PreRunner to 4x4, need help

I've got a 99 prerunner, 2.7 a/t. Diff code of BO7A. Which should be 4.56 g/r. I have the 99 4runner, 3.4 A/T, transfer case, front diff and c/v axles. Question is will the 3.4 trans mount up to the 2.7 motor, or do I need an adaptor plate? Anything else will be helpful.

 

Depends on trans mdl# first off, I know the A340F is for 1st gen. 4x's w/3.4 & 4 runners too, not sure about bolt pattern on 2.7 (4cyl) obliviously it's a different block thinking a plate might be needed , you making the prerunner 4x sounds like, is the 3.4 any good ? You'd want the extra torque of the 6 cyl (its not much more but noticable)

 

Yeah I would like the 3.4 now, but I'm just gonna save it for another project or use it in the future on the prerunner. The prerunner has been my daily driver for almost 11 years now. Not gonna be doing much off roading, just dirt roads and ice or snow. It's a good ole truck, just wanna make it a little better. And both Yotas are 99 models

 

In a nutshell, here is what I learned converting my 2.7L to 4x4, and I used a trans/tcase out of a 3.4L 4Runner.

V6 trans output to tcase input is 23 spline, whereas the 2.7 has 26 splines, therefore a V6 trans must go with a V6 tcase. Also, the tcase from a 2.7L has a 'Forward Shift' tcase lever, where the V6 is 'Top Shift'. Unless you want to cut a new hole (enlarge/lengthen the existing), the tcase shifter will have to be modified and you use the the trans/tcase out of a 3.4L

If the 4Runner had ABS, then the tcase from 4Runner will not have the tcase mounted VSS (Variable Speed Sensor), which can be obtained elsewhere - -but it is much nicer to simply get the tcase with the VSS (Tacoma).

Physically, the 4Runner and Tacoma uses the same A340F trans and (insert model #) tcase. Whether there are different internal valving/gearing issues are unknown to me. Mine drives just fine, seems to shift as one would expect, kicks down on demand, etc. All electrical connectors matched up (though the 2 wires to the VSS had to be lengthened).

You use the bellhousing and torque converter from your A340E (prerunner) trans. Dip sticks are on opposite sides (2.7 Drivers, 3.4 Passengers), and I had to fab a bracket and modify the dipstick.

Also, going back to introducing a trans/tcase from a 3.4L mandates that both the front and rear (forward section only) driveshafts to be lengthened (front) and shortened (rear) - You can use the existing prerunner rear DS - just shorten it. The OE front driveshaft will also need to be lengthened (the same amount as the rear was shortened. My suspicion is the 2.7L engine block is longer than the 3.4L block. Otherwise the tcase wouldn't need the 'Forward Shift' shifter arrangement. In my case all 'adjustments' were 2.5". That's how far forward I had to 'dogleg' my shifter, lengthen the front DS and shorten the rear DS. - But everything else was a piece of cake

 

Awes

 

Awesome man, thanks. Next question would be about the automatic traction control. How difficult would that be to put in the prerunner or is it just a matter of wires to the transmission? I know I will have to use the front hub assembly's for the automatic lockers. Just curious about the wiring. I bought a wrecked 99 limited 4 runner, that's what all the parts are coming off of it helps any.

 

Automatic Traction Control?? Do you mean the ADD activation for the front wheels? Mine is vacuum controlled - see diagram in post #2 of this thread I was pretty heavily involved with TTORA during this time span. Search that forum for username pray4surf for all my trials and tribulations associated with this conversion. It's been converted for 7 years now and nary a problem since.