Is it possible to make the Aw4 shift on demand

[the_bandit87]

This is just an idea I had while I was thinking about the AW4 transmission, how it was electronically controled, and how solinoids controled its shifting. Would it be possible to rig up a switch to make the solinoids operate when you want them to, so you could almost shift gears manually. I was just thinking of this becaus my AW4 (1987) has the 1-2 (no individual second gear), and l've heard how they don't shift to second till the revs are up pretty high. I probably overlooked somthing and its not possible, but I'd just like to know.

 

[biscuitboy87]

i've read that it is possible...do a search.
also, i have read or seem to have read that the AW4 is not electronic (i.e. controlled by CPU). just your basic old tranny.
2%

 

[CW]

Check out this thread.

http://www.naxja.org/forum/showthread.php?t=16328&highlight=aw4+manual

 

[woody]

I did the mod on my 89 (same AW4 trans and CPU as 87) I ended up with two push-pull switches on the front of the console: one locks/unlocks the torque convertor and the other switches between 1-2 or 3-4 depending where the manual shifter is set.

It's a lot like driving a split-shift 'truck' in regards to the TC lock, but it's nice to be able to do a 4>3 downshift on the road without varying the throttle... same for using 2nd gear off road without 1st, or rowing between as the trail needs.

Look at www.bigoffroad.com in the BigTech... Troy Morris has a great writeup.

 

[the_bandit87]

Hey, thanks for the help woody, but I can't find the write up. What I was thinking of doing is making a master arming switch for it that has to have a key to operate, so that if some one else is driving it, they don't ruin my transmission by keeping it in first or second on the highway, the arming switch would shut off the TCU and turn on my other switches, a little more complex, but better be safe than sorry. The other thing I was thinking of was, making the switch almost like a gated manual shifter, but operating on almost the same lines of a distributer (instead of having a rotor, you have a stick that has power running to it, and when you move it to the first gear position, it contacts a terminal which triggers the solinoids to in the trans to set it for first gear, and second trigger second ect.) I just think this would be a little more like a real manual. It'll be more complex than a rotary switch or some other things, but i have an old Shifter type joystick that is small enough to fit in where the ash tray is, I figure I might be able to modify it to do the job. Thanks for the help.

 

[Lawn Cher']

I believe it was BrettM who makes and sells a manual shift kit for the AW4... contact him. It is a pretty sweet setup from the pics I have seen, replaces the TCU.

 

[the_bandit87]

Ok, I've been doing some thinking (and drawing, lots and lots of drawing) and here's where I am. I found the wiring diagram for the 1989 AW4 thats floating around on this site and used it as my jumping off point. I have an AW4 out of a 90 sitting in my garage and to my knowledge its the same 87-90 (except MAYBE for output shaft spline count), I used the diagram to track down the TCU (I was supprised to find that it was a small sardine can sized thing, I thought it would be the size of a text book like that ECU) any ways I have one big question, what is the resistor pack and brake switch for?? They're at the top of the diagram, wire C10. I heard that computers run off of 5 volts so I figured that might be what the resistor does, but I measured the voltage with the multimeter and it comes out 12 volts, and I got 12 volts out of D16, which I assume to be the main powersource, because it has a fuse and dosn't go anywhere else, it goes from the ignition swithch straight into the TCU. The reason I'm asking this is because I want to know if the solinoids in the trans are 12v or 5v, I'm thinking there 12 volt, but I want to be sure because I don't want to fry them and ruin my spare transmission. I was going to test them with a 12volt battery charger.

 

[the_bandit87]

well I'm starting to get some more things together to make the AW4 shift manual, but I have to get a switch made up, and I think I need some more info. Any thing any one has on the AW4 and its Computer controlled shifting would be a big help.

 

[BrettM]

the solenoids take 12v. I made a manual shifter for mine when I swapped it in place of a 5 speed. PM me with any questions, I don't check this section of the board much.

 

[DrMoab]

All you need to do is run a switch to cut the main power to the TCU. Once you do this the tranny will stay in whatever gear you have the shifter in. So if you have it in D it will start out in fourth. Only problem is you also need to run a switch to turn power to the first gear solonid. Because the shifter only doesn't have a seperate first and second gear.

Here is the link to Bigoffroads tech article on how to do this...Its where I did mine from
Second Gear Please

 

[Brian Felts]

I hear it s a different ballgame w the OBDII AW4s.Can anyone shed some light on this?

 

[crazy4moab]

Hey CW!!!! Get by Colfax very often. My son lives up there. Just moved back from Salt Lake City back in November. Need to stop by and take him for a ride. He misses daddy's Jeep. He's 18 so he may ask to drive. :cheers:

See ya..........Mikey

 

[Bloose]

I hear it s a different ballgame w the OBDII AW4s.Can anyone shed some light on this?

Yes the OBDII AW4's will set the MIL if you try to install switches for locking it in one gear or another. A long time ago I was going to look into making some type of box to keep this from happening. Never looked into it much but my guess is it calculates the gear you in by the input and output speed sensors. Would be very easy to do and would get you to a dealer if the TCU sent the proper signals to shift but the trans didn't responde. The box I would have created would have consisted of a Digital to Digital converter that would have taken the input speed pulsed and converted them to an appropriate output speed pulse to send to the TCU depending on what switch setting you selected and what gear the trans "wanted" to be in. Likely it would be pretty cheap and easy to build once you came up with the proper pulse ratios and proper D to D converter. But I never worked on it. I'm actually surprised no one ever came up with a solution for this.

B-loose