A curious vibration in my RTS

[HighTechRedneck]

My RTS has got a strong vibration that is felt throughout the coach. It only occurs while passing through 50-53 mph range either accelerating and decelerating.  In other words, when accelerating it starts when I hit 50 mph and stops by 54 mph and when decelerating it starts at 53 and goes away at 49 mph.

As additional info, it is a 82 RTS II with 6V92T/730.  The 2nd to 3rd shift point is 25-30mph under normal conditions.  The maximum limit of 2nd is 45mph.

I have read that it is a common problem for 2nd gear to drag a little in the 730.  Would this cause this type of symptom?  If not, any ideas?

[Chris 85 RTS]

Have you joined the RTS group?  Lot's of info and knowledgable folks there.

http://autos.groups.yahoo.com/group/RTS-bus-nuts/

[Hartley]

My RTS did that once. Turned out to be a tire problem on an inside dual that was out of round and underinflated due to
a leak. Actually broke the bead loose and the tire flopped around on the rim only at certain speeds.

The only other thing to check is the transmission modulator, It may have a weak spring or leak in the air line that could
cause the transmission to start hunting gears or lock-unlock the torque converter.

Do you still have the a/c compressor on top of the transmission that runs off the PTO pulley. I had a FLX that had a
bad PTO that rattled at certain engine speeds. It finally stopped turning when the gear cluster driving it failed and it stopped making noise too...

[Sammy]

Check the driveshaft u-joints and the output flange and retaining nut on the trans too.
Take a look at the bolts that hold the d-shaft flange to the trans output flange.