after 6 months of screwing around, my transmission works! (with a caveat)
I'm posting this primarily to help someone else avoid eating the crap sandwich that I've had to eat during the past 6 months.
In november, I bought a used 4l30e transmission from vines. I was told that I would need to swap the computer, as the unit was from a 93 325i, and my car was a 92 525i. I wouldn't have bought it if i knew this, but picked it up anyways. At any rate, after realising that new tranny computer wouldn't work without a ground (I had it sitting on the floor mat of the car connected) I was able to get the car to move, but with the transmission program--ie just reverse and 3d gear forward. After spending many MANY hours adjusting fluid level and backprobing the solenoids and sensors with an ohm meter, I finally took the car to a friend of a friend mechanic, who hooked it up to his snap-on box. the results were curious---the only fault the computer said was "park neutral switch".
even curious-er was the fact that he couldn't erase it with the snap-on unit. please note, this transmission, like other e34s, doesn't have a park neutral switch attached to the transmission like many other cars, just the shift selector. at this point, i began to develop an idea. I don't have any data for the cutoff, but knew that some models (later e34s) had the electromagnet in the shifter to prevent one from shifting unless one's foot was on the brake. my car (7/91) does not have this. I figured that the e36 probably picked up this "feature" at some point, possibly before the car that the salvage unit came from was built. the friend's friend and I came to the consensus that two 4l30e's probably were too similar to fry or kill any electronics by hooking up the wrong computer to the wrong unit. PO'd at the situation, I drove to another friend's house and swapped computers, not thinking that it would fix the problem. I figured that maybe I had a dirty/defective range switch, or was possibly going to have to ghetto rig a shift interlock to get the computer to shut up. Drove about 75 meters/yard away and realised that the transmission had actually gone into first!
let me clear something up. I say that the car would only move in transprogram. this is incorrect. usually, the car would get up to 5-10mph and give a nice, hard, unsettling "clunk", and then be stuck in 3rd. i never had that many opportunities to experience this (i didn't try to move the car too much if something was wrong) and that's why i generalised the situation as "start in trans program." i'm hypothesizing here, but i think the whining the computer was doing was because it thought that the car was acquiring speed while in park. if someone can clarify what is going on, i'd appreciate it.
well, anyways, there you have it. you have no right to sue me if your situation is different, but it looks like the 93 iteration/vanos equipped editions 4l30e will work in the 91 or 92 model cars without vanos. i'm mucho pissed at vines at telling me that this combination would work without a hitch when i was told that i was buying a transmission that would work in 91 or 92 5 and 3 series cars. a good 30 miles later, the car is shifting like i remember it, and i remembered why i loved driving this car so much. thanks for the read.
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