My BMW 735iL 1987 with ZF auto box won't change up from first gear.
It happened on the trip home about 300 kms after I bought it. I was stranded, a busy auto place disconnected the computer plug so I could carefully drive home in 3rd gear, it overheated after 10kms, I returned he refitted the plug & it worked fine for a few weeks. The problem returned, the switch E,S,M seems to work although manual selection doesnt seem to do anything.
I have emptied ATF removed auto pan cleaned filter & magnets. I didn't realise I needed more than 4 ltrs fluid so put 4lts of new fluid back in & 3 ltrs of used (but filterd) fluid back in. Still has same problem, can rev out to 7K RPM in 1st no change, reverse is fine, selection of R N D is fine rocking shift between 1,2,3,D does nothing. Low revs is also a rough. This is a very nice looking, well looked after old BMW that I obviously got cheap
Is there something more I can do myself? I'm pretty handy DIY obviously