Did a search a did not really find anything specific to my issue. I have a 97 D1 with 158K miles on it. Recently I noticed that while driving on the highway above 50MPH and letting of the gas, I get a grumbling noise. Sounds almost like a motorcycle passing you. Sounds like it is coming from the front. Slight vibration as well, but cannot be felt in the steering wheel. Not sure how long it has been doing this, just noticed it the last couple of days. The truck has OME HD springs and shocks.

Any ideas, front driveshaft, could the rear rotoflex cause this??

Thanks

 

Looked at Front Drive Shaft and seems to be okay. Trying to remove it and having a hard time. Are they studs with nuts on the end? Once removed I can lock the CDL and see if the noise goes away.

 

Is the vibration in the steering wheel, your seat, where?
Does the noise change sound/pitch/location/volume when you change lanes or turn corners?

 

Same problem here on a D2 with 125k. I just noticed it recently. I think the wife noticed it some time ago, but it is her vehicle.

I replaced the front shaft last year with a top of the line Tom Woods, and recently had it lubed with no change in noise. (At least the shop said they lubed it.)

I was concerned about the rear rotoflex, but it seems pliable, and is not visibly deteriorating yet.

I will probably make sure all is lubed tomorrow and try again, since the dirt on the zerks looks old.

 

The vibration can be felt in the vehicle, not through the steering wheel. I think I have narrowed down to the front drive shaft. When driving slow today, you could hear it creaking as it rotated. Pretty sure that is where it is coming from. Having a hard time disconnecting it. Can't seem to get a 9/16 box wrench on the bolts securely. Afraid I might strip them. Let it sit most of the day with PB Blaster to help. Any suggestions on getting it off quicker?
Thanks

 

No, no tips for getting it off other than 2 box end wrenches.