[[ Taken from a post I sent to BJ Kroppe about fixing the
driveshaft rumbling in his 82 XJ-6 ]]
Date: Thu, 14 Dec 1995
From: Greg Meboe meboe@lestat.scs.wsu.edu
To: BJ Kroppe
Subject: propshaft rumble
BJ and others,
My propshaft "rumbling" occurred mostly in 1st gear, at any power
level above 1/2 throttle. If there were several people in the car, it
would commence rumbling at 1/4 throttle and above.
Sometimes I would get a rumble in 2nd gear, but only if the shift
occurred at relatively low speeds and only if I had my foot stuffed to the
floor. Sounds like a strange set of circumstances, but it would happen
say if I was accelerating slowly away from a light, and nailed the
throttle just when the developmentally-disabled GM-400 transmission
decided to slowly shift from 1st to 2nd.
I took the car to a transmission shop here in Bellevue which had
a good reputation for Jaguar repair. The owner said that he had seen
this many times before and the problem was a worn rear mount rubber spool
bushing. Hmmm I said. (I'd just finished changing the tranny and the
rubber bushing looked brand new). He said that he could replace the
bushing and spring spacers for around $100 and that might fix the problem.
Being a poor college student who has never paid anyone to turn a wrench,
and being not convinced that he knew the exact cause of the problem, I
thanked him and left.
Al Gerard Jr. at Gerard Coachworks said to check the driveshaft
alignment, and when I slid under the car I found that the 10mm bolts
holding the center carrier bearing (recently replaced before I purchased
the car) were not completely tight. Upon consultation of the factory and
Haynes workshop manuals, and after de-gritting all of the involved
components, I set the bearing about midway (transversely) in it's
mouning holes and tightened the bolts. The rumbling problem nearly
disappeared, and within two iterations of transverse bearing adjustment,
the last one having been secured with Loctite, I was on my way.
When I throw that GM-400 tranny away in favor of a BW T-5 manual, I'll be
sure to leave the 2-piece driveshaft connected to it, so that I replace
the thing with a 1-piece unit.
I hope this helps you,
Greg
Greg Meboe meboe@lestat.scs.wsu.edu
Web site>> http://www.scs.wsu.edu/~meboe
Dept. of Mechanical and Materials Engineering
Washington State University, Pullman, Wa.
'85 XJ-12 H.E. (daily) '67 Spit-6 '74 TR-6