Bad Vibration on Deceleration

[dw driver]

The driver is telling me that our car has a pretty bad vibration when letting off the gas for a caution or at the flag. The car is a 6 year old Shaw that seems to be working pretty good, other than that. We've replaced the top shock, replaced the pull bar bushings, have the pinion angle at only 6 1/2 degrees. The u joints seem to be fine, so we didn't replace them. Any suggestions on this would be greatly appreciated.

[Mad Jack]

Possible Drive Shaft, Or Transmission Output Shaft?

[riddle28]

sounds internal trans to me. maybe the front cage bearing on the output shaft

[JustAddDirt]

If it is a standard slip yoke transmission. You may try putting a new bushing and seal in it. Also how much yoke is in the transmission?

[Lizardracing]

Drive yoke, driveshaft joints, pinion bearings is what I would start with.

[JustAddDirt]

what about tightening up deceleration bushing on pullbar, or replacing it with a harder one?

[dw driver]

Thanks for all of your replies to this. Well, we changed both u-joints in the driveshaft, put a new bushing in the Brinn tranny, and still had the problem. We then changed the complete driveshaft and the problem went away. Again, thanks for the help.