transmission interchange

[lanyo]

I need more help on a trans interchange.
My son has a 1994 Voyager with a 3.0 V6 and AOD trans. The transmission does NOT shift into any gear.
We can get a 1989 Voyager with 3.0 V6 and Automatic trans. It is NOT overdrive.
Will this NON overdrive trans fit and work in place of the AOD trans or will it cause any problems with any of the computers in the '94 ?
Any advise will be appreciated.

[mustangmike351c]

I would'nt do it. even if it would work those 41TE tranny's are junk you'll end up with the same thing you already have. if yours wont shift into any gear check your MLPS

[lanyo]

Thanks for the reply Mike but i would still like to know if the non AOD trans will work in the '94 ? please help. Thanks

[GTP Dad]

No the transmission will not work. The computer that controls the transmission is of the wrong type and the trans from the older van is not compatable with the year of vehicle you want to put it into.

[coalminer]

I have done a transmission swap from the 4 speed to a 3 speed, there is no computer that controls the 3 speed transmission. Now both of the vehicles I was working on were 95's. When I did the swap, I had to change the wiring harness under the hood, I unplugged from the bulkhead connector, and went both ways unplugging everything and then putting the 3 speed harness back in, everything plugged in where it should have and everything works. I also changed the engine computer to the one that went with the 3 speed, I dont know if that was different than the one that was used on the 4 speed, but I figured since everything had to come out, I should change it. The only other item that was a little different was the linkage that goes from the throttle to the transmission, there is none on the 4 speed, so you have to take that off the 3 speed motor (not hard to do). The shifter cable was the same, along with the mounts, and the axles, the cooling lines fit also with no problems.

The transmission will work for sure, however I dont know about the wiring harness, if they were both from 92 to 95 you should be ok, but I am not sure about an 89 harness.

[lanyo]

Thank you coalminer for taking the time to explain your answer.
Does anyone else know FOR SURE about the wiring, mainly, could I just "not" hook up the '94 trans wiring, as there would be no place to hook it up on the '89 three speed, or will that cause other problems.
Has anyone made a swap with simular vehicles as I have ?
Thanks in advance for any help.

[coalminer]

I thought about the differences in the wiring, and your speedometer would not work, and the torque convertor would not lock up as the transmission computer handles that in the 4 speed, and the engine computer handles that in the 3 speed. And also the check engine light would more than likely stay on.

[lanyo]

Thanks for the clarification Coalminer.

[wafrederick]

If the speedometer does not work,the transmission will not shift and that is most electronic transmissions shift now,if the speedometer works.The three and 4 speed transmissions have this problem:the spider gear spits out and ruins the case

[coalminer]

The 3 speed is not computer controlled, except for the torque converter lockup. The 3 speed is also a more durable transmission, and it costs alot less to rebuild than the 4 speed.

[stratus]

Originally Posted by coalminer

The 3 speed is not computer controlled, except for the torque converter lockup. The 3 speed is also a more durable transmission, and it costs alot less to rebuild than the 4 speed.

You could very easily add a simple lockup engagement circuit of your own. Use an oil pressure switch in the high gear apply port connected in series with a vacuum switch in the intake manifold connected ti the switched ignition.

[jsinton]

You will also want to make sure the bolt-up to the engine is the same. There was 28 design changes to the A604/41TS trans, some of which involved changing the bolt patterns to bolt to the engine.