i have a 1995 510 302...aode. an it won't shiftttt.

my abs an parking brake lights are on ... fluids are fine? not really sure if they're the same issue or not.

 

The RABS (abs) are tied into the odometer which controls shifting (partially) so it could well be related; most likely is.

 

Don't know if it would cause a shift issue or not but when I bought my 92 a few years ago the ABS and brake light were on almost constantly.
Turns out there was no oil in the differential. Filled it and it got better, drained and refilled again when I replaced the rusted leaking cover and it hasn't come on since.
I also pulled and cleaned the metal filings off the sensor each time, it is a magnetic sensor.
Good luck!