AW4 Transmission Swap

['89_Wagon]

I'm running a '97 TCU in a <96 trans (with newer 97+ NSS swapped in, but still running the old reed style single VSS). The '97 brake sense gets switched to ground, open when brake pedal pushed. if this is to be believed:

https://cardiagn.com/4-0l-transmissi...cherokee-1997/

I'm working with Nick at Niftyshifter, will be testing one of his Pro's eventually.

Any advantages to the 97 TCU vs the 96? Did you have the convert the harness or wiring to fit the 96 trans?

That's a pretty neat gadget and seems to be a reasonable price. Curious to hear your experience with it.

My concern with how I'm wiring my brake sensor is that it defaults the circuit to closed (brake off) vs the OEM system of brake on. I'm not sure what kind of effects that will have if my brake pedal sensor fails. I'm using the stock Wagoneer sensor to switch the brake sense circuit on the AW4.

[pickledtoast]

Thanks for the TPS values. I have yet to measure mine, but wasn't sure if your later AW4 tps had inverted values or not. Good to know it doesn't and that I can likely just tap the Sniper tps on mine.

You are correct, voltage between the output pin and ground increases as the resistance between the output pin and ground increases. The TPS is just a simple potentiometer/resistor voltage divider.

Any advantages to the 97 TCU vs the 96? Did you have the convert the harness or wiring to fit the 96 trans?

That's a pretty neat gadget and seems to be a reasonable price. Curious to hear your experience with it.

My concern with how I'm wiring my brake sensor is that it defaults the circuit to closed (brake off) vs the OEM system of brake on. I'm not sure what kind of effects that will have if my brake pedal sensor fails. I'm using the stock Wagoneer sensor to switch the brake sense circuit on the AW4.

I'm using the 97 TCU because that's what the seller gave me when I bought the transmission. At the time I had no idea it came from a different vehicle, or that it mattered.

Per Nick at Niftyshifter, the '97 TCU uses the newer 7wire NSS, so I bought the $39 ebay NSS and swapped it over. But it uses the old single rear VSS that was already on the AW4.

I'm not yet sure on the brake switch. Now I think for '97 it's usually grounded, then gets +12v when the brake pedal gets pressed. I'll play with it when I bench test it all.

['89_Wagon]

Progress has been slow lately... just not a whole lot of time and I'm waiting on studs for the transfer case. Those should be coming in this week.

But, here's some new stuff.

Dip stick installed. This is a shot before bending it. Right now the dip stick is pointing at the air filter housing so I'm going to have to bend it a but. Also, I didn't measure the bolt/stud that the tube mounts to before installing the AW4. I think there's supposed to be a stud, but mine is missing, but there's definitely a bolt hole.... so I have to figure that out.



Here are the parts for converting the transfer fluid in/out ports on the AW4 to 6-AN fittings. O-rings are needed too on the transmission side.

['89_Wagon]

Measured for driveshafts last week but haven't gotten around to taking pictures of how I did it... just to check with you guys if I did it right. I have not ordered custom driveshafts so I would really appreciate some guidance on it.

Anyways, here's what I got for a total length measuring yoke to yoke

Rear- 34"
Front- 30 5/8"

Updated 2/6/20

Here are pics of how I did it. Notice the pates bolted to the yokes. I measured yoke to yoke with the Jeep on the ground and I got the above measurements which were pretty much spot on to what I thought they would be.

2 questions.

Did I measure this right?

Any recommended driveshaft shops? Planning to buy new.

['89_Wagon]

Had to put the project on hold for while due to other priorities but was able to pick it back up it the last few weeks. Here are the highlights.

1. Custom driveshafts are on hand
2. Wiring is done
3. Kick down cable is mostly fitted

Once I jumped into the wiring, things began to snowball. On my first pass of the AW4 wiring install, I noticed I was getting poor grounding on all circuits. The ground cable from the engine block to frame was shot. That was replaced, but somehow solving that problem morphed into taking apart the entire engine bay harness, integrating everything, and moving some of the EFI relays. I am much happier with the wiring layout now.

