Auto wont shift up, exp & solutions pls
 

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 :)

it CAN be caused by a bad TPS but what your describing sounds more like a bad tranny controller or solenoid pack. Occasionally the shift linkage can be at fault. Most likely an electrical issue if it did work previously and it hadn't been getting abused before it broke.

Thanks Big Evil, I will investigate, what's a TPS, where is the Tranny controller or solenoid pack, I hope it's an electrical prob, that's something I should be able to fix (I'm an electronics tech) hardest part is getting my head around how the BMW works. The only abuse it got the afternoon a few hours before it first played up was stop start traffic for a couple of hours heading north out of Brisbane after purchase- the idle was set too high & the auto got extremely hot, (I could feel it through the stick) but it didn't play up until a few hours later that night, came good then did it again in the morning.
Difficult to diagnose, I have a manual on CD but it's useless.

TPS = Throttle position sensor. The computers use its signal along with others to determine things like shift points etc. You say the idle was high and it got so hot you could feel it through the shift linkage? That can be one of those catastrophic overheat kind of events that'll kill the engine dead, you have to watch the temp gauge like a hawk and if it gets over about the 3/4 mark pull over and shut it down, if you see red your engine could be dead. If its overheating in stop and go traffic check your fan relay and electric fan, you may need to run a manual bypass to turn it on when in that kind of traffic if it isn't working automatically (could be caused by a bad thermistor in the a temp sensor). The tranny computer location, consult a manual. The solenoid pack is in the tranny. You're going to need someone with a scan tool to check it out first, which means a trip to to a shop that specializes in older beemers. Its the only way to be sure

Cable from the auto?
 

Thanks Big Evil,:worship
I checked the TPS it seems to have some effect so It may not be the problem. Investigating this area - intake to the carby at least fixed the rough idle, did a lot of cleaning & then made seals properly airtight that weren't between air filter & carby.
back underneath.
When I disconnect the cable that plugs into the auto I have 3rd gear, reverse & N. When the cable is plugged in I have 1st, reverse & N. This makes me think there is not much wrong with the auto, unless the fault lies in whatever the cable plugs into in the auto up the side, if so it's off to the auto mechanic & big bills I suppose. Otherwise where does the cable go? computer? under the seat or bonnet? Is there anything else I can check or change? I've tried to use my manuals on CD again but they are no use.
The shift linkage itself seems to work, otherwise I wouldn't be able to select R,D,N. Could a faulty E,S,M (econ,sport,man) switch cause this prob?
The engine didn't overheat before just the auto & the 2nd time was because the dodgy auto mechanic in Bundaberg unplugged the cable & said I could safely drive home in 3rd. That time it blew a ton of auto fluid out which gave me a trail of smoke off the exhaust, when I went back he plugged it back in, the auto then decided to work again (for over 1000 kms & a few weeks).:confused

Sounds like low fluid which can cause lack of shifting. Other things though, the cable being disconnected and it shifting indicates a controller getting a bad signal (or a bad controller). Yeah that could be an ESM switch, disconnect the switch with the tranny computer plugged in and see what happens. The controller is usually somewhere close to the tranny and the solenoid pack is in the tranny. If it was shifting before it could just be a signal issue. Other things include bad connector/s, or wires grounding or shorting out. Try the switch bit first and sourcing things from salvage yards aren't always a bad idea but you also don't always get good parts, so just keep that in mind. Nice work on the clearing up the idle.

....dear 1987 bmw with bad transmission...let me give you advise you may not like...when you are in a hole stop digging...cut your losses...after using bmw's over 30yrs i have sworn off...life too short to take on rebuilding old bomb....JimB

...scooter...saw picture you posted...looks like you have a great dog...problem is the car is also a dog...jb

Thanks jimjim, real constructive and supportive there.

These cars are warhorses, they don't die easily. MOST of the time they get scrapped because someone just doesn't take the time to figure out why something ceased working (after like 200 thousand miles).

Figure it out, fix it right, don't abuse it and it'll outlast dam near anything on the road by triple. When you've exhausted all the stuff you can check yourself, seek help and if it's dead, THEN decide what to do. New motor, trans and wiring harness along with interior and paint? Sure it'll cost as much as a cheap new car, but if it goes another 200,000+ miles, are you REALLY better off with the cheap and cheerful option? These are questions you'll need to answer for yourself when the time does inevitably come (and it will), but until your at the bridge, there's no sense in trying to figure out if now is the time to cross it.

