From: hls on

"Bill" <billnomailnospamx(a)> wrote in message
> "hls" <hls(a)nospam.nix> wrote in message
> news:RuqdnUQhhYNB2FvWnZ2dnUVZ_j2dnZ2d(a)
>> "Sara Brown" <SaraTGinMD(a)> wrote in message
>> news:7d8170a0-092a-4c39-8346-98670bedacca(a)
>>> Are the 3-speed and 4-speed transmissions from a 1994 Caravan with the
>>> 3.0 engine in any way interchangeable? I ask because the 3-speed in my
>>> brothers Caravan is shot and someone offered me a working 4-speed also
>>> from 94' Caravan with a 3.0 engine. I was thinking since it is the
>>> same van and same engine somehow both transmissions must bolt on the
>>> same way. Or is there a lot more involved in this than I am thinking
>>> of? Thanks in advance.
>> Sara,
>> I dont know. I suspect that if the 3 and 4 fit this engine in general,
>> then
>> either would probably bolt up, BUT the PCM might have to be changed
>> as well.
>> These things are sometimes just not as simple as they once were.
> Right... It is like installing something new on your computer. You connect
> it, then need to add/change the "software" to make it work with the rest
> of the system.
> And in the case of automobiles, if it was not an original factory option,
> that software is not going to exist.

If you exchange enough parts, you can probably make it work, but that
might include the wiring harness, the powertrain control module, and
Heaven only knows what else.

Software is another issue....sometimes softwares can be updated by
flashing the new info into the system, but the point is that swaps like
this can bring on a lot of headaches.