Loc: Mesa, AZ
Oh no, jeep parts!! (Or, my new drivetrain...)
03/23/04 02:50 AM
Ok, I finally broke down. I've been dinkin around with figuring out a tranny/crawler box/t-case using Isuzu parts for the better part of a year now and I just threw in the towel.
I was gonna use a 4L60-E with the Isuzu t-case. It's all 27 spline and would mate together with some semi-simple adapters but:
1) The Isuzu t-case just doesn't have the reach to clear the 4L60-E pan (although it could be possible with a 2-piece driveshaft.
2) With a crawler box made from another t-case, it would space the t-case back far enough to work, but would leave me with about a 12" - 14" rear driveshaft in an Amigo. Way too long
So, after seeing a post by Jerry a couple months back about Isuzu switching auto tranny's in '03 or '04, I'm going with an Aisin Warner A340 variant instead. This was the tranny I wanted to switch to a couple years ago, but didn't because I was planning an engine swap and didn't want to dump a lot of money into a drivetrain I couldn't use after the swap.
So, the specific version I've got is an AW-4 from a (gasp) '98 Cherokee. An EBay steal for $108 from a junkyard with 12,000 (or so they said) miles on it. I coulda also used a Toy A340-F and used Toy t-cases/Marlin crawler as well. There are *TONS* of these AW-4's out there though, and most are pretty cheep. The Toy A340-F's are much less available from what I found, and usually cost substantially more.
With the jeep bell and torque converter removed (lying on the floor in the pic), I bolted up an Isuzu 2.6 bell housing that Jerry has selfishly loaned to me :) The hyraulic t-case version of this tranny BTW, is the 30-80LE used by Isuzu in the 2.6 Trooper. Also used by Toyota, jeep, Mitusbishi, etc., in one form or another. So, with a flexplate and coverter for the 2.6, I'll have a bolt-up auto.
This has a 23 spline output and the NV/NP 6-bolt round t-case pattern, so an obvious t-case is the (egads! another jeep part!!) Dana 300. It'll bolt right up. Hopefully, I'll be able to use the Isuzu flanges on it though (from an Isuzu D44 pinion) instead of the strap type yokes that are stock. I'll find out when the t-case gets here this week. I'm also gonna twin-stick it. I've got a good friend here with a built CJ-7 and I went out with him a couple weekends ago. I love being able to put it in front wheel drive, pull the e-brake and pivot around a rear tire :)
I also broke down and spent a sizeable chunk of my budget on something I swore I'd never spend money on. I did get a very good price on it used, but still, it was more than my engine/tranny/t-case together. Me gots a 4:1 Klune-V This will give me 2 very good ratios (33:1 and 51:1) with the auto tranny, and a stupid low of 132:1, which probably won't be of much use other than to have fun seeing if my brakes will be enough to stop it at idle
Again, it's a bolt-up (I'm really not used to this. Kinda cool actually...) to the tranny, the D300 will bolt up to that and I'll be able to clock both the Klune and the D300 wherever I need without any extra clocking rings. This whole combo comes out very short too, and will fit the Amigo pretty easily I think.
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.
Finally, for my shifter... One cool thing about these tranny's is the solenoids for controlling the shifing are simple on-off devices. Not frequencey / PWM type things the GM series tranny's have used. That means that shifting can be controlled pretty simply with some switches and 12v relays. Even better, the 2 solenoids that shift from 1st - 4th gear are Gray code, meaning only 1 solenoid changes state from 1 shift to the next. There is a 3rd, TC lockup solenoid too. Line pressure for the shift is dependant on throttle position and is done mechanically with a cable to the throttle body.
Now the shifter..., ooh, I really love this... here...
is a Volvo Geartronic shifter from an S60. A perfect match for a manually shifted auto tranny. Once in 'D', the lever slides to the left and you can bump it fore and aft to upshift and downshift sequentially. This lends itself very well to a DIY cobbling of microswitches and relays to shift the tranny. I'm gonna hook the 'W' (winter mode) button up to be the TC lockup as well. I'll also remove the Reverse lockout stop so that if I ever do need it, I'll be able to slam the shifter over and up against the stop for an instant 1st -> Reverse shift.
Crap, this has been long-winded. I'm just kinda excited over this. I really want to have this for Moab this year, but it may be a bit much this late in the game. Among other things, I'll need to build a whole new console around the shifters. We'll see....
Edited by houlster (03/23/04 02:52 AM)