kazzx Posted January 18, 2007 Share Posted January 18, 2007 I just purchased a 1987 MJ and there is a switch on the dash that says "comfort" and "power" what is this? I don't feel like using the search. Link to comment Share on other sites More sharing options...
87manche Posted January 18, 2007 Share Posted January 18, 2007 changes the shift behavior of the AW4 trans. most leave it in power for firmer shifts. Link to comment Share on other sites More sharing options...
Oizarod115 Posted January 18, 2007 Share Posted January 18, 2007 changes the shift behavior of the AW4 trans.most leave it in power for firmer shifts. gas mileage is better in comfort. seems to be alot better, like 2-3mpg better. but power does have a more firm shift. Link to comment Share on other sites More sharing options...
Eagle Posted January 19, 2007 Share Posted January 19, 2007 changes the shift behavior of the AW4 trans.most leave it in power for firmer shifts. gas mileage is better in comfort. seems to be alot better, like 2-3mpg better. but power does have a more firm shift. Something is wrong. "Comfort" allows the trans to slip more. Fuel economy should be perceptably better with it set to "Power." The transmission also lasts longer when it's set to Power. Link to comment Share on other sites More sharing options...
Oizarod115 Posted January 19, 2007 Share Posted January 19, 2007 it just shifts earlier not necessarily any more slip, just revvs lower. i know the jeeps without the switch always have worse mileage. but i suppose that could be an HO thing? i know moms (MOMs, not a racecar driving mom, a normal mom driver) XJ 2wd stock auto 4.0 pulls ~15mpg TOPS whereas my brothers XJ on 33s with 3.55s never got under 17-18 range. and now its killer with 35s and 4.88s Link to comment Share on other sites More sharing options...
Red Dog Posted January 19, 2007 Share Posted January 19, 2007 Comfort Setting is for highway driving, shifts sooner with out excessive RPM required to change gears. Saves Gas. Power holds the tranny in low gear longer to deliver more torque for pulling in low gear. Works the same as when you "Punch It" to shift the tranny in low, or passing gear, to deliver more tourqe at a higher engine RPM. :driving: Red Dog Link to comment Share on other sites More sharing options...
DirtyComanche Posted January 19, 2007 Share Posted January 19, 2007 They did away with the switch. Went perma-power. Mmm, 1990? Or was it when they brought in the HO. My 89 XJ has it. I always leave it in power. Doesn't make much difference, other than it feels more like a slush-box in comfort and I HATE slush boxes. Anyways, the HoHo gets worse milage because there's no nock sensor so the timing follows a fixed curve. Which is retarded. Link to comment Share on other sites More sharing options...
Eagle Posted January 19, 2007 Share Posted January 19, 2007 it just shifts earlier not necessarily any more slip, just revvs lower. No, it also "softens" the shifts by allowing the torque converter to slip more. This creates more heat, and heat shortens the life of the converter. Anyways, the HoHo gets worse milage because there's no nock sensor so the timing follows a fixed curve. Which is retarded. Correct. Link to comment Share on other sites More sharing options...
Oizarod115 Posted January 19, 2007 Share Posted January 19, 2007 yeah, 1990s had the switch so the change must've been with the HO I'm a biiig fan of manual on the street, (love mine) but I'm going slushbox for all kinds of wheeling reasons. didnt know that the switch changed the actual converter "settings" for lack of a better phrase, interesting to know, tim won't care though, his B&M cooler keeps it nice and cool Link to comment Share on other sites More sharing options...
BrettM Posted January 19, 2007 Share Posted January 19, 2007 No, it also "softens" the shifts by allowing the torque converter to slip more. This creates more heat, and heat shortens the life of the converter. Eagle, I respect your Jeep knowledge very much, but I'm going to have to call BS on this one. The transmission has no electrical input to determine how much the torque convertor slips, and therefore changing the electronics in the TCM combined with the power/comfort switch can not do this directly. Indirectly, the convertor does slip more because in comfort mode all the shift points occur before the stall speed of the torque convertor. Heat does not damage the convertor unless it is excessive heat. We know it's bad to run the 4.0 at 250 degrees, but you could use that same argument to say we should all install huge radiators and 160* thermostats to try and make the 4.0 run at 160*, which would not be beneficial. With reasonable driving, or with agressive driving and a good tranny cooler, the comfort switch will not indirectly create enough heat to damage the transmission or torque convertor. It has been my experience as well that I get a few more city MPG when using the comfort mode. Link to comment Share on other sites More sharing options...
HOrnbrod Posted January 19, 2007 Share Posted January 19, 2007 It has been my experience as well that I get a few more city MPG when using the comfort mode. My 91 is an HO and I still have the Power/Comfort switch. I think they were gone in 1992. Much crisper shifting in the Power mode, and gas mileage is about 2 MPG better. I leave it there. Link to comment Share on other sites More sharing options...
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