MonsterJeep Posted November 3, 2017 Share Posted November 3, 2017 I’m having issues with my 1990 Jeep MJ transmission swap going from AX15 to a903. The crank position sensor is different front the manual to the automatic. I tried to wire a 3 wire automatic sensor to my 2 wire manual sensor plug, didn’t work... tried to modify a903 bellhousing to fit the ax15 sensor that didn’t work either. Truck won’t start and is dead in the water. Can anyone get me back on the trail? Link to comment Share on other sites More sharing options...
dasbulliwagen Posted November 3, 2017 Share Posted November 3, 2017 I assume when you say AX15 you're referring to it being behind a 4.0. The A904 auto was never offered behind the 4.0 and thus won't bolt up. Now if your AX15 is actually an AX5 behind a 2.5 or 2.8 then it will bolt up. I can't comment on the crank sensor though sorry. I have a spare A904 sitting waiting for a future project, so I'll be curious how this works out. Good luck. Link to comment Share on other sites More sharing options...
Pete M Posted November 3, 2017 Share Posted November 3, 2017 did it come from a YJ? which trans did they have? Link to comment Share on other sites More sharing options...
Eagle Posted November 3, 2017 Share Posted November 3, 2017 53 minutes ago, MonsterJeep said: I’m having issues with my 1990 Jeep MJ transmission swap going from AX15 to a903. The crank position sensor is different front the manual to the automatic. I tried to wire a 3 wire automatic sensor to my 2 wire manual sensor plug, didn’t work... tried to modify a903 bellhousing to fit the ax15 sensor that didn’t work either. Truck won’t start and is dead in the water. I brought truck to a local shop to finish the swap they recommended as I was and am still baffled. Shop owner called earlier this week said he’s tired of working on my vehicle and doesn’t know how to fix it. Can anyone get me back on the trail? The Crank Position Sensor (CPS) is NOT different for the AX-15 and the automatic. It is, however, different for the 1987-1990 and the 1991-newer model years. Link to comment Share on other sites More sharing options...
carnuck Posted November 3, 2017 Share Posted November 3, 2017 did it come from a YJ? which trans did they have? Editing to fix my timeline mistake: The YJ 3 speed auto 904 is a backwards move for a 4.0L because they suck up power and have no overdrive. The only reason I wanted one for my MJ with 2.5L is because it’s easier to bolt up since I already have the flex plate for 904 with Renix TBI. I looked up the info on YJs because I was told the first ones had Dana 300s with passenger side drop and wrong spline count, but that was wrong info. It was ‘80+ CJ7s with 904/D300 combo. The ‘91 up 32RE (904 or 909) in 4 cyl YJs has a different sensor than Renix years and the sensor hole changed again for OBDII. I have a 999 (32RE) bare case from a ‘99 TJ with 4.0L with valvebody in my for sale stuff. I used the internals to build the 998 in my AMC Eagle 15 years ago. It has the pill bottle style HO sensor and hole. The alignment of the early HO flexplate to the OBDII pill bottle style tone ring is offset different. You can’t use an HO sensor with Renix flexplate or vice versa. I built a 998 (32RH) into a 999 for my Eagle wagon before 1999 (when I found frame rot in both the Eagle wagon and then the ‘83 full size Cherokee a year later after I put in the Eagle’s Mexican 282 with the beefed up 998) The 999 had the better, stronger torque converter and front pump design with bolt in rear sprague but the valvebody was Computer controlled, so I still have the bare 4.0L 32RE case and valvebody from the ‘99 TJ. The lockup converter was the only thing Computer controlled, but I wanted that hooked to a manual switch so it wouldn’t engage while towing or on steep hills on the highway while loaded. The later TJ and Mopar 32RE valvebodies had an issue with clogging up and either not engaging O/D at all or staying engaged and stalling when you came to a stop. Sent from my iPhone using Tapatalk Link to comment Share on other sites More sharing options...
Pete M Posted November 3, 2017 Share Posted November 3, 2017 what year is the trans? Link to comment Share on other sites More sharing options...
MonsterJeep Posted November 3, 2017 Author Share Posted November 3, 2017 55 minutes ago, Pete M said: what year is the trans? I honestly couldn’t tell you, where can I find something to identify? Link to comment Share on other sites More sharing options...
omega_rugal Posted November 3, 2017 Share Posted November 3, 2017 If you want to use that tranny so bad... get a HEI dizzy... Link to comment Share on other sites More sharing options...
kryptronic Posted November 3, 2017 Share Posted November 3, 2017 2 hours ago, carnuck said: You don’t want to run the YJ 3 speed auto 904. I was told the first ones had Dana 300s with passenger side drop and wrong spline count, but that may be wrong. The ‘91 up 32RE (904 or 909) has a different sensor than Renix years and the sensor hole changed again for OBDII. No YJs ever came with pass side drop or a Dana 300. To my knowledge, the TF904/TF999/32RE are basically the same transmission with different names used at different times. They have a 21 spline output. The AW4 is much better from what Ive read. Link to comment Share on other sites More sharing options...
Pete M Posted November 3, 2017 Share Posted November 3, 2017 try to snap some pictures and maybe some numbers from the data plate. Link to comment Share on other sites More sharing options...
carnuck Posted November 4, 2017 Share Posted November 4, 2017 The CJ7s were the ones with 904 and D300 tcase after ‘80 till ‘86 when they were done and the YJs came out but the 904s, like the 4x4 Jeep 727s were all 23 and not 21 spline. YJs were too short to run the AW4 and the same with TJs till after ‘99. The same with 42RE (904 with overdrive and electronic controlled valvebody) AW4 has 21 spline from ‘87 til 08/90 with all Jeep motors. The 904 (or 909 if it’s a lockup) was on the 4 cyl till MPFI in the MJs and XJs. Possibly a little earlier on the 2.5L but those AW4s were 21 spline with a .70 O/D and 4.10 gears. I’ve been looking for the 4 cyl AW4 for my Comanche so I could rebuild my 2.5L motor and have automatic O/D since driving a stick still hurts my previously broken tailbone. The AW4 on HO 4.0L (09/‘90 and up) had a .75 O/D and 23 spline but around ‘96 (OBDII) they added a centering pilot shaft to the output of the Grand Cherokee and some XJs transmissions. Sent from my iPhone using Tapatalk Link to comment Share on other sites More sharing options...
yxmj Posted November 4, 2017 Share Posted November 4, 2017 First to be clear......you are trying to bolt this trans to what engine? second if you have a 904 (the 903 in your subject line is a standard) there will be casting marks in 2 spots on the housing near the starter indent and on the housing near the shiftier rod.....what are these numbers And as said above you will be needing to use your original crank position sensor.....it is not reading information from the trans....it just detects the clocking of the crankshaft Link to comment Share on other sites More sharing options...
carnuck Posted November 5, 2017 Share Posted November 5, 2017 I would hook the 727 I have to my 304 to put in one but I already went with AW4 trying this a few years ago. 904 is pretty weak unless it’s really a 999 updated setup. Unless this is for a Chevy swap with 80-82 AMC Eagle or CJ 4 cyl 904 (Chevy small block pattern bell) Sent from my iPhone using Tapatalk Link to comment Share on other sites More sharing options...
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