Another AW4 to AX15 Swap...

Ok, so I've read numerous threads on swapping AW4's to AX15's, but am hoping to verify a few points.

I'm swapping a 98 4.0l engine and AX15 into a 96 with 4.0l and AW4.

I've read to gather the following from the donor car:
Engine
AX15 Trans
98 ECU
Shifter and baseplate(under carpet)
Pedal assembly
Clutch hydraulics
Crossmember (?)
Both driveshafts
T-Case linkage
Reverse light wiring

I understand that I'll need to unplug the TCU, and wire up the reverse lights and fool the neutral safety switch by grounding.

Should I have any trouble using the 98 ECU in a 96?

I read in one post that I'll have to redrill to mount the t-case linkage... Is that so?

Any other issues/parts I'm going to need?

Thanks in advance!

I'm not sure on a 96 if you need to redrill the t-case linkage mount. You do on the Renix. The AW4 is 1" longer than the AX15. Measuring the differences ahead of time might save you having to redrill it after you put the tranny in the way. btdt.

I would hunt down a 96 and 98 FSM and compare the ECU connectors to make sure they are the same. Otherwise you might be able to use the 96 ECU and leave the trans computer in place so you don't throw a check-engine light. I don't think any of the engine sensors changed between the two years, but some things did change in 97 (like the aw4 trans computer and rear speed sensor on the auto tranny).

I did an AW4 to NV3550 swap in my rig. I would say don't get the 98 engine controller. Just bolt all your 96 stuff onto the donor engine. The TCM can be just removed and forgotten.

Just need to figure out the neutral safety switch wiring. I cut the wiring pigtail from the AW4 neutral safety switch and made my own trans wiring harness.



One issue I had with just using the Auto ECM was the controller wanted see a change in state from park/neutral to drive. If it didn't see this change it would turn on the check engine light on. What I did to fool the engine controller is to run the neutral safety switch wires over to the clutch pedal electrical switch. Every time you step on the clutch the trans thinks it is in neutral, when you let your foot off the clutch it thinks you are in drive. Problem solved. The back up lights were pretty easy to figure out too. If you can grab it, take the trans wiring harness from the donor vehicle.


Another issue you might have is with the clutch master and pedal. When I did my swap I used a 97+ clutch master tube and slave assy. Worked out great, but the clutch pedal stuck way to far up, almost 2" higher than the brake pedal. I had to cut of and re-index the clutch pedal so it would work.




Don't know anything about the t-case linkage or cross member issues. On my set-up I have a Clayton long arm cross member and I swapped in an atlas at the same time as the trans.

All my pics can be found here: Trans Swap Pics

Great info guys. Thanks!

I've since pulled all the '98 parts, including the trans harness and pedal assembly(that's fun...).

Looks like a challenge to install the pedal assembly in the '96, as things like the fuse panel are nearby. In fact, it doesn't look like I'll be able to use it, cause the mounting arrangements so different. Think I'll have to hunt down a pedal assembly from a 95-96...

Hey, good news! She's up and running...

Now I'm re-tracing the steps other's have taken to overcome the lack of a Park/Neutral switch. Following guidance from a swap write-up, I jumpered the wires to the P/N switch allowing the engine to start. Now I get a check engine light cause the ECU doesn't see the P/N state change...ever (it's a '96).

The fix mentioned above suggests using the clutch switch, but those only exist on '97 or later whose clutch master pushrods have an integrated switch. I could swap one over, but they're too long and cutting/welding looks challenging while still allowing the switch to work.

Any one have a different solution (other than a new ECU)?

Thanks!

No ideas on how else to fix the CEL, but congrats on the swap!

What error codes are you getting? Did you leave the TCU in place? If the ECU doesn't see the TCU you'll get a code P700 (unless you swap in a manual version of the ECU). A P705 would mean its the TCU thats upset about the nss not looking right.

I was getting a 'no change in Park/Neutral switch state' error code (don't recall the number). It's fixed now.

What I ended up doing was to disconnect the prior jumpered B/C wires on the black trans connector (to P/N switch) and ran those two wires to a generic clutch switch (actually GM brake switch). I had to extend the the factory brake switch mount mount (tacked in 12g sheet metal) to align it with the clutch pedal.

Now you have to push slightly on the clutch to start it(safety), and the P/N switch state changes with every shift so the ECU is happy.

On to the next challenge....

Gotcha. I'd guess that error code is generated if the TCU sees the car start to move (based on the rear speed sensor) and the NSS is still showing the tranny is in park. Glad you found a work around.