Options for those who want overdrive on their TJ (42RLE vs AW4 vs ?)

[Wildman]

I’ve gone down the rabbit hole of the 8h70 along with other transmission and they are the “new kid” on the block but they have several drawbacks as well. Length, weight, and cooling complexity as well. The 8hp70 needs it’s own dedicated transmission cooler, it can not be integrated into the factory radiator. Also for all the controls that “work” with the 8hp70, they need WAY more information from the CANBUS to operate, percentage of torque, percentage of load, and several other data points that I can’t remember off the top of my head. I’m not saying it’s not possible but the length, weight and all the information required from the engine ECU to run it properly is the main concern. I looked at bolting the 8hp70 to my BEW TDI and the TDI ECU did not have the correct parameters required to operate the 8hp70. Just something to keep in mind.


I’ll go back and re-read the entire thread to see if I missed anything.

Thanks
Grant

I've got to disagree with you on a lot of this.

1) Cooling- From talking to those who have used the 8HP in swaps they have had no issues using the cooler in the radiator. A few have needed to add an aux cooler. You don't even have to use the stock heat/cooler that comes on the transmission.

2) CANBUS- There isn't any "CANBUS" signal needed using the SoundGerman wiring harness. The folks who have been using the 8HP in a Hot Rod or drag racing rig have been able to work around the need of the "CANBUS" signal but in our DD type rig from all I've gathered it's not needed.

3) Dimensions- I haven't weighed my 8HP but as I remember it was lighter than the 545RFE but don't hold me to that. And yes, it is long but how does it compare to the AW3 or 42RLE length wise?

Edit: This file is Word so I can't attach it here but here are the inputs needed to make the 8HP work with the wiring harness kit from SoundGerman.

8hp kit installation instructions.

The 8hp kit is as close to plug n play as possible. The required inputs for the transmission to work with this kit are RPM, TPS, Torque, Brake switch or Brake lamp input. All other wiring is optional and for your use as needed. We provide Neutral safety output and Reverse light output to ground only. These are outputs from the kit. Not inputs and are to provide these signals to your vehicle to a starter relay or a reverse light relay. Speedometer output is a programmable and should work with any modern electronic speedometer or a speedometer driver such as Speedhut Speedbox. C4 for CAN is not used.

I can share the files if anyone is interested.

 

[Negreac]

I've got to disagree with you on a lot of this.

1) Cooling- From talking to those who have used the 8HP in swaps they have had no issues using the cooler in the radiator. A few have needed to add an aux cooler. You don't even have to use the stock heat/cooler that comes on the transmission.

2) CANBUS- There isn't any "CANBUS" signal needed using the SoundGerman wiring harness. The folks who have been using the 8HP in a Hot Rod or drag racing rig have been able to work around the need of the "CANBUS" signal but in our DD type rig from all I've gathered it's not needed.

3) Dimensions- I haven't weighed my 8HP but as I remember it was lighter than the 545RFE but don't hold me to that. And yes, it is long but how does it compare to the AW3 or 42RLE length wise?

I just measured the AW4 I have it is 25.75" long from bell housing to transfer case mounting surface. So about 2.25" shorter that the 8HP70.

 

[Wildman]

I just measured the AW4 I have it is 25.75" long from bell housing to transfer case mounting surface. So about 2.25" shorter that the 8HP70.

That helps.... So if you had a SSYE you should be OK as far as driveshaft length. Isn't a perfect swap but not undoable.

Here's a guys TJ with a 6.1 Hemi & 8HP70 swapped in. He's overseas so I'm not sure which rig his shifter came out of.

Edit: He's in Greece so IMO it's a cool build on that merit alone.

 

[Negreac]

I just got back from a work trip and I’m playing catch up on this thread but wanted to give my two cents on everything very quickly.

