Chrysler 47RE info

A forum for discussing applications and implementations of the MegaShift transmission controller code for the GPIO from B&G. This can control up to 8-speeds and 6 shift solenoids (plus a 16x9 table for controlling a PWM line pressure valve). It has manual and fully automatic modes (16x9 load x speed table), with under and over rev-limit protection, and full data logging of all inputs and outputs (among many other abilities). A TransStim to test your completed board is also available.
ntstlgl1970
Posts: 11
Joined: Sun Dec 07, 2008 6:39 pm

Chrysler 47RE info

Post by ntstlgl1970 »

Hi,

I'm building a 1999 47RE (rwd) trans for my 70 Barracuda that I would like to control. The engine (440) is setup with MS-II/EDIS and a wideband. I have some good (and what I hope is enough) info on the electronic control system.

It has:

Trans fluid temp sensor
Governor pressure sensor
Governor pressure solenoid
O/D (3-4) Shift Solenoid
TCC Solenoid
Output Speed Sensor
And a Park/Neutral Switch.

Some of the function info I've found: (from chrysler training material and service info)

The governor pressure sensor measures output pressure of the governor pressure
solenoid valve. This feedback is needed by the PCM to accurately control pressure.
The unit is an absolute pressure device and the output is calibrated to be .35 to .65
volts at 14.7 psi (normal barometric pressure). Since this is an absolute pressure
device, 0 psi calibration is required often to compensate for changing atmospheric
pressure or altitude. This voltage measured at 0 psi is referred to as zero pressure
offset.

Governor pressure should be no more than 3 psi at curb idle speed and wheels not
rotating. If pressure exceeds 3 psi, a fault exists in the governor pressure control
system. Governor pressure under acceleration should increase proportional to
vehicle speed. Approximately 1 psi for every 1 mph.

The (governor pressure) solenoid valve regulates line pressure to produce governor pressure. The average
current supplied to the solenoid valve controls governor pressure. One amp current
produces zero psi governor pressure. Zero amps sets the maximum governor
pressure. Current is regulated by modulation of the pulse width of a 512 hz driver
frequency (512 cycles per second).

The purpose of the transmission temperature sensor is to provide transmission fluid
temperature information to the PCM. The PCM uses this information to control
engagement of the fourth gear overdrive clutch, the converter clutch, and governor
pressure. The normal resistance value for the thermistor at room temperature is
approximately 1000 ohms for transmissions built prior to the 2002 model year. The
resistance value for late model transmissions has been increased to 2000 ohms. The
thermistor is part of the governor pressure assembly and is immersed in
transmission fluid at all times (fig. 60). It is a negative temperature coefficient
thermistor.

I am in the process of setting up this combo on a stand where I can run the engine and transmission. I have a lab scope, DVOM that reads Hz and extra time at my disposal. If there is anything I could contribute to help further the project along or if you are in need of any additional beta testers, please let me know.

Thanks!
Eric
Bernard Fife
Posts: 1696
Joined: Fri Apr 04, 2008 1:28 pm

Re: Chrysler 47RE info

Post by Bernard Fife »

Eric,

This looks similar to the GM 4L60E at first glance. The 4L60E is the 'default' application for the MShift code/hardware. So there are no obvious barriers to controlling it, but we need more info to be sure.

To know if we can control the 47RE, in addition to the pressure control strategy, we need to know what inputs it has for the shift lever position, and what solenoids are activated to change to each gear (unless it has none, and the shift is determined by the governor pressure alone).

We also need to know the DC resistance and as many PWM parameters as may be applied in the trans. (at each solenoid). The 512 Hz you note is useful, and can already be done in the code (or very near to it). For the NTC temperature sensor, we need the resistance at three widely spaced temperatures (32F, 72F, and 212F, for example), because the output is a curve. For an example of the sort of info we need, see the thread here: viewtopic.php?f=4&t=24

The pressure sensor and solenoid shouldn't be a problem, these are already in the code (though not linked to each other at this point).

The more info we have (and that you can dig up) the better!

Lance.
"Never wrestle with pigs. You both get dirty and the pig likes it." - George Bernard Shaw
ntstlgl1970
Posts: 11
Joined: Sun Dec 07, 2008 6:39 pm

Re: Chrysler 47RE info

Post by ntstlgl1970 »

Lance,

I read through the 41TE thread, that is an all electronically controlled trans. Mine is pretty much a hydraulic 3 speed 727 (1-2 and 2-3 controlled by the springs/valves in the valve body only) with an overdrive hung on the back. The governor has control over where the 1-2 and 2-3 shifts occur but not the 3-4 or converter lock up. The 3-4 and TCC solenoids are just on-off. The neutral safety switch has no "gear" inputs to the ECM, just the Park/Neutral and Reverse positions for backup lamps and grounding the coil for the starter relay.

What I think I need is to be able to reference VSS and trans temp to create a pressure required "curve" for the governor solenoid and use the governor pressure transducer to close the loop or use as reference to get the curve "right". Then use the RPM/MAP/CTS inputs from MS-II along with the VSS to calculate when to ground the TCC and 3-4 Solenoids

Here are some other specs that I have dug up, still looking for the temp to resistance/voltage specs for the trans fluid temp sensor. I may just make some measurements myself since chrysler doesn't like to publish sensor specs even in their code testing.

