Trans issues?

[Notaweekend]

I have a 1987 535is with the automatic ZF trans that has the switch for sport, E, 3-2-1 I believe it’s called 4hp22-EH

For the last year I’ve had issues on and half. First noticed after sitting for a winter that the trans gear warning light was on, and driving like it was in limp mode. A few days later I start it up and drive it and it’s fine. Drove it that way for 6 months and only one night in the city I had some issues with the trans being clunky on shifts and not shifting up or down in time the way it should. Again the next day it was fine.

For the last 2 months I’ve had it sitting and just took it for a test drive today. Started out OK and after 45 minutes I had issues with clunkiness, not shifting into the next gear when it should be, not down shifting on time... eventually it would act like it’s in limp mode meaning feeling gutless taking off from a stop. If I shut it off and then right back on it would be fine for taking off from a stop, but then be right back to the clunkiness and gutlessness

Hope I’m explaining this clear enough

Does it sound like my trans is shot or maybe something else causing problems? TPS? TCM?
Note: before sitting the first time, before any initial signs of tiredness, I changed the fluid and drove it to California then back to seattle.

[Ju@n]

Try removing and cleaning the trans connector. If that doesn't work and you've already done a fluid/filter change then it CAN be more serious (although it can also be the TCU but never heard of them breaking)

[Hit Man X]

The gear with the 'A' symbol is limp mode...aka third gear (1:1) and reverse only, typically with max line pressure. This is due to a power supply problem to the transmission.

Clean the case connector with Deoxit. There is also a relay in your car, I cannot tell you where but on the E23s it is in the speaker covers in the front. The case connector can leak from its internal o-ring AND through the connector rubber itself. You must drop the valve body to service the o-ring and at that point you may as well have it serviced and the shift improvement spring installed while it is apart. If your rubber is leaking, you need to pop it apart. Shorten it and reseal with a high end sealant.

Relay is a relay, I would replace once you find the correct part. I recall on -059 cars I have torn apart, there is a small jumper connector with about 13 pins that powers the EH from the engine harness. I would consider unplugging it, Deoxit it, reinstall also.

ZFs are simple and durable when taken care of well. Most I have disassembled for rebuilds have clutches that could be reused easily. Yet, 40 years progress of friction material makes it silly to do so.

[catso]

These ZF trans respond well to synthetic fluid. Change it once or twice at least and of course check and verify the electrical connections.

[gadget73]

I have a non-EH version of this that had similar issues. Turned out to be crap in the governor. I drained and re-filled the pan without removing the pan to clean it and I think I stirred the junk up. The car sat for ~10 years too. Gov job wasn't any big deal, pull the driveshaft, remove the tailshaft housing, and there is a snap ring or something back there that holds it together. Forget the particulars other than it was not very hard to remove. Once I had it out I pulled the governor apart and flushed it out with brakleen. There are two plungers in there and a spring, not exactly a complicated item. Once the garbage was off the parts, the plungers moved correctly again and the trans shifts fine now. If you do this, you'll need the tailshaft gasket. I did drain the pan before removing the tail, not exactly sure if that is needed but I was planning to drop and clean the pan out anyway. Mine did have noticeable amounts of sludge in the bottom of the pan too.

just a thought in case its not anything to do with the electrics.

[Notaweekend]

only when it rains. literally. ONLY when it rains!

I JUST replaced my transmission with a rebuilt auto trans and drove it across the country without a single hiccup.

Now everytime it rains over night and I come out the next day to use my car the thing drives in limp mode. Park it in the sun for a day and next day its new!

what the hell. Can anyone offer any insight? what might be my problem? To reiterate: i just replaced the transmission. the fluid is full.... ???

[Mike W.]

Bad spark plug cables can be an issue when it rains and I've heard of O2 sensor problems, but not tranny.

I assume the limp home light is coming on? It seems unlikely to be a problem with the low voltages involved and weather, but I've heard of the connector plug to the tranny being cranky, you might check that. Is the rebuilt replacement still under warranty? I'd check with them. Even if it's not under warranty I'd talk to them and suggest it seems like the original problem was never fixed with the replacement. My guess from here is it's a wiring problem, not mechanical, not electronics, but the right signals aren't getting to the trans. Just a guess.

[Notaweekend]

maybe the selector switch went completely bad?
or
viewtopic.php?p=963021

saw this and it sort of sounds like my situation - the light is triggered by bumps. says the issue turned out to be a poor connection with his battery. not sure where moisture comes into play. i've heard theres a trans control module and could possibly be getting wet. my passenger floor does get wet when it rains too.