So I recently bought this used transmission to go with the motor I got, It looks as though the guy had it sitting outside for a while. Today I pulled the top off the transmission tail shaft and was greeted with a pretty scary sight. I was able to clean the top off pretty well(you can see it in the corner of the pic it was just as bad as inside before). What do you all think I should do about this? Im assuming I cannot use any rust neutralizing chemicals inside of this area without disassembling first? My main concern is whether this section leads into the transmission itself? For example on my corolla transmission I can use the shifter hole to actually fill the transmission with fluid. If this transmission is the same way, I am concerned of what may have made its way into the transmission itself, which would also make me weary of using any kind of chemical(s) to remove the rust. What do you all think I should do about this? Im assuming that the only option I have here is to disassemble the tail half of the transmission clean up everything individually and hope it hasn't rusted/gunked up too much inside? any help or input appreciated

 

Some early trannies were susceptible to water leakage in that area , there was a TSB about the issue.

I would treat and clean the area with the rear of the tranny sitting upwards and tilted, there is a low chance of fluid or rust making it's way into the main body of the tranny but you don't want it to get into the shifter rod either. Grind the rust ground down, then have it treated, and then coated to prevent further rust from forming, rustproof and grease the parts.

 

I can almost guarantee that none of the water made it's way into the trans. Water might go to the front of tube, where it will meet the shift-shaft seal. There is nothing sealing the rear end of the tube.

There is no pathway/connection at all from the shifter well to the transmission main case, only at the front end of the tube.

Pulling tailshaft is easy, do not remove the output flange or large center nut, it will all come off with the tail housing.

Pull that rusted part off (just remove 12mm head bolt), and the tail housing, and check the shift-shaft is not rusted on the front end where it rides on the seal.

Being that the trans is currently in 4th gear (shift-shaft forward) there is a very good chance that the shift rod was protected. If it was in third, the rusted portion could be pushed into the seal.

 

Thank you both for all of your help. I will get right on it!