5 speed auto

[scottryana]

Running the engine on a stand alone is easy. Up until recently it was very difficult to run the engine and trans on the same computer, they just didn't have the outputs or the ability. In the near past the computers have gotten more sophisticated so you can run the engine and trans, but few have actually done it. The problems start happening when you look at all the features outside of the engine and trans, i.e. 2nd gear start, a/c compressor idle up, transfercase and axle locking logic, etc. I am sure they could all be overcome it is just a matter of finding a computer with enough I/O's and taking the time or paying someone to do it.

 

[WrongsideDaily]

Can anyone here measure the extension housing from the a750F from a 100 series? I'll buy you a beer. Seriously, I'm really hard up for this measurement as it'll help me s*** or get off the pot. Seems the a343 extension housing to HF2A for 80/100 is 125mm, I just need to know what it is for the a750f. I'm trying to avoid spending unnecessary money if possible as I got something in my head that I think will work and this is the one thing holding me up.

I know the a343/a750 share this bearing, I just need to know if the housing is the same length as these so I can make my play

 

[azngarage]

 

[WrongsideDaily]

View attachment 3445778

I'm gonna be honest, having a difficult time reading that in imperial at that angle, but it looks like it might be where I need it to be! Thanks!!!

 

[azngarage]

 

[WrongsideDaily]

@azngarage you're the effin best!

Alrighty, so based on this measurement I'm thinking I can slap the a750f output shaft in an a761e, mod my 100 series extension housing from my a343 ever so slightly, and make myself an a761f to slap behind a 3UZ with an HF xfer case. Time to throw some money away!

 

[azngarage]

Interesting. Is there a reason 3UZ and not 2UZ.

 

[WrongsideDaily]

@azngarage absolutely there is, multiple!

1: weight
2: power (even before remapping ecu the 3uz makes slightly more, albeit slightly higher up)
3: 2uz ECU doesn't control a761
4: ECU has been modded to ditch EVAP, cats, remapped for more limiter as well as fuel/ignition/cam timing, trans control remapped to hold gear, shift firmer, shift higher
5: Because I have this stuff sitting on the floor and something needs to be done with it.

 

[sbman]

I've been through this thread a couple of times and wanted to try to recap where this idea stands.

I believe all of the following to be true based on what I've seen in this thread:

• Control of an A750F can be handled by a Compushift unit
• 1FZ-FE ECU will throw codes when you unplug the original A343F (I think this can be solved)
• No bellhousing exists to bolt any A750F to a 1FZ-FE
• The 1FZ-FE engine bolt pattern is completely unique (not shared with any engine that came with an A750F)
• The transfer case from an 80 series A343 application will bolt up to an A750F from a 100 series

In the pictures of the bellhousing comparisons in this same thread at:

https://forum.ih8mud.com/threads/5-speed-auto.818217/post-10016285

It looks like the 1UZ bellhousing that comes with a 100 series A750F is both shorter in length than the A343F bellhousing and smaller in diameter than the 1FZ-FE engine bolt pattern with a top (valley) mounted starter.

It seems like a flat plate style adapter to use the 100 Series A750F including the bellhousing could be created to mount it up to the 1FZ-FE. Flat plate bolted to 1FZ-FE and A750F bolted to flat plate.

Designed correctly, this would add the missing length from the A750F bell to get the output end of the A750F in the right place length wise so driveshafts would be in the same location.

Accommodation for the starter would be an issue, the starter would have to mount to the flat plate adapter and possibly have clearance ground/cut into the A750F bell to get the nose of the starter to clear since the original application had it up in the valley of the V8 it was attached to. You'd also need an extension ring on the 1FZ-FE flex plate to space the A750F torque converter out and adapt to it's bolt pattern.

So it seems like with two custom machined pieces this could physically bolt up. Does this sound like an accurate summary?

 

[WrongsideDaily]

@sbman ain't gonna work. You gotta keep in mind the converter needs to fully seat

 

[sbman]

@sbman ain't gonna work. You gotta keep in mind the converter needs to fully seat

You would have to space the converter out from the flex plate as I mentioned. You'd be making the back of the 1FZ-FE look like the 1UZ as far as the trans is concerned.

 

[WrongsideDaily]

Bell housing flange thickness is like 4mm and change thinner on the UZ bell, as well as the opening is 20mm larger. Also, the way the FZ bell slopes in leaves not enough room for converter physically as far as circumference

 

[WrongsideDaily]

You would have to space the converter out from the flex plate as I mentioned. You'd be making the back of the 1FZ-FE look like the 1UZ as far as the trans is concerned

The converter can only fit in the bell housing so far, the problem lies in adding more distance between the bell and the pump. That's not going to work, physically. You CAN make this work if you can make a hybrid bell housing. P sure that's where this ended.

