The 89 740 did not come with a ZF tranny, it came with a AW 70L tranny ( L means full lock up ). i wouldnt worrie, i unbfortunatly has a failure in my AW which required a rebuild, off the top of my head i cant remember the actual part that failed, to buy the part was more then the tranny itself rebuilt go figure. all is well though, the AW series i know for a fact will run without fluid ( im married ) for quite some time. very very well built tranny, i rebuilt mine in my garage, there that good of a tranny. some of the tranny have a hard shift between 1st and 2nd, this ir normall wear and tear and isnt mission critical, if it doesnt bother you drive it like that no damage will be done being its in the vavle body ( 90% of the time it is too ).

Good luck