Wobble at 65mph?
 

My '73 has been wobbling in the back somewhere since I got it last month. 55mph is nice and smooth, 65mph sounds like I'm driving on one of those stips on the highway that are supposed to wake you up. Once I'm up to about 70mph it's gone again, all the way up to at least 100. (damn, I'm impressed my truck made it to 100! :lol: ) It doesn't have anything to do with engine RPMs, only speed.

Anyway, I thought my 33" tires probably need to be balanced. And the tread keeps picking up peices of gravel. Today I noticed that at 65mph the shifter handle on the t-case wobbles in tune with the rest of the truck. This makes me think maybe it's not the tires? Anyone have any thoughts? Could it be my drive shaft? For some reason the rear shaft is bigger than any other I've seen, like 6-8" in diameter. What's with that?

Re: Wobble at 65mph?
 

im going to bet its the driveshaft ... especially if its one of those two piece jobs with the carrier bearing.... those carriers will do wierd stuff like that

Re: Wobble at 65mph?
 

I agree, my dad's 87 Suburban was doing the same thing. The bearing was shot. Might want to check that out.

Re: Wobble at 65mph?
 

My truck only has the 1 peice drive shaft.

Re: Wobble at 65mph?
 

if it was worn u-joints on the drive shaft, you'd definitely hear it. Since there is no noise, I'm guessing tire/rim issues.

Re: Wobble at 65mph?
 

May be a balance issue with one of the tires.

Re: Wobble at 65mph?
 

Vibrations that occur at around 45-55 MPH are almost always tire related. You probably have a tire that is out-of-round or possibly a bent wheel?
Your "65" if un-corrected for the tire diameter is going to put you down closer to that speed range....

Re: Wobble at 65mph?
 

Actually, the speedo is dead on compared to my GPS.

I guess it wouldn't hurt to have the tires balanced though....