Microsquirt/MS2 based transmission controller

[UnaClocker]

That trans just sucks. The factory computers can't controll it correctly half the time. 4th gear is insanely weak/poorly designed.

[guhfluh]

That trans just sucks. The factory computers can't controll it correctly half the time. 4th gear is insanely weak/poorly designed.

I think it is just you and can't believe you haven't been banned from here yet with that attitude.

[UnaClocker]

I'm the only one who even bothered to try to use this transmission. Had a half dozen all jumping up and down about it, but when push came to shove, I'm the only one that laid down the cash, time, and car to do the testing. Pardon me if I'm a bit bitter about the posers who bailed on the project. I can cite references for the problems with the trans if you think I'm being unfairly critical of this worthless pile of junk.
James did an awesome job of completely rewriting his code to support a very strange and stubborn style of transmission. It's a shame nobody else bothered to try the code out.

[guhfluh]

Nothing about the control strategy is specific to the 41TE and still gets used for Chrysler transmissions built today. Even the 68RFE behind the 800ft/lb Cummins uses the same clutch-to-clutch shift strategy. If the strategy was junk, it wouldn't be used in almost every late model Chrysler transmission.

The A604/41TE,40TE,42LE,42AE,ETC. was used by Chrysler for decades. If it was junk, it would not have lasted so long. Yes, the series has a weaker 4th gear than desired and it is a known weak point. Newer designed 4th gear parts are stronger than the older design because of the known weak point and the need for it to handle more power in heavier vehicles. If it can handle a 500-650whp 2500lb Neon running 10's with a few accidental 4th gear shifts, I'd say it's not that bad of a trans, but I wouldn't recommend using 4th under high power and expecting reliability, just like everyone has for years.

[jsmcortina]

... a few other delay values in the PCS controller made it quite feasible to control the 41te very well, but it was still a lot of work to get everything tuned well...

That is the ticket for controlling Chrysler's clutch-to-clutch electronic transmissions, including the RFE series. PCS no longer offers their controller for the Chrysler transmissions because of the intense tuning and tech support required after each sale. From what I have seen, it is simply the tuning of load vs rpm vs solenoid actuation timing that the MS controllers lack to control these transmissions correctly. It's all about the overlap timing, from what I understand.

If you have the time to help test development on this, it could proceed. It certainly seems to be a difficult transmission to control correctly. The GM boxes such as 4L80E are simple as the hydraulics do the actual selection.

James

[wes kiser]

Is there a place describes what transmission control style the code currently can support? I am converting a friends drag DSM to MS3, and he is also interested in replacing the trans controller. These transmissions are generally known as "W4a33" or "F4a33."

Looks relatively standard, 2 shift solenoids, 1 pressure control, and TCC lockup.

[devojet]

I finally got my hot rod regisered 3 weeks ago running the trans code on a GPIO controlling an A340E Toyota gearbox. It works great.

James,

is it possible to get a copy of your latest version of the trans firmware with the new features discussed in this thread? Also CAN pass though doesn't work on the current version I'm using. ie I cant log or tune the engine MS2 if connected to the GPIO serial port. Has CAN pass through been fixed in the newer version? This would be very usefull for me as I use an LCDash which is connected to the MS2 and it would save me disconnecting the dash everytime I want to tune or datalog.

Cheers,

Daniel.

[jsmcortina]

I need to "dust the code off" and make sure it works nicely with the current MS2/Extra and MS3 code.

Please describe in more detail exactly what you are trying to do and what versions of firmware are on each device.

James

[devojet]

Hi James,

The ini signature is "Trans 00013 " but it should be the latest one you posted on the alpha page, I did make some changes to the firmware to suit my set up though. The MS2 is running version 3.2.1.

What I want to do is connect my laptop to the GPIOboard and be able to tune and log both the MS2 and the GPIO trans. I can tune both if I connect to the MS2 serial port but not the GPIO port.

Thanks

Daniel.

[jsmcortina]

Ah, sounds like the serial/CAN needs more work in the trans code then. Not a quick job, but will be done.

James

[devojet]

That will be great.

Thanks
Daniel.

[Tjabo]

I finally got my hot rod regisered 3 weeks ago running the trans code on a GPIO controlling an A340E Toyota gearbox. It works great.

Daniel,

Congrats on getting your hot rod on the road!

I'm very interested in your project, since the A340E seems to be the same transmission as the AW4 used in Jeep Cherokees and some Grand Cherokees. This opens up different possible project for me since I'm tiring of working on the overly complex and difficult e39 540i/6....

Regarding this trans controller software running your transmission, does it monitor line pressure, and if so, how is that input used in the control strategy?

Thanks, and again congratulations!!!

Thad

[devojet]

The line pressure in my A340E uses a mechanical cable connected to the throttle. It does have something that affects shift speed but It doesn't seen to have much affect. still playing with that part.

[Tjabo]

Thanks for the info!

I can't wait to see some video of your hotrod when you are able to get some!

[skalor]

I've been trying to use this for a 4T80e and I'm having trouble with the gear selector logic. Is there a way to change the gear range switch input logic?