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What Is the Tcase Input Spline Count on an A340F Auto Trans?

Sean

Sean

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Searched and didn't find anything on this here on IBB. Very surprised by that. I guess the A340F was used in 4 cyl Toyota 4x4 pickup trucks in the US from '85 to '95, in 4 cyl 4x4 Tacomas from '95-2015, in 4Runners from '85-2004, T100s and early Tundras. Apparently, it's not computer controlled either.

I'm looking to potentially swap an auto into my Toyota powered buggy that currently has a W56C manual trans and 21 spline input on my upgraded Advance Adapters crawl box hooked to a 5.0 Atlas II via an OTT 32 spline adapter. The A340F might be a candidate.

However, I think the A340F uses a 23 spline input and I'm not 100% sure I can swap my 21 spline to a 23 to be able to keep that expensive tcase/underdrive set up I have now.

So....long story short, does anyone know what the spline count is for the tcases that plug into the back of the A340F?
 
I think you are incorrect on a lot of those facts.

A340H was used pre-Tacoma.

I believe all are computer controlled.
 
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A340F should be 23 spline, you will probably need the adapter to a tacoma trans from advanced adapters and a 23spline input. I would call advance adapters and see what they say for parts needed
 
rockota said:
I think you are incorrect on a lot of those facts.

A340H was used pre-Tacoma.

I believe all are computer controlled.
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I am going off a wiki article....so you KNOW there's a lot of room for error, lol. To be fair though....it did say (as I did) that they were used pre-Tacoma ("used in 4 cyl Toyota 4x4 pickup trucks in the US from '85 to '95,....."). And yes, I was totally wrong about electronic controls....there are A series transmissions that are fully mechanical/hydraulic but are the exception, not the rule.

Source: Toyota A transmission - Wikipedia
 
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Thanks guys....I figured it was 23 but wanted to be sure. Thought with it being found in some 4 bangers I might get lucky and find one with a 21 spline like in the 4 cyl manuals.
 
Sean said:
I am going off a wiki article....so you KNOW there's a lot of room for error, lol. To be fair though....it did say (as I did) that they were used pre-Tacoma ("used in 4 cyl Toyota 4x4 pickup trucks in the US from '85 to '95,.....").
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I’m 87.45% confident the F didn’t show up until 95…. The H was prior, and it’s a whole different animal with its “integrated” transfer case design.
 
Yeah...this PBB thread is far more informative:

www.pirate4x4.com

A340 Transmission issues and FAQs

Since I bought my 88' 4runner a few weeks ago, I have been having some periodic shifting problems with it. Its been getting worse as of late though, so I started looking for answers on the web. Anyway, take a look at what I have been able to find out and diagnose with the help of several sites...
www.pirate4x4.com www.pirate4x4.com
 
Not exactly what you are wanting, but I am running a A340 with a Aw4 output shaft and tail housing. This bolts directly to an atlas. No computer, just switchs for the shift solenoids and lock up.
 
Also look at the AW4. Since you’re planning on running an atlas it may be a better option with out the need of an adapter. An AW4 and A340 are both built by Aisin and are very similar. You can use a Toyota a340 bell housing to connect it to a Toyota engine. I’ve done some research on them because the are plentiful in my area and have more options for doublers and driver drop t cases. I think you don’t need a computer to run an aw4 but I don’t remember for sure. I don’t have my notes in front of me to share exactly what’s needed.
 
Crawlin4runner said:
Also look at the AW4. Since you’re planning on running an atlas it may be a better option with out the need of an adapter. An AW4 and A340 are both built by Aisin and are very similar. You can use a Toyota a340 bell housing to connect it to a Toyota engine. I’ve done some research on them because the are plentiful in my area and have more options for doublers and driver drop t cases. I think you don’t need a computer to run an aw4 but I don’t remember for sure. I don’t have my notes in front of me to share exactly what’s needed.
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AW4 has a different input shaft and converter. You have to swap those too.
 
