Ford Taurus Troubleshooting Question

1990 V6 3.0 liter engine 170 k miles on engine that runs excellent.
Traveling down the highway at 50 mph I hear a short whine from the
engine compartment and the speedometer needle goes haywire fluctuating
wildly back and forth. The car decelerates and I pull off the road.
Engine operates fine but won't move when put into gear. The shade tree
mechanic I had pull me in believes the differential pin is the problem
(didn't have him open things up because I don't want him to do the
job). Does this make sense? The transmission was replaced at 130 k.

Any opinions as to the possible problem and guestimates as to how
costly to fix would be most welcome. The age of the vehicle makes
major mechanic repairs economically unfeasible.

Thank you in advance for any light you can shed on this problem.

> Assuming your CV joints are intact (did you check them?)
> It smells like trannie. Unless you can get a used one cheap and
> put it in yourself, the car is junk. ITs probably 2K or so at
> a trannie shop. IN a 90, you have a AXOD. 91 or so up used
> AXODE and will not swap in (electrically shifted).
>
> I had a 90 with hydraulically shifted trannie and it was much smoother
> than my now laid up 93 wagon.
>
> Bob
++++++++++++++++++++++++++++++++++++++
Thank you for your response Bob. As a matter of fact I have noticed
a problem with the front end prior to this incident. When accelerating
up any incline the car experiences severe front axle rumbling and
vibration in the 35 - 50 mph range.

I assumed it was a cv joint going bad but didn't know that this
could be related to the problem described. Wouldn't both cv joints
have to be completely ruined to have this happen? What would I look
for under the front end? CV joints hanging down? Thanks again for your
input.