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RADesigns Rail Shifter for the AW-4

The Epic Saga of AW-4 Control...
RADesigns Products LLC Rail Shifter Install
by Tim Doumit - March 17, 2011

A couple of years ago I followed my pal Stu Olson into the dark side where they issued gold toes for those who dare to go where no TJ owner had before... The XJ AW-4 Swap.

It's not really dark there, kind of silvery and wiry with some red fluidy stuff and other dirty stuff that somehow always gets in your eyes even though you always wear safety glasses...

Stu was kind enough to put my AW-4 write-up with his on his wonderful jeep site. Mine was written to be used in conjunction with Stu's and should be viewed likewise.  That is... if you choose to follow along with what I have done.

Anyways, after I installed the AW-4, the first thing that I should have done was install some sort of manual control.  This is important for the off-road community, at least the part that does not like how the AW-4 shifts into second gear at exactly at the wrong point creating tension, screaming and uncontrollable urination of Jeep occupants (except driver of course).  If there was one downfall to the AW-4's existence it would be the 2-1 location on the shifter.

Here is the remedy.

AWShifter was still available for a short time during my AW-4 swap. Within a month of this time it was no longer possible to buy one.  Two years later, I was reminded that there was another type of manual shifter available from RADesigns Products LLC.  Actually they have a couple different models for the AW-4 type transmission.

The rail shifter can stand alone without a TCU. From what I understand about the AW-4, the older years are easier to adapt to a TCU/Rail Shifter type control.  Newer years use a different TCU.


This is the Rail Shifter. The black ball is about 1" diameter. There are three wires coming out of the shifter. Blue wire goes to the #1 solenoid, Yellow to the #2 solenoid and the red wire to a keyed 12 volt source which is of course shall be fused.



To direct the TCU (transmission control unit) or the Rail Shifter's control to the AW-4 transmission you need a switch.  At the time of the install I also installed another switch that is pictured in my hand to control the torque converter solenoid.  And, it would be undignified if any electrical modification to a jeep was done without adding more indicator lights to the dashboard area to confuse your loved ones.

Let's start with the Rail Shifter / TCU control switch: I like Pollak Switches.  For this application I used Pollak # 34-359 on/on rocker switch.  The reason that I use Pollak switches is very important to me; they are made in the United States of America (and they seem to be of high quality).

Back to the switches... Let us call it the "Control Switch'.

The control switch comes with the words "MAIN" and "AUX" stenciled on them.  My choice was to use MAIN for normal operations, using the TCU to control the AW-4 and AUX for the times when I want to use the Rail Shifter.

Indicator lights: I used Pico brand indicators, BLUE for solenoid#1 and GREEN for solenoid #2.  These are located in between the Control switch (right) and the Torque Converter lock-up switch on the left. The indicators are not LEDs, however they are very intense.  Fortunately they are installed below eye level in the Age old "dual switch panel modification" that has been chronicled many times all over the internet.  If you do the panel mod, I suggest finding a few good write-ups first and a Dremel tool.

While driving the indicators function as followed:
1st gear - GREEN
2nd gear - GREEN/BLUE
3rd gear - BLUE
4th gear - NONE

The Torque Converter Lock-up Switch: Also made in the U.S.A. It is an on/off/on switch made by Cole Hersee Co. or CH (I do not have a part number for this switch).  It is illuminated with RED or AMBER windows. Looking back, I would have used a plain black rocker instead of this illuminated switch as the angle of view is incorrect plus, in order to make the lights work correctly relays were needed. Relays are never a bad idea.  I always use CH relays part# (RA-400112-DN)

The Torque Converter Lock-up switch functions as follows:
Top position - Normal operations
Middle position - Off
Bottom position - Lock-up

From what I understand, the torque converter lock-up should be used mostly on the street and never in lower gear ranges.  It can add mileage to your gas consumption and help your transmission stay cooler while helping with engine braking.  Maybe Stu will comment here :o)

<Stu's comments>  In my opinion, you should not lock the torque converter off-road.  When I was doing my install, I spoke with a tranny mechanic.  He informed me that the torque converter clutch pack is very small and can not handle the torque found in those lower gears when off-roading.  In fact, if you think about it, an auto tranny will unlock the torque converter when the vehicle gets on a steep uphill stretch of highway.  It does this to save the clutches and to help prevent the engine from bogging down.  Once back on a level stretch of road, the computer locks the converter to reduce slippage (this equates to heat loss) and improve mileage.  </ Stu's comments>

Both rocker switches with the tops depressed is "normal operation mode".


Above is something I worked out after drawing descriptions of what should "work".  I found that there were many who wanted to lend a hand on wiring help but every time something was left out to confuse or baffle me.  Stu offered some very useful tips.  mrblaine suggested putting it all down on paper (we were on another subject at the time).  tjeeper described what he did.  RADesigns instructions were worded sort of funny and the diagrams did not load properly for me until I emailed .jpegs of them to my work and blew them up.  Still, his diagrams need more work.  All contributions were of help.

The Transmission leads plug into the center pins. TCU go on one end. Rail Shifter on the other. Even a caveman could do it... Although it took this troglodyte a while to club his way through it.

On the Torque converter lock-up, I show a indicator light which is not installed.  This may come later as I think it would be useful to have a reminder of what is going on at any certain time.


Ordinarily I will buy unshielded connectors to go onto the switches I install.  I will pull off the little blue plastic collar, pierce/crimp the connector, solder it and heat shrink it with Phillips water tight version. OCD... I know...

This time I decided to just go with shielded connectors behind the switches which meant tinning the ends of each wire. Why do I do this? Look at the last paragraph...  And, it keeps the connector from slipping off the wire by creating a firm place to crimp to.  This is important if you would like to remove the wires from the switch as these switches sort of lock onto the connectors better than anything made in China that you will find in a aisle at the chain auto parts store.

More RADesigns Rail Shifter



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