Tranny going dead, sell it ?!? part it ?!? All suggestions appreciated.

[amsmk]

I loved every minute of driving with my 89, 535i (174k) until recently the reverse started to act funny . I can drive it forward but almost every shift is with a kick, and the computer started warning about the transmission.
A local guy (BMW expert) can get me a tranny and install it for $1700.
I have three options:

Sell it as it is, (any ideas how much? the body and inside is very clean and the engine runs perfectly).

Part it out.

fix it and then sell it or perhaps keep it. (how much should I ask for it?)

I would be very appreciative to have your advice.