[Supras] Vibration Solved?

[Bob]

I put the car up on jack stands and started it up.  The vibration was
uncomfortable at 30 mph and it felt dangerous to be up on jack stands at 40
mph.

Pulling the rear tires off changed the vibration but it was still there.  I
was surprised how much noise was coming from the rear end of the car.

I supported the car by the rockers and I let the car idle in 5th gear.

This allowed the rear axle shafts to hang down and put on pretty much as
much strain on the joint that they ever have.  The shafts didn't click or
make any noise that would make me believe they were part of the problem.

There is a little play in one of the rear axle bearings but it is so minor
and it doesn't make any noise that I have pretty much ruled that one out.

I removed the rear half of the new OEM drive shaft that I replaced last time
I went looking for this problem.  This ruled out the engine and transmission
because in 5th gear and running almost 5000 rpms the engine and transmission
was almost perfectly smooth.

This leaves the center section.  None of the flanges, input or output has
any noticeable side to side play in them.  I can feel quite a bit of back
and forth play in the ring and pinion as I turn the input.

I have come to the conclusion that something has been failing in the rear
end for some time and what ever it is has finally gotten bad enough that I
can draw a conclusion.

Now I have to decide if I should repair or replace the carrier section.  I
have no idea what is wrong with it.  There is a lot of noise coming from it
and it appears that the assembly has been seeping fluid for some time.  I
never thought it ran low on lube but it is a possibility

I have been looking on the web and I can't find any listing of the ratios
available.  I know that it is not a locking unit but I haven't checked the
ratio that came with an 89 5 speed NA.

If I have to replace the unit I really don't care what ratio I get or if is
a locking or not.  All I care is that the speedometer can be made to work
properly.

Anyone with a good unit or a suggestion as to how to fix this one would be
appreciated

Bob