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Electronic Manual Gear Control on 4R70W?

6565 Views 21 Replies 13 Participants Last post by  tbirdtess
Ok, I had a ridiculous idea, but here it goes:

Recently, my tranny's wiring harness was damaged and so for the longest time the car only had 2nd and 3rd gears usable.
Now, since these wires control the solenoids directly, can I rig up some kind of override system that will let me manually engage gears (ie drive around in 4th gear all the time) or am I SOL?

In the most basic of terms,

Using the existing wiring harness, can I make an over-ride system to FORCE the tranny to use a particular gear by using a set of interrupt switches on the wiring harness?

Thanks,
Ghost
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Why not just repair the wiring harness? :confused:

Is first gear otherwise thrashed or is it still a good tranny?
dude, repir the harness.
i cant imagine trying to leave a stoplight from a dead stop in 4th gear.....lol
-_- i already FIXED the harness.

When the tranny harness was damaged, it would only use 2 and 3.

NOW, HERE IS WHAT I AM SAYING.

CAN I MAKE SOME SORT OF INTERRUPT SWITCH TO <b>MANUALLY</b> CONTROL THE GEAR SOLENOIDS? Most likely, by using an interrupt on the wiring harness.
Is that doable or not.

thanks.
ghost

ps.
porky, i am dying to do a 5-speed swap. this car would have huge balls if it could just be a 5-speed.
unfortunately 94-95 5-speed center consoles are quite a rarity and unfortunately, quite costly.
What I want to do is be able to cruise around in 4th gear at 800rpm like I used to.
This motor's got the torque for that.
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you can get a chip tuned to lock the trans in gear.
manual 1 = 1st
manual 2 = 2nd
D w/ od off = 3rd
D w/od on = 4th

no down shifts or up shifts unless you move the gear selecter.
The_Ghost said:
-_-
ps.
porky, i am dying to do a 5-speed swap. this car would have huge balls if it could just be a 5-speed.
unfortunately 94-95 5-speed center consoles are quite a rarity and unfortunately, quite costly.
What I want to do is be able to cruise around in 4th gear at 800rpm like I used to.
This motor's got the torque for that.
sooo.........look at my homepage in my profile. there aren't any center consoles designed to work with a hurst v-matic 2 ratchet shifter but mine seems to.... its just a matter of getting some fiberglass, small pieces of aluminum from lowes, and getting creative
You could get a Baumann TCS controller which allows you to have a full manumatic-style control that turns your cruise control buttons into "paddle shifters." They aren't cheap, but you do get to reprogram shift points, torque converter lockup, and all sorts of good stuff like that when using it as an automatic, with the added bonus of the full manual control.

http://www.baumannengineering.com/tcs.htm
cougar man said:
You could get a Baumann TCS controller which allows you to have a full manumatic-style control that turns your cruise control buttons into "paddle shifters." They aren't cheap, but you do get to reprogram shift points, torque converter lockup, and all sorts of good stuff like that when using it as an automatic, with the added bonus of the full manual control.

http://www.baumannengineering.com/tcs.htm
Yeah, don't do that...

Find me a happy owner of one of those and I will bring you 10 or more that hate it per.

Darrin
Well, yes you could technically control the solenoids with switches, but it would be quite the PITA while driving. Both solenoids off=2nd gear. Both solenoids on=4th gear. Either one or the other on or off make first and third gear.

That said, if your harness is fixed as you say, and the trans still acts like that then it is probably fried and needs a rebuild.
Crap, I just bought the Baumann TCS. I haven't hooked it up and won't for a while as the motor/trans isn't swapped into the BMW yet. Sounds like the solenoids could be easily triggered with microswitches and relays (if required). So for the first gear position on the shifter it could send 12V to the one solenoid. At the 2nd gear position it would be a blank spot with no solenoids triggered. 3rd would be the other solenoid getting 12V thru a microswitch, and 4th gear would have a switch that would energize both solenoids. Sounds easy enough. However, how do you control the line pressure in the trans to increase with throttle angle? Would that just be another wire in the harness that goes to a TPS? I suppose the lockup converter would just be a single wire hooked up to a toggle switch (or microswitch on the throttle that would engage the converter between, say, 1/4 and 3/4 throttle when also the microswitch for 4th gear is in closed circuit).
hotbird said:
Well, yes you could technically control the solenoids with switches, but it would be quite the PITA while driving. Both solenoids off=2nd gear. Both solenoids on=4th gear. Either one or the other on or off make first and third gear.

That said, if your harness is fixed as you say, and the trans still acts like that then it is probably fried and needs a rebuild.

rest assured, my transmission is fully functional now that it's got a working harness.

interesting to know the solenoids work like that... with as many wires as there are in that harness, i figured it had a set of wires for there to be a solenoid for each gear.




about the post earlier--
who makes the tune that will LOCK the trans in whatever gear I tell it to using 1 for 1st, 2 for 2, o/d off for 3, o/d on for 4th gear, and where do I get it?
VicRattlehead said:
you can get a chip tuned to lock the trans in gear.
manual 1 = 1st
manual 2 = 2nd
D w/ od off = 3rd
D w/od on = 4th

no down shifts or up shifts unless you move the gear selecter.

Who does that? The car has an SCT tuner with it already; can an SCT tuner do that?
yep, jerry and i were discussing doing this for my car at one point. i ended up getting a new valve body instead. gonna let the eec do the shifting.
Yes, you can shift manually by using a rotary or pushbutton switch to
ground the appropriate combinations of the 2 shift solenoids. You may
have an unhappy PCM, since the 2 wires from the SSs to the PCM will be
broken when you are using the manual switch.

The PCM may become unhappy when it sees you in 2nd when it is commanding
3rd, for instance. I just don't know how unhappy.

With this sort of manual shift arrangement, there's nothing to prevent you
from dropping into 1st accidentally when flying. If you're lucky it will
snap a U-joint before you lunch the motor. If the drivetrain holds, kindly
send us the pix of the motor internals - we all need the entertainment.

You also have to deal with the lockup clutch solenoid. If you manually control this,
you have to make sure it releases whevever you hit the brakes. Otherwise
you face the scenario where you lockup the brakes, stall the engine and lose
power steering and maybe brake boost while still going fast. Once the tranny pump stops, you're out of business.
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How would that work in a carbed car (something without a computer at all)? It seems to me that a shift lever that grounds the correct solenoid or combination of solenoids when in a certain position would be the best answer to avoid accidentally going into 1st gear at high speed. How do you address the fluid pressure in the trans? Is that not electronically controlled?
Fluid pressure is controlled by a duty-cycled solenoid...
If you can live with a permanent "Check Engine" light....

P07xx (most of them I guess)
P17xx (some of those too)
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