no reverse manual transmission

[confusedbyitall]

Hi- I have a 1988 325 with the getrag 260 manual tranny that won't go into reverse. I have the tranny out of the car and it just won't go into reverse no matter how much I manipulate the shifter rod. It is not the external linkage as I have eliminated that. My question is "Is it worth tearing apart (seals, special tools, at a minimum) or should I just get a used unit?" Thanks for any help anyone can give.

[dandydog]

I replaced mine from a 'yard for $150 (I think) about 5 years ago, and have had no problems with the replacement. (Collateral benefit: If you decide to tear into yours, I've got a spare Getrag unit with 3rd gear problems you can use for parts.)
Neil