I made a few changes....

1. I got rid of the AW4 TPS sensor and just used the TBI TPS sensor. That got rid of the 5V stepdown device and also freed up some space on the throttle linkage side for the stepdown cable. That cable linkage seemed like a tougher nut to crack. We'll see if he TPS makes a huge difference.

2. Re-used the cruise control cable bracket for the AW4 step-down connector. This required some careful shaping.

AW4 Kick-down connector. Waaaaay too long. Needs to be shortened.



Bracket Shaped


Everything together.


Now time to shorten the linkage. The connector needs to be taken apart into it's 3 pieces. First, cut the cable from behind the connector. Then cut the crimps out. After that, there's some sort of yellow/clear shield that sits on a ball joint. Remove that. Then, there's a big button/slide that needs to be pressed down and with some wiggle and force, the shaft should slide out. Here are some pics that hopefully make more sense.

Crimps. Note the bronze one on the right.


Here's the shaft that slides out. I used a drill bit to get some of the cable sheath out.


Next, put the connector back together, install on the bracket, and size up the cable length. The cable sheath needs to forced into the back of the shaft removed earlier. Here's where I'm at. Just need to get the right tools and crimps to finish this part.

The bottom one is the AW4 kickdown.



I'll follow up with more pics of the harness.

[Carnuck]

I’m hoping to hook mine up soon to the LPG powered stroker 6 in Black Jack and Chev used to be TBi V8 in my Grumman van. The spare Diesel I have needs an AW4 adapter.

['89_Wagon]

Progress has been slow because my time has beeen soaked up by other things. The good thing is that I put it all together and drove it. The bad news is in my excitement, I overfilled the transmission and killed it. It only took about 1/8 mile. Ooops. Perhaps something else happened, but I'll get a better idea when I tear it down. Ordered another AW4 just to speed up the process and it should be arriving next week. I'll use this as an opportunity to change a few things like the shifter linkage. I will also flush the lines and install a new cooler.

Electrically, I still need to test the torque converter lockup circuit. But, the NSS and backup lights work great. The transmission seemed to shift fine into 2nd... the one time it did.

About a month ago, I wanted to see why my T-case was stuck in Hi and also wanted to reseal the case. The PO sealed it with RTV. In tearing into the top portion, a needle bearing dropping so that led to taking it all apart and putting it back together. It shifts now.. I think corrosion on the outside of the case was sticking it. No weird noises from the t-case.

For the T-case linkage, I used this new for a 02-05 Dodge Ram 4x4. It was $9 on Ebay and came with bushings. I used some other Misc hardware and had to cut it down a bit.



For the hardlines, I first routed them across to the driver's side and then to the front of the engine. I didn't like how many times this got close to the exhaust and also was concerned about it hitting the driveshaft. So I made new lines and ran them along the passenger side instead. There are some simple brackets holding them in place... one at the starter, another at the engine mount, and a third at the front of the engine. Feels solid.







It gets this close to the exhaust. Not much I can do about that since the transmission ports on the AW4 are on the passenger side. Would heat wrap/sleeve be overkill?

[Carnuck]

The hanger by the starter is upside down. It’s supposed to push the tubing down away from the exhaust. The factory one would rattle loose and cut through the lines if the motor shook. BTW, my 304 is going away today so the AW4 Renix flexplate that I had rebalanced for it is for sale now. $100.

['89_Wagon]

Everything is working! Picked up another AW4 from the junkyard, threw it in, and drove it around. Shifted fine and OD engaged. The column shift markings are not aligned but that's just something I can live with.

Shift points seem fine. It downshifts just fine too. Really feels good. Nothing goofy to report. I'm happy that I was able to tap the GM TPS for the AW4 signal. That made things a little more simple. I'll be taking it on more drives so I'll get a better idea.

My speedometer is not working and I'm certain my suspension needs a refresh so that's next on the list.

[Mikel]

Fantastic! Other than the OD, any drivability differences compared to the old 3 speed?

['89_Wagon]

Fantastic! Other than the OD, any drivability differences compared to the old 3 speed?

