big88chevy Posted September 24, 2009 Share Posted September 24, 2009 I have a huge problem, i started my fall semester and my DD is down for at least 2 months. I bought a 1991 4x4 Comanche 4.0 with what the guy said was a bad trans. I bought an Aw-4 replaced the trans and it doesnt do a damn thing. i cannot figure out what the problem is, I'm not very familiar with jeeps but it doesnt seem like they are that different from anything else. I did not replace the torque converter but if it was bad the truck would at least lunge a little bit or even roll a tiny. There are a few vacuum problems but could that cause the trans to not engage? I tried unplugging the TCU and nothing changed, Please guys i need some help. Link to comment Share on other sites More sharing options...
Geonovast Posted September 24, 2009 Share Posted September 24, 2009 What year is the 'new' trans from? Are you sure the 'new' trans was even good? Link to comment Share on other sites More sharing options...
jpdocdave Posted September 25, 2009 Share Posted September 25, 2009 did you try moving the t case shifter around. problems w/ the aw4 are possible, but rare. i'd look at your t case shifter, and linkages. maybe its in nuetral. Link to comment Share on other sites More sharing options...
big88chevy Posted September 25, 2009 Author Share Posted September 25, 2009 the aw4 is from a grand Cherokee forget what year (i read that it was compatible)and I'm pretty sure its good, ive blown trans' before and this thing doesnt make any noise, doesnt lurch forward when its cold or anything. Thats what i thought about the t-case but i checked and the linkage is set right, i even tried every position. Link to comment Share on other sites More sharing options...
Automan2164 Posted September 25, 2009 Share Posted September 25, 2009 What year grand? Most grans had a 42RE behind the 4.0L. Rob L. Link to comment Share on other sites More sharing options...
Geonovast Posted September 25, 2009 Share Posted September 25, 2009 An AX-15 would solve your problems :thumbsup: Link to comment Share on other sites More sharing options...
HOrnbrod Posted September 25, 2009 Share Posted September 25, 2009 I did not replace the torque converter but if it was bad the truck would at least lunge a little bit or even roll a tiny. I tried unplugging the TCU and nothing changed, Please guys i need some help. You bought a 91 MJ w. a bad trans. Do you know the original symptoms as to why it was bad? Then you changed out the AW4 and it's still bad. I think you should look for something external to the AW4; linkage moving the shifter arm, broken throttle cable, inputs and outputs from the TCU, or even try another TCU to see if it changes things. I have an AW4 manual in .pdf format that describes how to do these checks; shoot me a PM with your email and I'll send it to you. :cheers: Link to comment Share on other sites More sharing options...
Eagle Posted September 25, 2009 Share Posted September 25, 2009 the aw4 is from a grand Cherokee forget what year (i read that it was compatible)and I'm pretty sure its good, ive blown trans' before and this thing doesnt make any noise, doesnt lurch forward when its cold or anything. Thats what i thought about the t-case but i checked and the linkage is set right, i even tried every position. The AW4 was used in the Grand Cherokee only in the 1993 model year. It is possible that you have a torque converter that doesn't match your transmission. On another note, getting back to basics, are you certain the torque converter is actually bolted to the flex plate? I ask this only because I happen to ... ahem ... know a certain person (who shall forever remain unnamed) who replaced a flex plate. A friend came over one night to help put everything back together. Once everything was snugged up, they (yeah, "they") started the engine, put the tranny in gear .. and the rear wheels didn't move. After exhausting all possible problems, the ... unnamed person ... asked his friend if he had tightened the bolts holding the torque converter to the flex plate. "No, I thought you did that." Oops. Link to comment Share on other sites More sharing options...
big88chevy Posted September 25, 2009 Author Share Posted September 25, 2009 i do not know the symptoms of why it was bad, i was told a bad trans and thats it. i got the truck for $200 and I'm a decent mech. so i figured sweet i got a deal. I know the flywheel bolts are all on but i totally didnt think about the torque converter not matching??? Wouldnt it have a different spline pattern? And yes an AX-15 would solve my prob but I'm in NJ and i couldnt find one, if any one is in jersey and wants to sell one let me kno. But anyways, I'm gonna do a little test today to see if the T-case is bad but if its not, I'm back to square one. :wall: Link to comment Share on other sites More sharing options...
mjeff87 Posted September 25, 2009 Share Posted September 25, 2009 another possibility.....your original trans may have been bad, and it could have been a 21 spline output with a matching 21 spline input TC. The ZJ trans is a 23 spline. Your 21 spline TC will bolt up to a 23 spline output tranny, but there's no spline engagement between the two....the output just spins inside the input gear. Had it happen to me swapping an AX5 into a buddy's YJ in place of a TF909. Neither of us ever figured a 909 had a 23 spline output and didn't bother checking, just slid the 21 spline 231 onto it and couldn't figure out why it didn't move. :dunno: Oops... Jeff Link to comment Share on other sites More sharing options...
big88chevy Posted September 25, 2009 Author Share Posted September 25, 2009 crap.. i hope thats not the problem cause that thing was a b*@$£ to take out. Is there any way to tell if its 21 or 23 spline without taking it off, maybe like a stamp or cast number??? Link to comment Share on other sites More sharing options...
aemsee Posted September 25, 2009 Share Posted September 25, 2009 You COULD have a bad converter that doesn't make the trans lurch or jump. The turbine spins the input shaft. The impeller is welded to the case. Only the fluid makes the impellor spin the turbine. You might want to pull a cooler line and fire it up for a minute to make sure the pump is working. No pump, no fluid to converter, trans no worky. Link to comment Share on other sites More sharing options...
big88chevy Posted September 25, 2009 Author Share Posted September 25, 2009 ill try that Link to comment Share on other sites More sharing options...
Geonovast Posted September 25, 2009 Share Posted September 25, 2009 crap.. i hope thats not the problem cause that thing was a girl to take out. Is there any way to tell if its 21 or 23 spline without taking it off, maybe like a stamp or cast number??? With the trans in park and T-case in 2wd, can you push the truck? If you can move it, there's your problem. But I'd think you'd have noticed if Park didn't hold the truck. another possibility.....your original trans may have been bad, and it could have been a 21 spline output with a matching 21 spline input TC. The ZJ trans is a 23 spline. Your 21 spline TC will bolt up to a 23 spline output tranny, but there's no spline engagement between the two....the output just spins inside the input gear I think you have the backwards. The 21 spline output might spin inside the 23 spline input, but the other way around simply wouldn't go on. Are you sure it wasn't a short/long input conflict? Link to comment Share on other sites More sharing options...
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