will an 89 auto tranny, swap into a 92?

They should both be A4LD's I would think and just simply swap.

no, the 89 does not have the computer controlled lockup. The later model tranny has different internal controls. It will phyiscally fit, but i bet the 3/4 shift wont work right, and you will get a CEL.

Dr.

A CEL is "check engine light" As for spliceing wires, Im not sure, i would fine a harness diagram for both the 89 and the 92 and see which wires do what. i think the 89 only has 2 wires though. Im not a Automatic expert though so i really dont know. You might ask Bhuff, i think he has more knowledge of stuff like that then i do. I Have the 92 wiring harness diagram if that will help you let me know and i can email it to you. I dont have an 89 diagram though.

Dr.

Shinlee, I've had the experience of doing this, basically a 90 A4LD into my 93, same as ur situation. Like Elusive said, it does not have the computer controlled lockup, that's where the lack of that third prong comes in on your 89 tranny. If I remember correctly that third wire just controls the torque converter lockup solenoid, and the other 2 are for the 3/4 shift and a ground I believe, which u do have on ur 89. I never got a CEL off of running just the two wires, but if u run a diagnostic test and get the codes out of the car, it'll throw some code about that solenoid malfunctioning.

You have two possibilities:
1)Hook up those 2 wires the 89 had, just use the connector from the 89 and splice the correct 2 wires to the 92's wires and terminate the 3rd. The side effect I got from that is a nasty jerk from the torque converter locking pretty harshly, usually when it's not supposed to. You'll really feel it, even just tapping the accelerator with your little toe around 45-55 mph. Doesn't cause any serious driving issues, it just gets really annoying pretty quick, lol.
2)Don't hook up the wires at all. I ended up doing this after awhile because the jerking got pretty bad. This will run the car in closed loop so that it doesn't lock the torque converter. I read through the ford factory cd and what happens when you do this is that 3/4 shift solenoid goes into "Failed On" mode, and the side effect from that is that u'll get a little less acceleration from a stop (it is noticable, but if ur lookin to bark some tires, an A4LD isn't the way to go anyway, lol). Why this is, I'm not entirely sure, I thought for the longest time that the converter was just crap and slipping when I hit the gas, but this actually is a known issue w/Ford. This will also get you a little less efficient gas mileage in mid cruising speeds, as the whole lockup idea was intended to help that. Not a serious amount, but less than you'd be getting otherwise.

I got a little tired of both ways, and it'll make u REALLY think abt just swapping to a t-5, but it will definately run the car, and it will shift through all the gears. Hope this helps!

Yea, it just kicks hard when the torque converter locks up. The car shouldn't jump around or anything, u'll just feel a hard thud. I'm pretty sure the reason for that is the converter is supposed to lock when the engine and wheels are spinning at the same RPM or close to it, and it's supposed to engage at a certain point to make it very smooth. W/o that wire hooked up it doesn't program the right point correctly and the two turbines are spinning at more of different speeds and that's why you'll feel it. And yea, you'll keep your regular acceleration with the 2 plugged in. Glad to help ;-)

Damn, I'm glad you guys chimed in I completely forgot about the lock up converter. I've slept a pretty long time before I had to think about this stuff.

I think the difference is that the 89 has 2 solenoids for control and the 92 has 3. I got lucky and got a 90 trans. I got the ATSG book and update manual for the A4lD. It changed a lot over the years. You may be able to use the 89 vb on the 92 trans. Otherwise I dont think they will directly replace each other.