Kwebb9 Posted October 12, 2016 Share Posted October 12, 2016 So my 91 Big Ton 2wd has the power/comfort switch for the trans and it works perfectly. What I'm wondering is does that switch control the TCM or the actual solenoids in the valvebody because I want to convert to 4WD. Also, electrical wise, how much is different between a 91 AW4 and let's say a 97 and up AW4? Thanks! Link to comment Share on other sites More sharing options...
MeanLemons Posted October 12, 2016 Share Posted October 12, 2016 87-90 aw4 interchange. 91-96 aw4 interchange. 97 is a standalone year but can be adapted to work in 91-96. 98-01 interchange. http://www.naxja.org/forum/showthread.php?t=1053970 Link to comment Share on other sites More sharing options...
cruiser54 Posted October 12, 2016 Share Posted October 12, 2016 The switch just switches the TCU to a different shift program. the factory eliminated it in late 91 and left it in Power mode. Here's how I deal with it.: http://cruiser54.com/?p=435 Link to comment Share on other sites More sharing options...
Minuit Posted October 12, 2016 Share Posted October 12, 2016 If you swap to a later transmission but keep the original TCU will you still be able to change shift modes? Sent from my LG-D850 using Tapatalk Link to comment Share on other sites More sharing options...
cruiser54 Posted October 12, 2016 Share Posted October 12, 2016 If you swap to a later transmission but keep the original TCU will you still be able to change shift modes? Sent from my LG-D850 using Tapatalk I don't know. I would not keep that switch in anything. Link to comment Share on other sites More sharing options...
Zebvance Posted October 12, 2016 Share Posted October 12, 2016 If you swap to a later transmission but keep the original TCU will you still be able to change shift modes? Sent from my LG-D850 using Tapatalk I don't know. I would not keep that switch in anything. I actually like mine. My mj with its wore out engine, over sized tires and not correct gearing behaves better on the highway in the comfort vs the power setting. Seems like its not shifting into OD as much, even though it is still struggling to stay in it regardless... Link to comment Share on other sites More sharing options...
Kwebb9 Posted October 12, 2016 Author Share Posted October 12, 2016 Would a AW4 with a 242 off the back have the same output shaft length and spline count as a 231? Out of a 93 XJ Link to comment Share on other sites More sharing options...
HOrnbrod Posted October 12, 2016 Share Posted October 12, 2016 So my 91 Big Ton 2wd has the power/comfort switch for the trans and it works perfectly. What I'm wondering is does that switch control the TCM or the actual solenoids in the valvebody because I want to convert to 4WD. Also, electrical wise, how much is different between a 91 AW4 and let's say a 97 and up AW4? Thanks! The P/C switch applies a ground signal to TCU pin C11 in the POWER position. I haven't traced it out any further since I hard-wired that switch permanently to the POWER position a long time ago. Link to comment Share on other sites More sharing options...
omega_rugal Posted October 12, 2016 Share Posted October 12, 2016 The P/C switch applies a ground signal to TCU pin C11 in the POWER position. I haven't traced it out any further since I hard-wired that switch permanently to the POWER position a long time ago. mmm how about turning that feature into a auto/manual? switch.. interesting... Link to comment Share on other sites More sharing options...
gogmorgo Posted October 12, 2016 Share Posted October 12, 2016 I think you could toss a relay into the fused line for the TCU, which would turn the TCU on or off, allowing you to shift with the gear lever. Assuming pulling the trans fuse has the same effect as unplugging the TCU. I'm actually tempted to try this out now. Got no use for the "comfort" setting, just makes me think there's something wrong with the truck whenever I bump it. Link to comment Share on other sites More sharing options...
cruiser54 Posted October 12, 2016 Share Posted October 12, 2016 So my 91 Big Ton 2wd has the power/comfort switch for the trans and it works perfectly. What I'm wondering is does that switch control the TCM or the actual solenoids in the valvebody because I want to convert to 4WD. Also, electrical wise, how much is different between a 91 AW4 and let's say a 97 and up AW4? Thanks! The P/C switch applies a ground signal to TCU pin C11 in the POWER position. I haven't traced it out any further since I hard-wired that switch permanently to the POWER position a long time ago. Renix supplies voltage to C11 of the TCU in the Power mode. Therefore, if your 7.5 amp "trans" fuse is blown, you will be stuck in comfort mode and have no reverse lights. Link to comment Share on other sites More sharing options...
cruiser54 Posted October 12, 2016 Share Posted October 12, 2016 I think you could toss a relay into the fused line for the TCU, which would turn the TCU on or off, allowing you to shift with the gear lever. Assuming pulling the trans fuse has the same effect as unplugging the TCU. I'm actually tempted to try this out now. Got no use for the "comfort" setting, just makes me think there's something wrong with the truck whenever I bump it. It will shift 1,3,4 if you do that. Link to comment Share on other sites More sharing options...
Eagle Posted October 12, 2016 Share Posted October 12, 2016 I think you could toss a relay into the fused line for the TCU, which would turn the TCU on or off, allowing you to shift with the gear lever. Assuming pulling the trans fuse has the same effect as unplugging the TCU. I'm actually tempted to try this out now. Got no use for the "comfort" setting, just makes me think there's something wrong with the truck whenever I bump it. Pulling the fuse for the TCU is one of the diagnostic procedures outlined in the FSM for the AW4. I believe when shifted manually and the TCU is disconnected there is no second gear (or maybe there's no first gear). You would also need a toggle switch to control torque converter lockup. Many, many years ago, on whatever the predecessor forum was to NAXJA, there was a retired AMC engineer named Frank Sweigert who had put an AW4 in a Hornet (IIRC) station wagon. He went the other route -- he used a TCU and he controlled it entirely electrically, using a six-position rotary switch. Link to comment Share on other sites More sharing options...
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