My guess is the transmission...mainshaft bearing.
steve

John Mates wrote:

> Dear List Members:
>
> My patient is an '86 Syncro Weekender.  Symptoms:  bad vibrations
>
>         1) Strong vibration at middle RPMs at 50 mph.
>            The car shakes so badly that I think that
>            ancillary problems may occur.
>
>         2) The vibration happens ONLY under load, but
>            it seems especially strong under a light load.
>            Otherwise the car drives as smoothly as silk.
>
>         3) With the hatch up, I have noticed that the
>            engine vibrates strongly when accelerated
>            into the middle RPM range by hand (sitting
>            in the garage in neurtral.)
>
> My fixit efforts:
>
>         1) New tires all round. Rotate wheels.  No effect.
>            (Rear tires were badly worn.)
>
>         2) New rear wheel bearings, and brakes.  All new
>            rear CV joints. (One rear bearing was worn out
>            and one rear brake tended to lock on.)  No
>            change, but better brakes.
>
>         3) Replaced driveshaft with another used driveshaft.
>            No difference.
>
>         4) Replaced front diff with another used front diff.
>            No change.
>
>         5) Currently replacing engine mounts, guessing that
>            the old ones were worn out.
>
> If #5 (engine mounts) doesn't work my remaining guesses are:
>
>         1) Engine misses at certain RPMs and I need to have
>            the engine examined.  Could this shake the car?
>
>         2) Transmission.  Is this RPM dependant shaking under
>            load a common symptom of a bad transmission?
>
> Since the engine already seeps slightly at the heads, and since
> the remaining possible solutions I am looking at (engine, tranny)
> are very expensive, I'm feeling the need for advice ...
>
> I'd really appreciate comments.
>
> John
> jmates@ichips.intel.com
>
> --
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>
>  John Mates, Intel Corp.
>
>  JFT
>  5200 NE Elam Young Parkway
>  Hillsboro, OR 97124-6497
>
>  jmates@ichips.intel.com
>  (503) 264-8023
>  #include <std.disclaimer>