 

[sbman]

Bell housing flange thickness is like 4mm and change thinner on the UZ bell, as well as the opening is 20mm larger. Also, the way the FZ bell slopes in leaves not enough room for converter physically as far as circumference
View attachment 3448017

That's not what I'm talking about. You put a flat plate on the back of the 1FZ-FE that has a bolt pattern in it for the A750F original bell housing. You use the original bellhousing and torque converter with the A750F. I did see that a bellhousing swap wasn't possible and there is no room on that side for an adapter plate.

 

[mjosoba]

That's not what I'm talking about. You put a flat plate on the back of the 1FZ-FE that has a bolt pattern in it for the A750F original bell housing. You use the original bellhousing and torque converter with the A750F. I did see that a bellhousing swap wasn't possible and there is no room on that side for an adapter plate.

And a spacer on the crank to match the adapter plate thickness?

 

[sbman]

Like this:

Imagine that's a 1FZ with a plate bolted to it, and the inner bolt pattern matches up with the A750F. You'd need a custom flex plate or an adapter for the original 1FZ flex plate to get the clearances right for the converter on the A750F. Since the A750F with it's bell should be shorter in length than the A343 is, the plate also spaces the 750 back far enough to get the transfer case in the right place.

 

[sbman]

And a spacer on the crank to match the adapter plate thickness?

Exactly. Spacer on the crank or on the flex plate. You might want a heavier large ring on the 1FZ flex plate for the weight anyways since the smaller converter is likely to be lighter than the original from the A343.

 

[WrongsideDaily]

IMO, a viable option, but it's worth is probably more inclined towards someone just wanting to make things work that shouldn't with the skillets to do so because they can, yet far from realistic for any real world reason and average person.

Here you can see as already has been covered, the lower two bolts line up. This makes it jig-a-ble within reason as far as my brain works. Get your depth right, lathe, mill, fixture, weld, use full 100 series a750 and it should go together at least.

 

[WrongsideDaily]

Like this:

View attachment 3448039

Imagine that's a 1FZ with a plate bolted to it, and the inner bolt pattern matches up with the A750F. You'd need a custom flex plate or an adapter for the original 1FZ flex plate to get the clearances right for the converter on the A750F. Since the A750F with it's bell should be shorter in length than the A343 is, the plate also spaces the 750 back far enough to get the transfer case in the right place.

I suppose I was confused about where you wanted to sandwich the plate, I still don't like the overall approach. Yeah, I guess that could work, seems a lot less reasonable than building a hybrid bell housing using similar tooling now that you're introducing more overall length which defeats the entire purpose of the a750 being the same length. Now we're talking moving back the trans x member, or slotting it at best. Different driveshaft lengths, etc. None of that makes sense at this point, and tbh I didn't see it making much sense at the inception of the whole thread albeit that's arbitrary I suppose. The way you're describing sounds much less cost effective with much more distance between A-B the way I see it. Additionally you're still gonna have to do more work and custom fixture your t case shifter to the a750f for an 80 series, but that would be for either way you skin this cat, hybrid bell, or adapter

At the end of the day, I have no dog in this fiasco as I just came here for info to make an a761F that doesn't exist. Will I be able to pull that off? Maybe? I at least took a gamble and bought a new a750f shaft from Japan. Does it bolt up? Sorta! Physically the extension housing will, but it will need to be slightly modified which I'm okay with. I'll need to relocate this slot to the proper spot where my pinky is pointing so it matches the trans, NBD

 

[sbman]

I suppose I was confused about where you wanted to sandwich the plate, I still don't like the overall approach. Yeah, I guess that could work, seems a lot less reasonable than building a hybrid bell housing using similar tooling now that you're introducing more overall length which defeats the entire purpose of the a750 being the same length. Now we're talking moving back the trans x member, or slotting it at best. Different driveshaft lengths, etc. None of that makes sense at this point, and tbh I didn't see it making much sense at the inception of the whole thread albeit that's arbitrary I suppose. The way you're describing sounds much less cost effective with much more distance between A-B the way I see it. Additionally you're still gonna have to do more work and custom fixture your t case shifter to the a750f for an 80 series, but that would be for either way you skin this cat, hybrid bell, or adapter
View attachment 3448052

At the end of the day, I have no dog in this fiasco as I just came here for info to make an a761F that doesn't exist. Will I be able to pull that off? Maybe? I at least took a gamble and bought a new a750f shaft from Japan. Does it bolt up? Sorta! Physically the extension housing will, but it will need to be slightly modified which I'm okay with. I'll need to relocate this slot to the proper spot where my pinky is pointing so it matches the trans, NBD
View attachment 3448062

It was said previously that the A343F and A750F cases are the same length. The bell on the 750 is shorter than the bell on the 343. That would make the 750 with it's native bellhousing shorter overall than the 343 with it's original bellhousing, thereby giving space for the adapter plate and putting the transfer case in it's original position.

This is a pretty common operation on other vehicles.