Unfortunately, the TF727 was on it's way out when I bought the Wagoneer so I don't think I can do a fair comparison. But so far so good! I'll try to post some observations on shift points, smoothness ect. Might be slow in updating as life is busy right now and finding time for the Jeep has been tough.

['89_Wagon]

I've been running this setup for about 8 months and put roughly 1k miles on it, so I thought I would share my impressions. Overall, it's a smooth shifting transmission that feels very natural in the Jeep. The shift points are great and the OD engages at 45 MPH or so under light load. Once engaged, the OD will hang on a little longer than I want to, to about 35 MPH under normal driving. But, a stab of the throttle will downshift it. I haven't had any more issues with the shifter falling apart. I used a better quality U-clamp and try to be more gentle with the shifter. The shifter is stiff though and I just live with the fact that the indicator does not line up with markings on the column. MY MPGs have gone up 1-2 MPG. Not a huge improvement but appreciated. The best part of the swap is going 65 MPH at 1800 RPM. Just a bit more relaxed.

I've driven this in mixed conditions... snow, paved mountain roads, hauling 1500 lbs of concret mix, summer driving, highway, and so on. Transmission did fine with all of them.

FYI, the speedometer issue I was having was unrelated to the swap.

[Mikel]

I've been running this setup for about 8 months and put roughly 1k miles on it, so I thought I would share my impressions. Overall, it's a smooth shifting transmission that feels very natural in the Jeep. The shift points are great and the OD engages at 45 MPH or so under light load. Once engaged, the OD will hang on a little longer than I want to, to about 35 MPH under normal driving. But, a stab of the throttle will downshift it. I haven't had any more issues with the shifter falling apart. I used a better quality U-clamp and try to be more gentle with the shifter. The shifter is stiff though and I just live with the fact that the indicator does not line up with markings on the column. MY MPGs have gone up 1-2 MPG. Not a huge improvement but appreciated. The best part of the swap is going 65 MPH at 1800 RPM. Just a bit more relaxed.

I've driven this in mixed conditions... snow, paved mountain roads, hauling 1500 lbs of concret mix, summer driving, highway, and so on. Transmission did fine with all of them.

FYI, the speedometer issue I was having was unrelated to the swap.

Thank you for updating us.


My XJ also had the habit of not wanting to kick out of OD unless a lot of throttle was applied, so I suppose that's how it's calibrated.


1-2MPG may not sound like a lot, but you are probably talking 10-20% increase in fuel economy, which is quite significant.

[Brynjminjones]

My XJ also had the habit of not wanting to kick out of OD unless a lot of throttle was applied, so I suppose that's how it's calibrated.

Could this be down to the adjustment of the kickdown cable?

My XJ used to be the same. Everybody who drove it commented that it was like it had two speeds - either very slow in the highest gear possible, or drop down two gears and go flat out.

Adjusting the kickdown cable made it much better, and now it's in the correct gear much more often.


That said, mine still keeps the torque converter locked up as you slow to about 40mph, but I like that as I can keep it from revving high and find it much more relaxing (and better for MPG!).
If I need to downshift I just prod the throttle briefly. I generally find it to be a very easy transmission to manipulate using the throttle!

[Mikel]

Could this be down to the adjustment of the kickdown cable?

My XJ used to be the same. Everybody who drove it commented that it was like it had two speeds - either very slow in the highest gear possible, or drop down two gears and go flat out.

Adjusting the kickdown cable made it much better, and now it's in the correct gear much more often.


That said, mine still keeps the torque converter locked up as you slow to about 40mph, but I like that as I can keep it from revving high and find it much more relaxing (and better for MPG!).
If I need to downshift I just prod the throttle briefly. I generally find it to be a very easy transmission to manipulate using the throttle!

You are absolutely correct. When I bought my XJ, it behaved just like yours. I adjusted the trans cable and it worked normally. But still did not downshift out of OD as early as I like. A lot of older 4 sp autos do the same.

I got used to tapping the brake pedal when climbing hills, which would unlock the TC.