Hi, my name is Quintin, and I just recently acquired a 95 4runner with a locked motor. After spending a few weeks reading on the use of the 3.4, I am wondering why nobody simply bolts the 3.4 to the stock 3.0 auto tranny and use both ECU's with a split harness. I have done this many times with other brands where the tranny needed stock input. I will be doing this on my new 4runner here in the near future,(a few weeks). I'm looking forward to laying out the new wiring schematics for you as I build it for anyone else who would like to do the same.
The info you guys pour into this forum is awesome, and sounds like ther's some real mechanics here.
I just went down south to Berea, KY today and picked up a nice great running 3.4 from a pick-up today for $100. I hope to have her in shape soon.

 

Umm because you dont need to.

 

the 3.4 auto is superior to the 3.0 auto tranny. Plus you can add a gear driven t/case behind the 3.4 auto.

 

Plenty of people have used the 3.4 with the 3.0 auto tranny, You don't need to run two computers like UK said.

 

There doesn't seem to be one thread about a simple 3.4 transplant. If there is a lot of people doing it, why isn't anyone writing up the swap specs like they are the manual tranny swap and the 3.4 auto swap. I've read ever post I could get my eyeballs on and everyone says it can't be done, because the the 3.4 motor and 3.0 tranny are not compatible.
Maybe I didn't look hard enough, does someone know someone I can talk to or get the info from?
As far as the 3.0 tranny and transfercase being inferior, that would depend on usage. There's not a thing wrong with my tranny and transfercase. When people talk about this part being stronger than this part, it's all relative. I can't afford to spend another $1000 in parts so I can SAY it's better off with this or that, when what I've got will works excellent.
Should I look in the electronics section for the right swap info for what I want to do?

 

I was going to write a big ole response. Basically fella, search more, your noob is showing. It is possible, it is easy enough, it has been done.
Wiring diagrams are available from the Toyota website. Access is $10 a day. Down load everything you need from the year of the donor and the year you are swapping into. Read the wiring diagrams you just acquired. Read them again. Then print them out and tape them together. Then read them again. It will become clear.