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'93 940 na, 207k miles. Maintenance is up to date, and there is still a lot of car left in this one, but...I'm running out of ideas and thought I ask The Board.
After replacing the transmission mount, it developed a serious seemingly-exhaust-related vibration - most evident from about 2700 rpm's to 3000 or so. The vibration (and roaring noise that accompany them) vary with engine speed, not vehicle speed. Can be reproduced in the driveway in park or neutral - most evident when you let off the gas after revving to 3000 rpm. When driving, there is more trannie noise (whirring) backing out of the driveway, or moving away slowly in drive. The sound just feels like a part of the engine is contacting the body, and transmitting every sound into the cab. Listening to the car as my wife drives it away - seems completely normal. Seems to run fine...
However, under load at 2700-3000 rpm, it roars in the car and vibrates in the car something fierce. This is not the ride of a semi-luxurious Volvo, I'll say that!!
Here's what I've replaced with Volvo OEM parts:
trannie mount
AW71 rear output bearing and seal and bearing case (had spun the old bearing)
"intermediate shaft" connecting shifter in car to shifter lever on AW71
motor mounts - engine sits 1/2 inch above cross member
harmonic balancer pulley - old one was off balance and causing belts to vibrate
exhaust manifold to down pipe gasket - although I'm having a hard time getting a good seal.
two new exhaust hangers (rubber parts)
I've inspected the entire engine and trannie and not found any contact with the body. I've loosened and retighted the exhaust joints on the chance that the pipes are causing binding somehow.
The driveshaft, u-joints, center bearing all seem fine. They have maybe 30k on them, but I can find no evidence of slop (and I can produce the symptoms in the driveway without the driveshaft even spinning).
Ideas, places to look further greatly appreciated.
(Bruce Young - did you ever solve your car's vibration problems???)
Thanks in advance.
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