Paddle Shifter Project Questions

Hello! This post was originally in the Gen 2 section, but it was recommended that I take it to Gen 1 due to the A340 4-speed being more prevalent in older models:

This is a long post and probably ambitious undertaking, so I appreciate if you are willing to read the whole thing! If not, there was your warning!

I am very interested in a project to have paddle shifters for part-time, full manual control over the transmission. I have a 2.7L Auto 4x4, so it is a dog, but a lot of the frustration is due to the transmission never knowing the correct gear to select. A lot of people would suggest a manual swap of some kind, but I want to retain the automatic, as I have other vehicles with other types of transmissions and like variety.

I have done a solid amount of digging already, and have found some threads that exist utilizing arduinos and DIY circuitry, but I want something robust enough to trust offroad. Other issues with the DIY threads I have found is most of them do not have good control of the TC lockup, dont allow for engine braking, and critically only control your highest gear (as opposed to your selected gear). This is effectively like using the stick to shift down to 2, where the TCU can still decide it wants to be in 1, since it is lower.

Older threads suggest using a suprastick setup, or latent solutions equivalent (old auto Supras used the same transmission apparently), and while people seemed to have some success with these, they are no longer sold and may present similar issues to the DIY setups in regards to TC lockup. I have also heard of a KDOG setup, but from what I can tell these never made it to the market officially in any major capacity. I have seen a couple youtube videos of both loosely in action, but nothing majorly convincing, even if I could get my hands on them.

This leads me to my current best options that I have found, both of which I believe are standalone TCUs that would require total disconnection of the factory TCU and throw a check engine light:

RAD Designs Winter's shift controller -

https://www.radesignsproducts.com/products/winters-shifter-electric-to-manual-control-kit

This is made directly for the A340E/F, and allows for a switch to change between auto/ manual settings, which is ideal. However, they seem to be designed to work pretty directly with floor "sequential" shifter units (not +/-, but manual select). It seems to me that these work with many momentary switches, but most paddle setups are just a single up and single down momentary closed signal. It may require custom circuitry to integrate this, regardless.

COMPUSHIFT -

https://hgmelectronics.com/pages/transmission-controllers

Also can be configured specifically for the A340. This seems much more highly developed (and pricey) and has supporting software/ apps for adjusting shift points and times in auto, various modes, etc. However this also only works as a standalone. These do come with compatible paddle shift kits, but are not usable with factory wheels or airbags seemingly.

Both of these options suggest that they can properly account for engine braking/ TC lockup, and can be used manually and automatically.

Edit: I found a third potential option. It is called the Nifty Shifter and is used for Jeep AW4 transmissions, which are basically the same Aisin box but rebranded for Jeeps.

Nifty Shifter -

https://nickintimedesign.com/product/aw4-nifty-shifter-jr-v1-97/

So far this seems like the closest to what I would want, with minimal custom circuitry required, but with it being compatible specifically with Jeeps, I worry I may run into other issues with harness pinouts (example, the signal to bypass the check engine light and prevent limp mode is probably totally different on a toyota ECU).


In terms of actual paddles, I have seen multiple people swap out 2014-2019 Corolla steering wheels on their tacomas, tundras, and ravs. One thread for a Tundra even goes through the pinouts/ clocksprings of making a factory Corolla paddle shifter wheel work with the tundra's Sport shift transmission, which is much easier as it natively handles the +/- functionality on the shifter console and can be tapped into electrically. The A340 is solenoid controlled (2 for 4 speeds, 1 for lockup), so it is not so simple in my case.

Ideally I would retain stock-ish look, airbags, and dependability.


So, my questions:

• Does anyone have experience with any of the controllers listed above that they could share with me? Compushift, Nifty Shifter, RAD Designs, KDOG, Suprastick, others?
• Has anyone done something similar, and I am just missing the thread?
• I have pinouts for both Corolla and Tacoma wheels, but is there a resource for me to know signal types (voltage or communication type of signals from wheel buttons)
• I believe the ECU and TCU are not very closely intertwined, meaning I can run an ECU tune without it impacting my programmed shift points, etc. And by removing the factory TCU, it should not impact engine performance. This seems obvious, but I dont want to assume. Can anyone verify from experience? I have an OTT and want to make sure I wont interfere with that.
  
• Any other advice? (besides that it isnt worth the effort, because I already know that lol)

Thanks for making it this far, anything constructive is greatly appreciated. I know this isnt a conventional project, but it is reversible and I like a challenge.

 

Ho boy, what a post to unpack. I'll condense my thoughts:

The A340E/F can be split into two control models. One only requires 3 roughly 1.5Amp outputs, the other requires some additional PWM work for the accumulator (?) solenoid. I don't know which one you have, and all my experience is with the former. Coincidentally I just, today, took full control of my transmission with my Haltech.

If all you want to do is have the option for a temporary, manual override, I would highly suggest DIYing using a simple microcontroller. All you'd need for the simplest mode (assuming the former style trans) is two buttons (up and down) which will cycle three outputs between high and low which control the trans solenoids.
1st gear and lower = S1 on, S2 off
2nd = S1 on, S2 on
3rd = S1 off, S2 on
OD (4th) = S1 off, S2 off
S3 is purely for lockup and I'd probably just consider it a 5th gear state for simplicity.
You'd also want a feedback input for each of the 3 solenoid circuits so the microcontroller can track what gear state you're in so you can switch between modes on the fly. You'll want a set of relays that intercept the factory wiring, and a set of Solid state relays to drive them from the manual/microcontroller side. Then some simple coding that tells it what to do for each state, the wiring, then you're done.

Later, you could splice in RPM and TPS to automate lockup if you wanted.

I'm assuming you have the more advanced transmission though, so you'll need to read up on the additional requirements for that. I think you'll need TPS right off the bat.

 

This is great info, thanks! So youre able to control the transmission using your ECU, rather than having a separate ECU and TCU? That is an interesting thought! In your particular case, when you are in manual control, you press a button to manually toggle the third solenoid and lockup the TC, meaning you can lock in any gear instead of just overdrive (4th)? Is there any downside to this besides a drop in RPMs?

It seems like with most of the controllers I have found, they still require you manually select gears in a non-sequential fashion with 3-4 sets of switches, rather than an up/down with logic to create the correct solenoid output. Which would kind of make it pointless in my case, as I would still need to do a micro controller to piggyback anyways.

 

No, I actually don't have paddle switches installed yet (idk if I ever will since I'm scarce on inputs but we'll see), I just have basically OEM+/full control of shift points. The first gens have both functions in one ECU btw, idk about the others.

Technically yes though, you can have lockup in any gear, but it's said you do not want to be in high load conditions in lockup, so the only practical time to lock it is in low throttle in your highest gear.

But ya I have never seen a full plug and play solution for this. Though again, it wouldn't be that difficult... relatively speaking.

 

Cool beans, sounds no matter what I am programming a controller myself, so I will start there. Cheaper anyway, was just really hoping for something aftermarket that was thoroughly vetted... just too much of a niche request, I suppose!