Re: Dreaded Tunnel Thump

[jack@domain.elided (Jack Hagerty)]

>From: Joel Hailey <alfadoc@domain.elided>

>In my experience, the most common cause for the dreaded driveshaft
>thump is tired rear springs. When the springs are partially collapsed,
>the driveshaft is working at an angle, with the bend in the middle, at
>the first U-joint, just behind the center support. The torque reaction
>on takeoff causes the driveshaft to want to push up where the bend is,
>hence the "thump". Replace those springs, preferably with something that
>makes the car handle a little bit better at the same time.

This is the only reply to this thread that makes any sense to me. So far we 
have had the usual parade of "informed opinion" including worn U-joints,
worn front donut, worn center support, worn rear motor mount and a too-long 
driveshaft(!?). The problem is that it started happening to my car after
*replacing* most of those components, and I can assure you that the
driveshaft is still original.

The rear springs are original, too, and the car has a noticable sag to
the driver's side. If this is truly a possible cause of the problem, then
it's a good enough reason to start saving for new springs.

- - Jack


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| Jack Hagerty                |                                             |
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