I've run 5 old beemers 4 of them well over 200,000 (2 closer to 300,000) and I still have 3 of them. One has finally been retired to be rebuilt as a track car, the camo one is fully functional and used for promotional functions. #3 is an E34 with 180,000 on the clock and EVERYTHING works on it like the day it rolled off the showroom floor (daily driver). I've seen it with these cars repeatedly so I know mine aren't flukes.

Take the time, be smart about it. Don't listen to the negativity.

to rebuild or to junk
 

....you may have the rare ability, patience and resources to rebuild a tired, broke BMW. You are 1 in a 100. My advice to trash an old bomb was addressed to a seeming average new owner. My experience with the newer product tells me BMW is in trouble and the old quality is not there. I recently talked to an experienced pilot who knows cockpits, in his opinion the BMW cockpit is atrocious design, confusing, unfriendly and dangerous. My 2008, 535 was all those things. To each your own...

new models can't hold candle to older ones
 

...the new models are ungodly complicated and quality just not there, you become a slave to dishonest dealers who want to separate you from your cash...

Dude you are ON A SITE FILLED with guys who love and rebuild old BMW's. Yes the new ones ARE extremely complicated 79 computers on the F01/02 7 series. By the way I fix those too. I prefer the old stuff as do most people because they are more intuitive and have all the right stuff. New ones.....well thank American designer Chris Bangle (Mr. Pontiac Aztec himself) who thankfully got his ass disappeared back in January for that. You don't like Beemers and have an axe to grind......fine. Take it somewhere else. The guy whose car you're bagging on is reaching out for help because he's a do it yourselfer. There's a few things you can do to determine what the problem is and if it's going to be a cheap and or doable thing. Your position seems to be, its old, not perfect, trash it and buy something new without even at least finding out why......oh, and kick him while he's down 'cause that'll help. Did it ever occur to you that he might not be in a position to go out and swap his 2008 E60 for a 2009 Lexus? I'm suspecting your the kind of guy who couldn't tell me a dam thing about what's under the hood of your car other than what you read in the sales brochure. Enjoying that torque steer much? Or did I just fire one right over your head? You've gone from trashing a dudes classic to applying OTHER peoples bitching about NEW BMW's. You think it's dumb for a new owner to try and fix a classic car? I think it's dumb to not try and find out what's wrong and if you can fix it. You never know, the guy might end up being dam good at it but would have never found that out if he followed your advice. He may end up terrible at it but no one ever know that if they didn't at least try. As far as being a slave to dishonest dealers trying to separate you from your cash? All I can say is a fool and his money are soon parted. What did you do? Somehow manage to void the best warranty in the industry? Big baller rims and a boom boom stereo with all kinds of boy toy race crap? Go waste someone Else's time with your car that handles like a bucket of warm wall paper paste.

To Mr Evil The BMW Mavin
 

...I'm sure you can break down and rebuild all your classic BMW's in the dark blindfolded...address 2 issues without all the BS...what about the hundreds of thousands of BMW owners who have cars with factory defective transmissions. The only tranny i have ever blow up was last year a 525 with 60,000 miles. Question 2, what about the I-drive you love that also. I know nothing about that crap but hated it after 5 minutes in our former 2008-535...the only honest answer is never to buy another BMW...

you somehow feel that spewing venom on a BMW forum is going to somehow alter the fact that YOU failed to read and understand a contract PRIOR to you signing on the dotted line???
this forum and this thread are meant to help members with a specific issue so either contribute in a meaningful way or move along, thread jacking will not be tolerated.
we have specific sections for you to complain and this isn't one of them.

I've got the exact same car e32/m-30 . your cars shift mode switch should be auto and manual only with sport mode coming on when hand shifted into #3 position. your switch is from a 750 iL (zf 4 speed auto)and is not compatable with the 735 i's wiring(zf 5 speed auto) . get the right selector switch then go after the tranny computor, if you need to. I own both a 735 and a 750 and thought it would be cool to swap the switches and well I learned the hardway(didn't work it stayed in E). my 735 just passed 225,000 miles and will still stomp a mustang so dont give up the trans should go to 300,000 with out getting cooked in the mean time(abuse , overheating ect.) but the trans controllers do get funny sometimes and need to be replace. check your trans #'s with a dealer to confirm weather it's a 4 or a 5 speed. good luck