Aisin Transaxle

[Bob]

I wanted to post here because over the last year, I designed my own conversion pieces, C5 Bellhousing adapters, Big brake swaps for my Chevy 5.3l Porsche 944. I am about to start my custom transaxle using a Corvette C5 differential and before I do, I wanted to pick the transaxle GURU brains here.
First off, without any doubt, I can install the C5 differential on the end of ANY Aisin 5-speed with a Jeep or Toyota 4x4 tailhousing and custom adapter plate and shaft extension....

This setup would be a piece of cake in a 928 (has no cross torsion tube for traling arms) which I will later do a Chevy V8 conversion to......

However the 944 has a cross torsion tube that would require me to cut the rear floor pan and extend the adapter tube and shaft to the C5 differential.... to look like this ......which can be easily done, but floor pan modding will then need to be done under the back seat.....

 

[Bob]

Trying to learn the image edit function so bare with me....

My real question to you guys is if the gearing/shifting mechanisms would still function correctly if I were to mod up an Aisin box like these....The first pic is the R154 from a Toyota Supra.....

This is what I would like to do if the gear/shifter mechanisms would still work with the 1-piece input shaft installed and the countershaft teeth removed (this as I understand has the gearing ratio involved normally).....

IF this mod to the box can be done and gearing/shifting still work with the output shaft now exiting front, I would be able to mate the C5 differential on the face and save cutting into the 944 floor pan.....

I am serious about this project and want all the input I can get before I pull the trigger on the first arrangement (C5 differential behind Aisin 5-speed)...
Thanks ahead of time, Rob

 

[Jac Mac]

Bob, this is taking forever to load @ my end due to exceeding B/band limits( my problem, not yours ), will look back in on friday when back up to speed,,,,,,,,

 

[Jim Cowden]

How will you select 4th if its a 1 piece input shaft.
Will you not need another set of gears to give you 1 to 1 or there abouts.
Deleting the selector hub on the input and output shaft has deleted 4th gear or am I not seeing something?.

I think your diff may hang to low.
For the amount of work you are thinking about You will not be happy with them ratios IMO.

I have looked at the same problem several times over the last few years, it always came down to attaching that pinion.
I came to the conclusion as others have before me it was more economical to use a winters quick change diff C & P ,drive straight out of the gearbox output shaft with the QC gear set and a shaft from there running forward to the diff if you get my drift.
I feel that the more mods you do to the box ,it starts to become special and when you break it you have to park it.
If you keep the core of the box STD then it is less of an issue in my mind.

A diff housing and extension housing casting is required and an amount of machine work.

Keeping it short is the trick.

Ill be interested to see how you go.

Bloody hell jac you have a lot of posts, you need to get out more.

Jim

 

[Jac Mac]

Bob, your second photo layout is not practicle... to do it this way all the ratios & loads would be reversed--- old 5th would become low gear, old 3rd would become second, 2nd becomes 3rd ( & overdriven ), 1st becomes 4th ( top & overdriven ). None of the ratios are likely to be suitable as all the previous indirect ratios are the combo of ..[ input/layshaft ratio x gear selected ]

Jim C... yes I know, get no encouragement from the site either , get up in your post count & they stick that..I HAVE NO LIFE... moniker under your name, [dont you just hate it when barstewards tell you something you already knew]...unless of course you pay to have that wobbly star thing like you've got on yours, might have to do the cold turkey deal & leave.... or start a barely concealed product selling / complaint line of threads like Craig G & get kicked off/banned... that could be arranged & would help stave off the addiction/cravings to return.....

 

[Jim Cowden]

Dont leave Jac ,none of us have a life but we all have passion.

Bob
I just looked in a few trans axle manuals and they are free spinning 2 gears on the pinion shaft (your cluster or lay shaft) with another syncro hub to make the gear paths work.
(I didnt study it to any great length as that will be your job.)
If that is the case it would become very cost prohibitive, Having said that I wonder if there was a very strong front wheel drive box available that the gear set could be used but that could be getting away from what you are trying to do as you would need to cast a case.

Is there a FWD manual box behind a v8 or v6 that anyone knows of.

Jim

 

[Jac Mac]

Bob, why not simply use the torque tube/trans(6 speed) & diff assy out of the latest vette's, no adapters required other than your 327 to later chev bell housing if necessary.

You seem to be making a lot of extra work for yourself by trying to use the Aisin trans.

You could also use an IRS 8.8" ford + Richmond or TKO whatever direct coupled to achieve same result.

 

[Bob]

I'll have less than 2 grand with an brand new shorter all alloy torque tube when I set it up like the 2nd pic and the fact that when I convert a 928 auto to this same set-up, all I will need is a 1" adapter between the 5 speed and C5 differential. I was figuring that doing the setup with the C5 differential in front of the 5speed would be more hassle than just cutting the rear 944 floor pan. So thanks for all the replies. I will post up some pics as I go. I'm short a wiring harness and exhaust for the 944, then I can proceed to frag the 944 NA tranny.....which won't take long.