I'm six months into owning a 1998 XC-70 with 176,000km on it which manifests two similar driveline behaviours:
1) At a stop with foot on brake for more than a few minutes, I can almost always get a minor "bump", which feels as if someone has tapped me from behind with their front bumper..... no movement, no dip in the tach, and this has happened again in particularly long stops for gridlock. Has been doing this the whole time I've had it, and2) For the last several days, I've gotten quite a "thump" which seems to be from the drivetrain, but occurs while cruising between 80-100km/hr. No acceleration, no kick-down, just steady load/speed. The third time this happened, the driveline seemed to slip for a second, before catching back up... but I was unable to see any change in the tach or speed..... These episodes last only an instant, and give the impression I've run over something (but with only one wheel/thump). Tranny functions crisply through anything I throw at it otherwise. Other than startling me, there seems to be no other effect.
Tranny was flushed completely at 162,000km.
Dealer had car in shop and on the road today... no abnormal codes, performed flawlessly on the test-drive. Replaced the LF wheel-bearing, which was likely coincidental, and *did* note the lower engine mount to be separating (I think this an unlikely cause...).
Any ideas/experience from the cognoscenti ?
Merci,
Kevin