The AW4 is a great cheap automatic and you can solve all the problems with it over heating by swapping in a later valve body out of a Toyota Tacoma A340 automatic that has a solenoid to control line pressure. Yes that means you need a CompuShift controller to control the transmission but that basically fixes any issues you might have with the AW4 along with getting a ton of tuning options as well. It also has the benefit of bolting directly to the 4.0l engine and all the transfer cases that came in a TJ as well. Understand the CompuShift is the biggest expense here.

I’ve gone down the rabbit hole of the 8h70 along with other transmission and they are the “new kid” on the block but they have several drawbacks as well. Length, weight, and cooling complexity as well. The 8hp70 needs it’s own dedicated transmission cooler, it can not be integrated into the factory radiator. Also for all the controls that “work” with the 8hp70, they need WAY more information from the CANBUS to operate, percentage of torque, percentage of load, and several other data points that I can’t remember off the top of my head. I’m not saying it’s not possible but the length, weight and all the information required from the engine ECU to run it properly is the main concern. I looked at bolting the 8hp70 to my BEW TDI and the TDI ECU did not have the correct parameters required to operate the 8hp70. Just something to keep in mind.

You can be into the AW4 with a parts A340 for the valve body and the CompuShift controller for under 2K. For setting up the transmission in the CompuShift software you’ll need to say you are running a Toyota A343 transmission which was the same gearing as the AW4 but the software to handle line pressure.

I have not had a single over heating issue with my AW4 since I put in the Toyota A340 valve body where line pressure is controlled by the CompuShift ECU and the only cooling I’m running currently is the factory TJ Wrangler radiator. In terms of space, length, and easy of install, the AW4 is the transmission of choice from me. Also you can get the XJ Cherokee shifter for it and it will factory bolt into the TJ center console as well.

I’ll go back and re-read the entire thread to see if I missed anything.

Thanks
Grant

Did you ever run the AW4 without the A340 valve body? If so, any noticeable change in efficiency aka how many boat anchors you feel like you are dragging?

 

[Negreac]

That helps.... So if you had a SSYE you should be OK as far as driveshaft length. Isn't a perfect swap but not undoable.

Here's a guys TJ with a 6.1 Hemi & 8HP70 swapped in. He's overseas so I'm not sure which rig his shifter came out of.

Yeah well the AW4 is ~3" longer than a 32RH so the SSYE more than makes up for that (~6" shorter than vs stock slip yoke). If you add another ~2.25" plus a 0.7" bell housing adapter to that SSYE probably about 1" shorter than the OE 32RH location, not ideal but probably manageable if the lift isn't too big. Still have yet to find anyone who can tell me how long a 42RLE is. Worst comes to worst I can message one of the sellers on FB and ask them to measure.

8HP70 (0.7" Bell Housing Adapter via @Wildman) - ~28.7"
6R80 / 80LE (0.7" Bell Housing Adapter & T-Case 3.625" T-Case Adapter via @Jezza ) - ~
AW4 - ~25.75"
42RLE - ???"
32RH - ~22.75"

Add trans lengths, combine 6L80 with 6R80, and added some more conditional formatting to the chart:

 

[Rickyd]

Ax15,nv3550,42rle are all close to 24"

42re 28"

 

[Negreac]

For reference when I was talking with the builder of that AW4 swapped Sahara TJ that won Rebelle Rally he was right at the limit of what is possible in a stock TJ wheelbase.

With a 44 rear at full droop with the 8+" travel shocks it's 2-3 degrees away from bind on the rear CV. That is with an SSYE on short arms (stock length) with a full flat belly. Drive shaft was ~17" yoke to yoke at ride height. The SSYE offset the extra 3" of length of the AW4 bringing it closer to a standard SYE on a 32RH but the flat belly raised the T-case 2.5" so with the 3" lift about equivalent to a 5.5" lift on a 32RH with standard SYE which is about the limit on a TJ.

Build details from original craigslist posting for reference:

 

[Negreac]

Ax15,nv3550,42rle are all close to 24"

42re 28"

So the 42RLE is only 1.25" longer than a 32RH? Thought it was much longer than that.

