Engine/Transmission (1994 - 1998) 47RE Questions

[Morphious]

Ok, I'm a standard guy, so I know all about clutches and shifting manuals, etc. . but the mud race truck I'm building is an auto with a 47re out of a 96 12 valve. I'm shedding all the weight I can on the truck and will be eventually rebuilding the transmission with goerend parts that dave and I have figured out will work, including a manual valve body, converter, etc. . , but until I can come up with that denero, I'll be running it as is.



My question is, I will be putting a floor shifter in the truck and manually shifting it through the gears, do I need the pcm at all? Can I wire up a switch for lockup that will lock the converter up in 2nd and unlock at deceleration or some other trigger mechanism? Can I wire up a switch to get it into overdrive?



Morphious

 

[SFPADGETT]

you should be able to wire a switch for each function, but not sure about the "auto unlock" part.



The following locations are from the black 8 pin plug that is mounted in the transmission, (the black plug coming from the throttle body)



TCC pin # 7 (20 gauge orange wire with black tracer)--switch to ground

OD pin # 6 (20 gauge brown wire)--switch to ground

This is assuming that you still have voltage coming in on pin # 1 from the Tran control relay (18 gauge red wire) if not, then you would need to supply voltage to this pin



you will still need the PCM in place to control the various other functions of the truck, but you can wire around it to take manual control of the TCC and OD of the transmission.





alot of people use a 1970 series "head light dimmer, floor mounted switch" for the TCC lockup, you will have to unlock it when coming to a stop, otherwise it is like a stopping your manual truck without pushing in the clutch



since this is a "mud race" truck, you could also use a second floor mounted switch to contol the OD function as well



A factory service manual would be a big help in showing what is controled by the PCM and what other parts you might want to remove.



See pages 8W-31-1 thru 8W-31-7 for the electrical function of the transmission



Geno's is the place to get it, either book or CD.

 

[Morphious]

I've got a FSM, will look at it tonight to see if I need anything else that the PCM controls.



Can you hit the lockup switch immediately after taking off or do I need to wait till I hit a certain gear?



Is the trans control relay fed from the PCM or somewhere different?



What does the "auto unlock" part do?





Morphious

 

[fest3er]

I've got a FSM, will look at it tonight to see if I need anything else that the PCM controls.



Can you hit the lockup switch immediately after taking off or do I need to wait till I hit a certain gear?



Is the trans control relay fed from the PCM or somewhere different?



What does the "auto unlock" part do?





Morphious

Lockup right after launch depends on the valve body. If you want to lockup up 'on launch', make sure you get a VB that lets you do that.



The PCM appears to control the trans relay.



The PCM supplies +5VDC to the solenoid assembly.



The PCM controls the governor pressure.



I would expect the auto-unlock unlocks the TC when you hit the brake. I'm thinking a circuit like the mirror/rear window melters, where a momentary contact switch turns it on or off, and cutting power also turns it off. Depending on how rough mudding gets, you could use a momentary contact foot switch (dead man's switch) to lock up the TC. You get to bouncing too much and your foot slips off, TC is unlocked.

 

[JMcCoy]

I have an ATS Commander, that will lock up the converter at a pre determined MPH. I believe it will lock up as low as 9 mph. I have been happy with the unit. It costs $425. 00 new. I believe other companies out there make similar products. Though it may take a little more effort to opperate, if you can make it happen for the cost of a high beam switch, that would be sweet.

 

[SFPADGETT]

Using the "dimmer switch" , it can be used to lock / unlock the converter at what ever speed you desire (as long as the VB allows, TRANSGO comes to mind), and at a very low cost.

The dimmer switch is a "latching" type--one push to activate, next push de-activates. It will hold the circuit it what ever postition the switch is in.

The advantage of the dimmer switch--low cost, almost bullet proof, reliable, simple--low tech idea that actually works



The "dead man" switch is a great idea for the rough stuff and might help prevent an accident if you were to lose control--it could be used to shut down the engine, or just unlock the converter