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Renix AW4 & HO AW4 Compatibility

old_man

old_man

NAXJA Forum User
Location
Loveland, Colorado
I am running a Renix era AW4 and need to replace it. I have a chance at an AW$ from a 98. What are the differences and can I make it work?
 
get the t-case with it, renix=21 spline HO=23
Other than that I believe they're pretty much bolt in.
 
I have all of that. The tcase isn't an issue and the flex plate isn't an issue. The question comes up as to interfacing to the electronics. I have a Renix AW4 in my rig and it crapped out. I have the option to get a 1998 AW4. What will be the issues?
 
Old Man-
I think Brett has mentioned a few differences around here before between the 1984-1996 and 1997+. I believe something in the tailhousing changes or something in the 97+ units, I don't recall off hand but like I said, I'd talk to him, he is kind of the authority in this area.
 
the spline count is different and the sensors are all different. you will have to replace the 98+ sensors (OBD II connectors) with the renix ones that are pre-OBD.
 
I know on the Renix era AW4's there is the tranny-comfort switch that the H.O. Jeeps never had so maybe there'll be an electronic issue but mechanically with what's been said and what you have access to it should work.
 
Zoro said:
I know on the Renix era AW4's there is the tranny-comfort switch that the H.O. Jeeps never had so maybe there'll be an electronic issue but mechanically with what's been said and what you have access to it should work.
Click to expand...

That's an electronic difference, but it's in the control unit electronics, and not in the slushbox internals.
 
electronic speedo, but the sender is interchangable. also in the later years the TCM was part of the ECM, making it a PCM.... dont know what that effects though
 
5-90 said:
Shouldn't be any - I don't recall any internal mechanical or electronic changes, apart from what was already discussed (output spline and flexplate.)
Click to expand...


When they switched to ODBII in 96/97, there were two sensor changed on the AW4.

1) A front input shaft speed sensor was added so the trans computer could diagnose problems like a bad shift or lockup soleniod and verify it's in the proper gear. This is the reason an ODBII XJ throws an error code if you wire in switches to manually shift the tranny.

2) The rear speed sensor changed type and pulses/rev. The older sensor was a magnetic reed switch that closed once per rev. The newer sensor is an inductive sensor that gives 4 a/c pulses per rev. The rotor on the shaft went to 4 lobes instead of 1. This sensor is on the drivers side under the xfer case shifter linkage bracket.

But the good news is that you can still use the 98 AW4.

You'll have to pull the the tailcones off, swap over the older rotor and use the older speed sensor. If you have the FSM, it has a diagram which makes the swap look pretty simple. You pull the adapter housing (no need to remove the pan), remove a snap ring, and use a piece of wood or dowel to pry the rotor rearward until it slides off. Once you swap the rotors, the older/longer sensor should bolt right in. You can leave the front speed sensor unconnected since the older TCU has no inputs for it.


-Chris
 
lawsoncl said:
When they switched to ODBII in 96/97, there were two sensor changed on the AW4.

1) A front input shaft speed sensor was added so the trans computer could diagnose problems like a bad shift or lockup soleniod and verify it's in the proper gear. This is the reason an ODBII XJ throws an error code if you wire in switches to manually shift the tranny.

2) The rear speed sensor changed type and pulses/rev. The older sensor was a magnetic reed switch that closed once per rev. The newer sensor is an inductive sensor that gives 4 a/c pulses per rev. The rotor on the shaft went to 4 lobes instead of 1. This sensor is on the drivers side under the xfer case shifter linkage bracket.

But the good news is that you can still use the 98 AW4.

You'll have to pull the the tailcones off, swap over the older rotor and use the older speed sensor. If you have the FSM, it has a diagram which makes the swap look pretty simple. You pull the adapter housing (no need to remove the pan), remove a snap ring, and use a piece of wood or dowel to pry the rotor rearward until it slides off. Once you swap the rotors, the older/longer sensor should bolt right in. You can leave the front speed sensor unconnected since the older TCU has no inputs for it.


-Chris
Click to expand...
Sounds like you know what you are talking about. Do you do this for a living?

I'm going to pull the pressure numbers tomorrow. I get good shifts into reverse but not into forward gears. If the rpm's come up enough, it will go ahead and shift and keep shifted once speed is up. This is a tranny from a donor. I put it in and it worked the first trip to the grocery store:D I came back and parked it. The next time out it started the problem.
 
If the tail cone is off, how hard is it to swap the output shaft?
 
Only In A Jeep XJ said:
X2 just out of Curiosity make it a little cheaper on the swap.
Click to expand...

the AW4 uses a nearly full length shaft from input to output. you need to totally strip down the tranny to bare case to get it out. IVe done it to convert a 2x to 4x tranny........not fun.
 
old_man said:
Sounds like you know what you are talking about. Do you do this for a living?
Click to expand...

Nope, I just ran into this issue swapping a 99 AW4 into an 89 manual using an 89 TCU. Everything bolted up great and I got all the wiring done, but it kept upshifting at 1000 rpm despite having it floored. That's when I started doing the homework and sorted out the electronic issues. Comparing the pictures from an 98 and 95 FSM is where I figured out the pulse count differences. I didn't have a donor to swap rotors, so I solved my problem by building a small electronic box to convert the rear speed sensor output.
 
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