 

[Negreac]

The AW-4 has a default OD off. The shifter is 1-2 for the first position, D, then OD. The other problem you mentioned is keeping it in 1st. That is a non-issue. We never had one shift to 2 when it was not okay to do so. The difference between .75 and .69 is one gear step or about the same 5%.

I've never said 10% because I have no way to quantify that. If driving around with what feels like dragging an anchor is quantifiable, then assign a number. Otherwise just understand that they are power robbing pieces of shit.

So if I am reading this correctly you see no practical purpose for something like the Montana Fab AW4 Override Switch? https://montanafab.com/product/aw4-override-switch/

"The AW4 Transmission Override works in conjunction with the gear shift lever to release the computer’s control of first and second gear. The override consists of a rotary switch that is mounted on the dash. The override has three positions, “D”, “2”, and “1”. In the “1” position the transmission will maintain first gear regardless of the computer’s status, rpm, and speed. Engine braking in first is available when the gear shifter is in the “2-1” position, otherwise the transmission will freewheel. Freewheeling is accomplished by the hydraulics in the transmission and prevents damage when the override is accidently activated at high speeds. While in the freewheeling mode the transmission will still provide power. In the “2” position the transmission maintains second gear. This position will allow starting from a stop in second gear and will provide engine braking when the shifter is in either the “3” or the “2-1” position. When the override is in the “2” position and the shifter is in the drive position the transmission will freewheel. The final position in the override is the “D” position. In the “D” position the override has no effect and the transmission shifts normally."

 

[mrblaine]

So if I am reading this correctly you see no practical purpose for something like the Montana Fab AW4 Override Switch? https://montanafab.com/product/aw4-override-switch/

"The AW4 Transmission Override works in conjunction with the gear shift lever to release the computer’s control of first and second gear. The override consists of a rotary switch that is mounted on the dash. The override has three positions, “D”, “2”, and “1”. In the “1” position the transmission will maintain first gear regardless of the computer’s status, rpm, and speed. Engine braking in first is available when the gear shifter is in the “2-1” position, otherwise the transmission will freewheel. Freewheeling is accomplished by the hydraulics in the transmission and prevents damage when the override is accidently activated at high speeds. While in the freewheeling mode the transmission will still provide power. In the “2” position the transmission maintains second gear. This position will allow starting from a stop in second gear and will provide engine braking when the shifter is in either the “3” or the “2-1” position. When the override is in the “2” position and the shifter is in the drive position the transmission will freewheel. The final position in the override is the “D” position. In the “D” position the override has no effect and the transmission shifts normally."

If no one ever told you the AW-4 had an issue staying in 1st under any condition we use it for, you would never know it was a problem. We have wheeled them extensively in this part of the world and not a single time has it ever been an issue.

 

[Wildman]

So push the axle back an easy 4" and you'd regain all your lost driveshaft length... Doesn't seem like too bad of a deal if you were going to all the trouble to swap in an 8HP... Or AW4 or other longer auto transmission.

 

[Negreac]

So push the axle back an easy 4" and you'd regain all your lost driveshaft length... Doesn't seem like too bad of a deal if you were going to all the trouble to swap in an 8HP... Or AW4 or other longer auto transmission.

Exactly what I plan to do for my personal build (4-5" stretch) but looking at it from more of general swap perspective, which most people doing swaps aren't also stretching. Granted most people are not going to consider a modern 8 speed Auto either since it doesn't exactly "bolt-in" without adapters.

 

[jeepguy03]

That helps.... So if you had a SSYE you should be OK as far as driveshaft length. Isn't a perfect swap but not undoable.

Here's a guys TJ with a 6.1 Hemi & 8HP70 swapped in. He's overseas so I'm not sure which rig his shifter came out of.




Edit: He's in Greece so IMO it's a cool build on that merit alone.

