A340 Paddle Shifters

I've been thinking all day at work about how to integrate paddle shifters with the OEM steering wheel. Do you happen to have, or have access to, a 3D printer? I know Tacomas don’t have much space between the back of the steering wheel and the clamshell, but maybe there’s a way to design a custom bracket that could mount the paddles from the iM steering wheel.

Alternatively, do you think it would be possible to use two momentary push button (MPB) switches instead of the paddles OR use the existing volume up/down buttons on the steering wheel to act as your shift up/down buttons? I've seen some pretty small MPBs that might be subtle enough to mount directly into the steering wheel trim. Could be a cleaner install depending on how tight the space is. If all else fails you could always mount them directly the the clamshell but this would be annoying I imagine as they wont turn with the wheel.

 

Using smaller momentary push buttons might just be the move! Let me make a trip to the store and see what I can find. Youre right, there is barely room for a hand and paddles between the wheel and light stalk, in particular.

I do have a family member with a 3D printer, but they recently suffered a stroke. Maybe in the future I can make a better solution with their help. Might be another way to use a small sliding existing bracket? Great ideas, thanks! I am grateful for the feedback and brainstorming!

 

Okay, so just for testing and the purposes of being able to drive, I used VHB strips to temporarily mount the paddles. It is NOT good enough to be a permanent solution. I am going to take the advice of @tacokarl and get a 3D printed bracket. Contacted my family member and he said he is down to help me as long as I do the design since his motor function is limited as he recovers. Seemed excited for something to do, to my surprise!

So, the really good news is that the pass-through mode works perfectly. I can drive the truck no issues, which is huge because that means I got everything re-assembled without ruining my truck haha! Sort of bad news is, I can only seem to use 3rd and 4th gear in manual control. I am assuming this is an issue with an electrical connection or ground on Solenoid 1, because the commands and gear readout are still sequencing down to 1 and 2. About to storm, but I consider this a successful test and hopefully something easy to troubleshoot! They all worked when individually testing circuits, but I knew it wouldnt work getting everything back together on the first try... never works the first try!

When I put on the supercharger kit, I will have to remove the wheel for gauge pods again. I might just swap the entire wheel from a corolla iM instead of just the paddles when the time comes. Would be cleaner and looks stock. I am gonna keep my eyes on some junkyards over the next year! But for now, I think it is officially safe to say you can absolutely do this project for cheap. I went over the $100 dollar mark due to some mistakes along the way, but adding up the total cost if I got everything right on the first try it'd have been pretty well under. Not bad!

 

I think I figured out the problem! I am right on the cusp of being able to provide the amps drawn by the solenoids to reliably actuate. So, I am going to use 2 relays instead. I really tried to avoid this because it is just more added time involved in the already long shift time, albeit relays are pretty quick (relatively speaking). I will just grab a couple of fused relays and throw them in and the set up should be more consistent/ reliable. Everything seems to be working though, very stoked!

 

That's awesome, man — excited to see how everything comes together for you! Sorry to hear about your family member; sending good thoughts and hoping for a quick and full recovery.

 

New 5V relays are in and working! Was able to take it for a bunch of drives without any CEL coming on, in auto and manual. I do think there is still some electrical safeguard the arduino is doing... it is shutting off and resetting itself on certain shifts (just in manual) so I think there is some surge happening every now and then for shifts...maybe the relays are causing it in certain conditions. So I will keep looking into that, but I have driven a combined 5 or so hours over the weekend with a combo of auto and manual and only experienced the arduino reset twice, in which case it just goes back to auto. Not 100% satisfied yet, but I consider that a very successful test run! I will keep poking around with improvements to make it as reliable as possible, but I dont imagine there will be too many more updates other than maybe some cleanup and troubleshooting the voltage spike.

I am in the process of rebuilding a rotrex unit, so in Spring 2026 when I install that, I will put in a new shift light and gear indicator pod, as well as a corolla iM steering wheel. Those are just about the only remaining items for the future! (Unless something blows up!) Thanks for all the support and everyone who followed along!! Been a really fun and challenging project! If we ever become able to upload videos to this site, i'd love to include a few. Seems like we can only attach links.

 

Figured out the occasional freeze-up. When a gear is called with both relays on at once, every once and a while they will draw too much current. I put a 50 ms delay in between toggling those both high for upshifts and the issue has not happened since! Truck is fully back together. Again, may mess around with some code optimizations to make things a bit quicker, but now I am satisfied with the project as a whole. On to the next project!!