Posted by MoparNorm on Monday, October 18, 2004 at 11:38AM :
In Reply to: Shudder posted by Brett in AK on Monday, October 18, 2004 at 10:16AM :
...there wasn't really a lot of information about what type of vehicle, etc. but if it is a 4WD, W type Power Wagon, a common problem was with 'phasing' of the divorced drive line with the rear drive line. While this "phasing" borders on the 'prop-wash', 'muffler bearing' or 'track tension' gags of past generations, I have actually phased my drive lines and the shudder went away. Simply place the truck in neutral in BOTH the transmission and transfer case (BLOCK the WHEELS!) and rotate the intermediate (divorced) drive line to align the yokes on the rear drive line. It seems simple but it works to reduce or eliminate that shatter.
(Note: once you use your transfer case in 4 WD again, the alignment will have to be re-set after shifting back into 2WD.)
In line with Brett's suggestion, check the bell housing for oil leaks, your rear main seal may be failing and allowing oil onto the clutch/flywheel surface.
MN