Temp sensor Signal range is 4.5-1.0 V
Gov. Sol. Control @ 1 amp for zero psi (so 1A @ 512hz)
B25 Dr Blue/Black OSS Ground 0.0 V
B28 Lt Grn/Black OSS Signal @ 3.0 VAC at 30 mph
B29 Lt. Grn/White Governor Pressure Sensor .60-.66 V at zero psi
3.0 V at 60 psi
4.5 V at 110 psi
Lock-up and OD On/Off Solenoids: 31 Ohm
Governor Solenoid Linear 3 Ohm

I'll see what else I can find...
Eric
Bernard Fife
Posts: 1696
Joined: Fri Apr 04, 2008 1:28 pm

Re: Chrysler 47RE info

Post by Bernard Fife »

Eric,

Okay, this is good info, and looks 'do-able'.

In the code there is already a 12x12 (mphxload) line pressure PWM table which should work for your application. There is also a line pressure sensor input that can be used for the governor pressure sensor. Do these need to be linked by some closed-loop logic/code, or would you do the calibrating manually (i.e., look at the shift speed and line pressure, then adjust the 12x12 PWM table to bring the shift to where you want it to be)? If you are tuning 'manually', the existing code ought to work. Puting some code in isn't hard wither though (depending on how sophisticated it needs to be!).

The TCC function ought to work as is. The 3-4 solenoid could be run be either the 12x12 shift table or a spare output, so I think we have that covered. The VSS/OSS ought to work too.

The electrical characteristics all look okay so far too.

Any info you dig up is useful, and I will think about what we might need to change in the code to accomodate this trans and you can let me know about what the link between the pressure solenoid PWM and the pressure sensor should look like.

Lance.
"Never wrestle with pigs. You both get dirty and the pig likes it." - George Bernard Shaw
ntstlgl1970
Posts: 11
Joined: Sun Dec 07, 2008 6:39 pm

Re: Chrysler 47RE info

Post by ntstlgl1970 »

Lance,

I would tune manually using the 12x12 table. This application still uses a throttle pressure (cable driven) input to increase the MPH of the 1-2 and 2-3 shift on top of the governor pressure. At this point I'm not interested in tying the governor pressure solenoid "command" to the output of the governor pressure sensor in any sort of loop.

Found this on the pressure "curves" created by the pcm:
"The different curves allow the PCM to adjust governor pressure for varying conditions. One curve is used for operation when fluid temperature is at or below -1°C (30°F). A second curve is used when fluid temperature is at or above 0.5°C (31°F) during normal city or highway driving. A third curve is used during wide-open throttle operation. The fourth curve is used when driving with the transfer case (4x4 only) in low range".

The only function the governor pressure sensor would serve (in my application) is to confirm the command parameters are correct - 1 MPH = 1psi governor pressure.

Any other functions in addition to that would be icing on the cake.

Are there any beta boards left or would I need to wait for the next batch? I'm looking forward to driving my car in other gears besides 3rd (failsafe).

Thanks,
Eric

ps- here is a pic of the stand I'm building to test everything while the car is being painted.
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tjabo
Posts: 68
Joined: Mon Jan 12, 2009 10:40 am

Re: Chrysler 47RE info

Post by tjabo »

That's a nice rig! ! !
Turbo Neon, converting to 41te trans sometime?
ntstlgl1970
Posts: 11
Joined: Sun Dec 07, 2008 6:39 pm

Re: Chrysler 47RE info

Post by ntstlgl1970 »

Thanks tjabo, I'm hoping that I can get the engine and trans stuff in the ballpark before the car comes back and do final tuning in the car.
Bernard Fife
Posts: 1696
Joined: Fri Apr 04, 2008 1:28 pm

Re: Chrysler 47RE info

Post by Bernard Fife »

Eric,

There is a 12x12 (speed x load) table that can serve as both the base and WOT curves (up to 12 separate curves, actually). There's also a 10 element table to adjust the line pressure control by temp - adding or subtracting a percentage based on the current trans temp, and I think this can be used to provide the 'cold fluid' curve.

So it looks to me like the current code has many of the parameters you would need (actually more, since we have bigger tables). 4WD might need a bit of code tinkering, I'll have to think about it.

I have a few beta boards left, but only one ampseal connector. It is yours if you PM me with your address and phone number.

Lance.
"Never wrestle with pigs. You both get dirty and the pig likes it." - George Bernard Shaw
black99rt
Posts: 1
Joined: Mon Mar 23, 2009 6:07 pm

Re: Chrysler 47RE info

Post by black99rt »

I have a built 46RE in my dakota R/T that I would eventually like to take over control of. The valve body and control strategy should be very similar to the 47re. I even used some 47 parts in my rebuild. I have a factory service manual for this truck, and some other jeeps that used the 4 series chysler rwd transimssions. If there is anything I could lookup/scan to help, let me know.

Also my father used to own a race transmission shop, and went through chyrsler training as a tech when these transissions were being used, so you all can pick his brain through me if you like.
Bernard Fife
Posts: 1696
Joined: Fri Apr 04, 2008 1:28 pm

Re: Chrysler 47RE info

Post by Bernard Fife »

blck99rt,

Sounds great, we will keep this in mind!

Lance.
"Never wrestle with pigs. You both get dirty and the pig likes it." - George Bernard Shaw
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