Went the same route when I pulled my r151 and swapped to an A340F. I used the AA 50-5710 adapter to mate the Atlas II 4.3. I found the trans for cheap and couldn't find any AW4s locally at the time to use or rob any parts off of. Then pick up the RAD designs controller to control the trans. 3 wires and a key 12v connection and you are good to go.
 
Boomtacoma01 said:
Went the same route when I pulled my r151 and swapped to an A340F. I used the AA 50-5710 adapter to mate the Atlas II 4.3. I found the trans for cheap and couldn't find any AW4s locally at the time to use or rob any parts off of. Then pick up the RAD designs controller to control the trans. 3 wires and a key 12v connection and you are good to go.
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What is the spline count on your input for the Atlas? I'm a 32 spline input....
 
I call it the Jeep 23 spl as it differs for the Toyota 23 spl. The spud shaft in the AA 50-5710 kit is the conversion point.
 
That's what it looked like when I searched that part number. I'd imagine AA could make a custom spud to my 32 spline input.....
 
a new input gear assembly may be less expensive if they don't have a spud designed already. I've never priced that out so..
 
Boomtacoma01 said:
a new input gear assembly may be less expensive if they don't have a spud designed already. I've never priced that out so..
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Entirely possible....but then I start questioning trying to keep the Toyota drivetrain and start thinking Chevy V6 and TH350 or similar.
 
Bebop said:
Which still won't fit a 32sp


To my knowledge, they wont
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No but apparently there are 27 to 32 spline conversions, so if they won't make a custom spud....
 
It takes 30mn to change an input shaft in an atlas. Why wouldn't you do that instead?

They are all in stock too.
 
Bebop said:
It takes 30mn to change an input shaft in an atlas. Why wouldn't you do that instead?

They are all in stock too.
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Well, if you look back at the beginning of the thread...the point originally was to be able to keep the factory ratio 2.28:1 reduction box in front of the Atlas. If I do have to lose that, then I might as well swap the input to whatever I need....though a 23 spline Toyota input would seem a substantial strength downgrade from the 32 spline I'm running now at that particular joint. That said, all of this is sort of in a state of flux since I have so many other projects in front of this one.....it was more of a thought exercise to see if it was even feasible and how easy/difficult it might be. It's sounding like a Chevy drivetrain may be a lot simpler; just more expense.
 
Sean said:
Well, if you look back at the beginning of the thread...the point originally was to be able to keep the factory ratio 2.28:1 reduction box in front of the Atlas. If I do have to lose that, then I might as well swap the input to whatever I need....though a 23 spline Toyota input would seem a substantial strength downgrade from the 32 spline I'm running now at that particular joint. That said, all of this is sort of in a state of flux since I have so many other projects in front of this one.....it was more of a thought exercise to see if it was even feasible and how easy/difficult it might be. It's sounding like a Chevy drivetrain may be a lot simpler; just more expense.
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Sorry, should have red better.

Just ditch the doubler, you won't need it with the auto.
 
Bebop said:
Sorry, should have red better.

Just ditch the doubler, you won't need it with the auto.
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Probably would never use the doubler....but would definitely use the 2.28 vs. the 5.0 at times.
 
Bebop said:
Sorry, should have red better.

Just ditch the doubler, you won't need it with the auto.
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BTW, thanks for letting me know about how easy the swap on the Atlas is. I honestly had no idea what kind of process was involved, but if it's fairly straight forward, if I do have to ditch the front case, then swapping the input to match the TH350 I already have would make sense. Although, it may make more sense to sell the TH350 and buy one more TH400 (since I have to buy 2 now for other projects). Pretty sure the TH400 output matches my Atlas input. I know both are 32 spline....but I'm not positive that the diameters are the same. I seem to remember mine being a 1.5" 32 spline.....I'd assume the pressure angles are the same.
 
Sean said:
Pretty sure the TH400 output matches my Atlas input. I know both are 32 spline....but I'm not positive that the diameters are the same. I seem to remember mine being a 1.5" 32 spline.....I'd assume the pressure angles are the same.
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They are the same. You're good there.
 
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