In article , F.
Hayek wrote:

In article ,
Ernie Leimkuhler wrote:

I though these adpater bell housings were already available off the
shelf for a few $100.

Not for this application. What I'm trying to do is mate up a Toyota
Supra Turbo 7M-GTE motor with an R series transmission in a Toyota
pickup truck. The Turbo Supras also used R series trannys but they had a
longer inputshaft (+30mm) than the R series truck trannys (same diameter
and spline though). The Supra tranny is undesirable for 4x4 trucks
because it has a higher first gear and you can't change that gear
without changing the input shaft to a truck input, which would then be
too short. The truck trannys will bolt right up to a Supra bellhousing
but the input shaft will be 30mm too short. A pilot bearing adapter that
moved the pilot bearing 30mm out to the input shaft seems like it would
interfere with the clutch disk hub.

The most desirable R series truck transmission has a 4.31 to 1 first
gear and the Supra tranny has a 3.21 to 1 first gear.

The 5 sp. transmission used in a 1996 or later Tacoma is also an R
series and it will also bolt right up to the Supra bellhousing, but, it
has a different tail housing (for mounting the transfer case). A company
called Marlin Crawler makes an excellent adapter to mate the correct
tranfer case to this transmission for $349, but (yes another but) the
first gear ratio in the Tacoma trans is 3.89 to 1, which is better than
the Supra ratio and not as good as the earlier transmission with the
4.31 ratio. There is no gearset available to change the ratio in the
Tacoma trans to a lower ratio as Toyota changed the helical cut on the
gears in 1996.

It would be possible to have a longer custom input shaft made, but these
inputs also have and integral bearing race and a gear; they are not just
a simple shaft, so a "one off" job might be prohibitively expensive
(although I'd welcome input on that).

The easy answer looks to be a stock Supra bellhousing and clutch, Tacoma
transmission, a $349 transfercase adapter and live with the 3.89 first
gear. My only worry is that the Supra motor, while it has good low end
torque, displaces only 3.0 liters and probably could benefit from a
lower first gear in this application. I guess it works well enough in
the Tacoma behind the 3.4 V6, but heck I want to do better than stock :-)

Fred

Believe it or not I get it.

A custom Bellhousing could be done, but it requires high skill.
I know I could do it, but I would have trouble finding more than 2
other people I know who could do it.