yj ax-15 swap for tj 3sp auto

[yjdave]

any problems replacing my 94ax-15 for a 2000 tj automatic. Not concerned with milage, plan on running 36-37 inch ss .and have 4-11 with my 4.0. Mainly questioning the crank sensor and any computer glitches.

 

[Snitty]

i'm not sure if everything is the same or not... one big thing to look out for is the positioning of the crank position sensor

 

[Bounty__Hunter]

Depends on the year YJ, and the output shaft design of each transmission. The output shaft design often varies between manual and auto trannies, they may both be 23 spline but different length.

Click HERE for some great info on the differences in the NP231 input gear and the correct one to make your swap work.

You will be losing your overdrive 5th gear, as the tallest gear ratio in the YJ auto is 1:1. I'd look for an overdrive auto if you're set on having an automatic.

 

[Snitty]

with gas prices the way they are now... that would be the right choice, to make sure you have overdrive... i can't imagine how gas costs would be in an auto, especially with the axle gearing they have

 

[Green97TJ]

how mileage would be with an auto? Try 15 or 16 mpg out of a 4cylinder. Ive got a 97TJ with a 4banger auto. The automatic 4 cylinders have 3.73 gears from the factory. Im running 30x9.50's so they're a little bigger then stock, but not much. I think it might be screwing with my odometer a little tho, so i might be getting slightly better mileage then that.

O well.. just thought id throw all that out there if anyone cares

Nathan

 

[Snitty]

with the 6 cyl... its got a final ratio of 3.73:1 with the 1:1 transmission ratio... that's going to use a lot more has than the manual with the overdrive,and the 3.07 gears