Isuzu guru Dan Houlton at
www.4x4wire.com has infomation regarding the swapping of bellhousings between Aisin automatic transmissions in Jeeps and Toyotas.
-------------------------------------------------------------------------
"A quick run-down.
The A340 is a very popular tranny in different variants. The key thing is that the main body is the same regardless of what manufacture is using it. Things like bell housings, torque converters, output shafts, tail housings and internal clutches, etc, are different depending on what it's in. *ALL* variances are handled in the bell and tail housing. i.e, something with a big, thick TC will account for that with a big, deep bell housing.
You can swap the bell housing that fits your motor, to an A340 from a different vehicle. This will let you physically bolt it up, but you'll need to account for electronics / TCM yourself. Hardware like the TCM and wiring harness may be very similar, or even the same between makes / models, but I'm unsure of that. The programming will certainly be vehicle specific though.
So...
A340H
This has a hydraulic t-case. Not sure what that means, but it is integral to the tranny. You need to pull the t-case apart to get to the bolts to remove it from the tranny.
This is what Isuzu used in the 2.6 Trooper. They called it the 30-80LE
Used by Toyota early on too.
A340E
2wd version of the A340. No t-case, just a 2wd tail housing. Probably different output shaft variants for different manufactures too.
A340F
Used specifically by Toyota I think starting around '94 or '95. This uses a mechanical, chain-drive t-case. If you want Marlin Crawlers, you can use this tranny, his parts/adapters, toy t-cases and whatever bell, TC, flexplate that will fit your motor.
Some are 21 spline outputs (early 4cyl maybe?). Most I think are 23 spline. If you've got parts already, this could be a good drivetrain. To buy all new though, for tranny (used) and a complete Marlin dual-tcase crawler setup with all the adapters need, the dual t-cases, 4.7's in one case, etc., you're looking at *at least* $2500. That's the main reason I didn't go this route, as I have *no* Toy parts starting out.
AW4
Jeep variant. Used a mechanical t-case, usually a NP-231. The tail housing is the common 6-bolt pattern though, so there's a ton of NP/NV t-cases that'll bolt up. Mine has a big sticker that says 30-40LE
It's also 21/23 spline. It seems the cutoff date is around '91. Before that, it was 21 or 23 depending on the engine. After that, they were all 23 spline.
These were used in a couple different models in different years I think. It's been the auto in nearly every Cherokee though. There's a ton of these out there and it's very cheap compared to a Toy A340F.
Note: According to Marlin, the Jeep 23 spline is *not* the same as the Toyota 23 spline. The shaft on the AW4 is about 1" - 1.5" longer than the Toy A340F, but I thought originally you could still use Marlin's adapters with an extra spacer. He says the shaft diameters are different though. Off by 30 thou or something. Spline pitch is probably different too.
AW4's also used 2 different OD ratios. Early ones were the typical .7:1 ratio. Again, don't know the cutoff, but by around '95 or so, all were using a shallower .75:1 OD. If you search the
www.naxja.org forums for AW4, you'll find a ton of info on these.
Theres a bunch more too. The A343 was an upgraded A340. Can't remember specifics though on 2wd/4wd or vehicles. There is also a version behind some big, V8 luxo SUV that uses a much larger and deeper torque converter and a larger input shaft to account for it. That's the only variant that has a different input shaft that I can think of though.
So, in general, if your particular motor used one of these, you could obtain the bell housing, torque converter and flexplate for that motor/tranny combo, and bolt it to any other A340 variant. Use a Toy A340F to run Toy t-cases and Marlin crawlers. Use a Jeep AW4 for NV/NP t-cases, Klune-V's, Atlas II's, Dana 300, etc. "
--------------------
"Now, what's really cool about this (and is what pushed me over the edge finally) is the tidbit Jerry dropped that I mentioned earlier. The '03 or '04 Isuzu's now use the AW tranny again behind the 3.5. In doing so, they produced a new bellhousing to mate the two. This bell bolts to the 60 deg Chevy pattern in the 3.5 block. So, after my engine swap, I'll be able to get a bell housing from Isuzu that'll bolt this new drivetrain to my 4.9 Caddy motor. Will need to figure out a torque converter / flexplate for it, but that's a pretty minor issue I think.
This also means that it'll bolt to several engines (Isuzu 3.2/3.5, GM 2.8/3.1/3.4, Isuzu 2.3/2.6, Caddy V8's including the Northstar, the 3.5 Olds shortstar, GM supercharged 3800, multiple Toyota engines including the turbocharged Supra, the Tundra V8, and on and on), all with factory bell housings. These tranny's have a very good reputation for being strong and reliable. But, with big V8 power, a stock tranny may not last long and will need a HD re-build on it. Built this way, it does last behind 600 hp Supra's, and heavy, TRD supercharged 4-Runner/Tacoma/Tundra/Sequoia trucks as well. "
Dan Houlton
houlster@inficad.com
Links to Dans info and Supercharged Buick 3800 swap:
http://www.4x4wire.com/forums/showfl...fpart=all&vc=1 http://www.4x4wire.com/forums/showfl...fpart=all&vc=1
Pic 1. Dan Houlton's Isuzu auto bellhousing hooked up to a Buick Supercharged 3800 V6. (Photo by Dan Houlton)
PS. Good info JR! There's always more than one way to skin a cat!
Greg
Linear Mode
