Dilema with 89 4cyl PU Truck Auto Tranny Won't Shift

I'm having a problem with my current favorite beater truck.

At speeds over 30 it refuses to shift into a higher gear. In fact, I can't
tell whether or not it is even shifting from first to second.

It is clearly in far too low a gear by the time I get to 40 (straining and
whining).

The OD button on the shifter seems to work as does the OD light on the dash.
Not that it's a definitive clue.

I recently changed the tranny fluid and filter, No help.

The only thing that's amiss is that I notice a fair amount of thick, gunky
oil on the lower part of the motor/transaxle. The vehicle is never down any
oil and this stuff seems too thick to be motor oil or tranny fluid so I have
to guess that it's coming from somewhere else. It looks like the gearlube
that we used to use in the differential of a RWD car.

Any advice would be greatly appreciated .

I've been trying to diagnose a similar situation on my 86 22R PU. At least
your switch and OD light works. Next step is to check the OD relay under
the dash and OD solenoid on the driver side of the transmission. The cost
of a new OD solenoid is $211 from the dealer, there is a way to always have
it on OD (on). Thanks to Marsh Monster, unbolt the OD solenoid and remove
the small O-Ring, and replace the Solenoid without the small O-ring. You
should have your OD back. If you know for sure the OD solenoid is working,
and still having problems, you might need to have the valve body serviced.
You should be able to get into 3rd gear, with or without OD.

Good Luck!

"Franknphilly" <francisi1@verizon.net> wrote in message
news:Vhxkg.9$nS5.7@trnddc07...[color=blue]
> I'm having a problem with my current favorite beater truck.
>
> At speeds over 30 it refuses to shift into a higher gear. In fact, I can't
> tell whether or not it is even shifting from first to second.
>
> It is clearly in far too low a gear by the time I get to 40 (straining and
> whining).
>
> The OD button on the shifter seems to work as does the OD light on the
> dash. Not that it's a definitive clue.
>
> I recently changed the tranny fluid and filter, No help.
>
> The only thing that's amiss is that I notice a fair amount of thick, gunky
> oil on the lower part of the motor/transaxle. The vehicle is never down
> any oil and this stuff seems too thick to be motor oil or tranny fluid so
> I have to guess that it's coming from somewhere else. It looks like the
> gearlube that we used to use in the differential of a RWD car.
>
> Any advice would be greatly appreciated .
>[/color]