim

Be cautious, the M1028A1 and M1008 shafts are not the same length.

 

[ODdave]

Be cautious, the M1028 and M1008 shafts are not the same length.

? 1031 would be differnt why 08 & 28?

 

[319]

? 1031 would be differnt why 08 & 28?

Crap!

Meant and was thinking the M1028A1

 

[Corvette1974]

Alright, I'm just going to have the driveshaft repaired and rebalanced with new U joints. I'll let you guys know how it comes out.

One more thing- I need to change the front and rear output seals in the transfer case. Does this just involve removing the yokes, and seals and installing new ones? Should I RTV the splines and what is the torque for them?

Also the Differential input seal needs replacement- Same thing RTV? Torque? Do I just mark it and retorque to that mark because of the pinion adjustment?

Will