AW4: Converting to 23 spline

[BlueGerbil]

I have to convert my AW4 in my 1990 trail XJ from 21 to 23 spline because I´ve stumbled upon a cheap 4:1 Rocktrack 241OP.

Is there an easy way to convert my AW4 to the 23 spline output shaft of the 1991+ AW4 or can I just swap in an AW4 from a 1991+ XJ ? I can get a newer AW4 for cheap but I´m worried about the electronic stuff...

Thanks!

 

[5-90]

I have to convert my AW4 in my 1990 trail XJ from 21 to 23 spline because I´ve stumbled upon a cheap 4:1 Rocktrack 241OP.

Is there an easy way to convert my AW4 to the 23 spline output shaft of the 1991+ AW4 or can I just swap in an AW4 from a 1991+ XJ ? I can get a newer AW4 for cheap but I´m worried about the electronic stuff...

Thanks!

There weren't many changes in the AW4, apart from the 21-23 spline swap (1989 or so) and the added/changed vehicle speed sensor (1996 or so.)

Get a 1990-1995 AW4 and drop that in - it will be easier than converting the output. You need to do a full overhaul to get to the thing in the first place (since the transmission loads from the front, you have to take everything out to get to the output shaft!) so you may as well swap the box anyhow. If you want to take a shaft from a donor, that's two boxes you'll have to take entirely to bits...

I'm sure OBD-I uses the same speed sensor as RENIX, thus the 1995 cut-off.

(Oh - and check your existing spline count before you go into all the work. The splines were changed when the BA-10 was replaced by the AX-15 in production rigs, circa AUG1989 or so. You may not need to swap in the first place!)

 

[jeepcomj]

i can pin the output shaft change to mid 1990. as stated, the output shaft is a bad idea to swap because of the fact that you will have to do a complete tear-down on the tranny.

speed sensors were changed in 1991 to electronic, but the holes for them are the same, so that shouldn't really be a concern.

 

[BlueGerbil]

So, does that mean: I get a AW4 from a 1990-95 XJ w/ the 23spline output shaft and reuse the speed sensor from my 21spline AW4 ? Just plugging it into the same hole?

Any other cabling stuff to worry about? Any computer stuff to get from the donor vehicle?

I´m asking that detailed since we´ve no junkyards with tons of jeeps over here in europe.

Thanks in advance!

 

[5-90]

I believe that the speed sensor was the same through the OBD-I years (rotor and reader,) so you'll be find there. Also, the control unit didn't change much, either.

Speedometers were changed to electronic, but the speed sensor in the transmission reported to the ECU, not the IP. The speedometer takes its reading from the transfer case tailcone (if you're 4WD,) since shifting into low range would invalidate the transmission's reading (because of the extra gear reduction step.)

But, I honestly think that sticking with 1991-1995 donors will simplify things for you the most - so good luck with that!

(I guess Europeans tend to drive their cars into the ground more than we do here?)

 

[lawsoncl]

I'm about 95% sure the sensor change was in 97/98. The 4th gear ratio changed from .705 to 0.75 at the same time the spline count changed. Shouldn't be an issue although you might notice the 3/4 downshift happening in a slightly different speed. NSS changed somewhere along the line too.

 

[dopod]

The sensor change wasn't in 95/96. I just swapped out an early 90s 23 spline aw4 into my 96 and they were identical. I was told it was around 98, but I am not sure.