Attempting a Chrysler 41TE Trans Control With Microsquirt

'Microsquirt' Transmission Control development and support.

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SRT4VAN
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Attempting a Chrysler 41TE Trans Control With Microsquirt

Post by SRT4VAN »

I'm attempting to get a 41TE trans to work with Microsquirt. My 2.4 SRT4 engine is being controlled with MS3 w/MS3X V3.57. I'm using a borrowed Microsquirt V1 or V2 (I believe it's a V1) to control the 41TE. In the Microsquirt trans control manual it has a wiring diagram for V3. In the supplement manual it has a wiring diagram for versions 1 & 2. I'm using the later.

My problem, I have it all wired up, Key On Engine Off I run through the gears via the gear sector. It's not indicating what I think it ought to be indicating, and on a couple of selections I'm getting a red "set fault" indicator at the bottom of the screen. Under "Trans controller setup" there is a "Gear Position." It's analogue gear position and is asking for voltage but the Chrysler 41TE is digital (four wires that are either ground or open depending on selection). There is no place for me to choose digital. Can anybody help me with this?

Also I don't know how to post pictures. I'd like to to be able to explain myself a little better so if somebody can at least explain that to me I can edit this post with pictures to help clarify what I'm asking. Thanks.
slyrye
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Re: Attempting a Chrysler 41TE Trans Control With Microsquir

Post by slyrye »

Use MegaShift with MSGPIO, im using it on my Chrysler Viyager 3.3 just be careful with some dropdown menus in TunerStudio like VSS it's finicky..! edit it in offline mode..! it could be a TuneStudio issue..!
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nathaninwa
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Re: Attempting a Chrysler 41TE Trans Control With Microsquir

Post by nathaninwa »

Maybe it's possible the engine needs to be running for gear position to display correctly
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Matt Cramer
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Re: Attempting a Chrysler 41TE Trans Control With Microsquir

Post by Matt Cramer »

Exactly what is this transmission out of? It is possible that, like Ford's 4R70W, they made some variants with analog and some with digital shift position inputs.
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jsmcortina
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Re: Attempting a Chrysler 41TE Trans Control With Microsquir

Post by jsmcortina »

slyrye wrote:Use MegaShift with MSGPIO, im using it on my Chrysler Viyager 3.3 just be careful with some dropdown menus in TunerStudio like VSS it's finicky..! edit it in offline mode..! it could be a TuneStudio issue..!
Have you got the 41TE to work ok?
A number of years back I did some development work on the Microsquirt code with "Unaclocker" testing on his 41TE. It proved too difficult for both of us.

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guhfluh
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Re: Attempting a Chrysler 41TE Trans Control With Microsquir

Post by guhfluh »

jsmcortina wrote:
slyrye wrote:Use MegaShift with MSGPIO, im using it on my Chrysler Viyager 3.3 just be careful with some dropdown menus in TunerStudio like VSS it's finicky..! edit it in offline mode..! it could be a TuneStudio issue..!
Have you got the 41TE to work ok?
A number of years back I did some development work on the Microsquirt code with "Unaclocker" testing on his 41TE. It proved too difficult for both of us.

James
I'm way out of the loop on current MS happenings, but what I've looked at recently seems like the Microsquirt Transmission code has the needed solenoid delay timing strategy to tune/control the 41te and other clutch to clutch transmissions, where the GPIO/MegaShift code does not. According to Una's old posts, he was using a GPIO, but spoke about using your/James' code. I'm not sure how that works, but I thought the GPIO setup could only use the MegaShift code and not the current Micro Trans code?

Anyway, I'm interested in seeing what might be needed to run the 41TE or variants and further refine the code if needed. I have a MS2 in my car, but it's v2.2 main board and may also not have CAN, but I'll have to check. I'm having trouble getting parts for my current transmission, so I'm interested in swapping in a 41TE. Unfortunately I just gave away the 41te I had, so I'll have to grab another. Haha.
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apalrd
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Re: Attempting a Chrysler 41TE Trans Control With Microsquir

Post by apalrd »

I'm not an MS Trans user either, but I have some insight on the 41TE and derivatives 'native' control method.

Most/All transmissions MS Trans works with rely on adjusting line pressure to smooth the shift, and use overrunning clutches so only a single clutch is in control of the shift. The 41TE and all later clutch to clutch transmissions do not drop line pressure during the shift, and they rely on software to execute shifts correctly at full pressure with no overrunning clutches.

For the Chrysler transmissions, the clutches are duty cycle controlled during the shift to control clutch pressures. Newer clutch to clutch transmissions use VFS solenoids which are current controlled instead of duty cycle controlled but the principle is similar. Duty cycle control is required because of differences between accumulators and clutch volumes, so simply firing the solenoids with a time offset will result in overlap or underlap at some portions of the shift (since the clutches don't fill and drain at the same rates). Also, during the speed phase of the shift, the clutch will lock too rapidly and this will result in a big torque bump. The Chrysler transmissions usually only control one solenoid with duty cycle control, and try to match the mechanical rate of the other solenoid (which is just fired on or off). Newer transmissions will duty cycle or VFS pressure control both clutches to hit a calibrated ramp rate. If you want more info, let me know.
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Re: Attempting a Chrysler 41TE Trans Control With Microsquir

Post by slyrye »

The 41TE Tranny that I have has a full mechanical limp mode operation, It doesn't need the stock tranny ecu to downshift or upshift until second gear, I only have to make a logical control of the 3rd and OD shift solenoids
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apalrd
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Re: Attempting a Chrysler 41TE Trans Control With Microsquir

Post by apalrd »

slyrye wrote:The 41TE Tranny that I have has a full mechanical limp mode operation, It doesn't need the stock tranny ecu to downshift or upshift until second gear, I only have to make a logical control of the 3rd and OD shift solenoids
Are you sure it's a 41TE?

The 41TE and family will default to second gear only if the ECU isn't powered. There is also no '3rd' shift solenoid. There are 5 clutches (R, UD, OD, LR, and 24) with R being driven directly from the shift lever and the rest each having a dedicated solenoid (LR shares with the torque converter clutch). To get 2nd gear by default, UD and 24 are default applied (so energizing the solenoid releases the clutch), and OD and LR are default released (energizing the solenoid applies the clutch). You also can't reverse without ECU control because reverse needs the R and LR clutches and LR defaults to released. So, it very much needs some ECU to shift anywhere but second.
slyrye
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Re: Attempting a Chrysler 41TE Trans Control With Microsquir

Post by slyrye »

That is really weird.. I'll post videos later on...! we might be into something worth digging...! 41TE is a real pain controlling..! :D and may I remind you that the A604 transmission solenoid pack is waiting for 12volts or sourcing to activate...!
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