That looks like a BMW shifter out of a 2012+ 3-series or other BMW car/SUV with the ZF 8 speed. Makes sense if he is overseas the parts for those cars are easier to come by.

 

[Rickyd]

So the 42RLE is only 1.25" longer than a 32RH? Thought it was much longer than that.

The tailhousing on the 42rle is empty. With a short custom adapter and stub shaft adapter it could possibly be shorter than the 32rh. Look up the rubicrawler to see what I mean

 

[Wildman]

Exactly what I plan to do for my personal build (4-5" stretch) but looking at it from more of general swap perspective, which most people doing swaps aren't also stretching. Granted most people are not going to consider a modern 8 speed Auto either since it doesn't exactly "bolt-in" without adapters.

I can tell you that if you want 5" out of your stretch but are keeping the body stock looking it's tight quarters. I pushed my CRD60 back 5" along with the hump for uptravel. And I could barely fit the shock towers into the body. And then getting the fuel filler hose hooked to the GR fuel tank isn't a load of fun either.
But as you said, if somebody was trying to slap a 8 speed behind the 4.0 already then doing a WB stretch ain't much more to think about.

That looks like a BMW shifter out of a 2012+ 3-series or other BMW car/SUV with the ZF 8 speed. Makes sense if he is overseas the parts for those cars are easier to come by.

I wasn't sure which model it was but figured it for a BMW. I like the looks of it over the Challenger shifter too to be honest.

The tailhousing on the 42rle is empty. With a short custom adapter and stub shaft adapter it could possibly be shorter than the 32rh. Look up the rubicrawler to see what I mean

That does add to it's draw. Now someone just needs to try out that standalone PCM for it to see how it plays out.

 

[jeepguy03]

I wasn't sure which model it was but figured it for a BMW. I like the looks of it over the Challenger shifter too to be honest.

Yeah it came in quite a few BMWs across a certain model year range. It does look better, but I hated it on my friend's 335i. It is nicknamed the "video game controller" in the BMW world because it feels cheap and plastic. I much prefer the shifter in my 2019 Grand Cherokee, not sure if there is a way to swap that on instead.

 

[ColoJeep]

Yeah it came in quite a few BMWs across a certain model year range. It does look better, but I hated it on my friend's 335i. It is nicknamed the "video game controller" in the BMW world because it feels cheap and plastic. I much prefer the shifter in my 2019 Grand Cherokee, not sure if there is a way to swap that on instead.

My old director had a new 2012 435i , I gave him a hard time about his Fisher -Price shifter in his $65,000 BMW , but it went well with a weird rumble under load from what I thought was the AWD system.

 

[Wildman]

Yeah it came in quite a few BMWs across a certain model year range. It does look better, but I hated it on my friend's 335i. It is nicknamed the "video game controller" in the BMW world because it feels cheap and plastic. I much prefer the shifter in my 2019 Grand Cherokee, not sure if there is a way to swap that on instead.

Well I got a little more info from the owner of that rig & shifter. He's able to use it because he's using the Turbolamik controller instead of the standalone harness from SoundGerman. It does give some options/features that the SoundGerman kit doesn't.

 

[jeepguy03]

My old director had a new 2012 435i , I gave him a hard time about his Fisher -Price shifter in his $65,000 BMW , but it went well with a weird rumble under load from what I thought was the AWD system.

They are quick cars but I much prefer the driving dynamics and steering feel of the Pre-2012 cars. The couple that I owned were the 2006-2011 E90 generation 3-series. RWD only of course, like a real sport sedan should be.

 

[ColoJeep]

They are quick cars but I much prefer the driving dynamics and steering feel of the Pre-2012 cars. The couple that I owned were the 2006-2011 E90 generation 3-series. RWD only of course, like a real sport sedan should be.

His previous BMW was a 05 335x with an auto trans that was signing off. I love the concept of BMW , but I'm not sure I would be happy with the reality.