6 speed to auto swap

JK12

JK12

New member
How much in really involved in this swap? I've seen a thread on it on another forum and I'm getting tired of my six speed so I thought I would give it a shot if it's possible.
 
I've been thinking about this for a long time, and what I came up with is that.

You will need ;

-a new transmission and torque converter (hope the ring gear fits on the torque, if not, your will also need the flexplate (ring gear for the torque)
-a new set of pedals (clutch and brake) and get rid of your clutch pedal system.
-a new shifter/shifter cable and console because they're different.
-hope that your pcm will do the trick with a reprogrammation for the auto tranny, otherwise you will also need to replace/reprogram a new pcm.
-a new tranny oil cooler and hoses.
-the cross member is also different I believe.


That involve a lot of work and a lot of money. Unless I get a free wrecked jk for parts with an auto, I think I'm gonna stick to my stick :standing wave:
 
I use to love my manuals. Had a YJ and a TJ.

When I bought my JK I went with the auto. I like to wheel the auto just as much as the sticks in the past. But, the 42rle transmission a not a very good trans. Definitely not good enough to buy new and put in as a swap w all the work involved. If you could get cheap parts, maybe.
 
Tcdawg said:
I use to love my manuals. Had a YJ and a TJ.

When I bought my JK I went with the auto. I like to wheel the auto just as much as the sticks in the past. But, the 42rle transmission a not a very good trans. Definitely not good enough to buy new and put in as a swap w all the work involved. If you could get cheap parts, maybe.
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depends if he's talking about the new 5 speed auto or the old 42rle. The only reason why I would put a 42rle is to add a rubi crawler in the tail ;) But I would def. put on the new 5 speed if my wallet was thick enough.
 
From what I've searched the guy did it for around 1500 for all parts but I'm sure that won't be my price. I was trying to figure out the 5 speed auto but I don't know how and what's all involved And I do believe the PCM you have to buy new and have the dealership program it for auto and your vin. I also want to swap out the 3.8 with a lower mileage engine so I can save up for a 5.3 or 6.2 ls. I wanted to see if anyone has ventured into something like this.
 
Holeshot said:
depends if he's talking about the new 5 speed auto or the old 42rle. The only reason why I would put a 42rle is to add a rubi crawler in the tail ;) But I would def. put on the new 5 speed if my wallet was thick enough.
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I forget about the 2012 and up motors and trannys sometimes.

It may well be worth it for the new 5 speed auto Trans. I drive a stock one at a dealership when they first came out and was impressed w the 5 speed.
 
JK12 said:
From what I've searched the guy did it for around 1500 for all parts but I'm sure that won't be my price. I was trying to figure out the 5 speed auto but I don't know how and what's all involved And I do believe the PCM you have to buy new and have the dealership program it for auto and your vin. I also want to swap out the 3.8 with a lower mileage engine so I can save up for a 5.3 or 6.2 ls. I wanted to see if anyone has ventured into something like this.
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If your going to save up for a ls swap, I would just do auto then and not waste the money on the 3.8 with any parts.
 
JK12 said:
Do you think a 5.3 will be ok with high altitude and mountain passes? Or should I try for a 6.2?
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Moochie is running a 5.3L and it seems to do the job great including in high altitudes and mountain passes. I'd talk to him for more details but, I think you'd find it to be plenty.
 
wayoflife said:
Moochie is running a 5.3L and it seems to do the job great including in high altitudes and mountain passes. I'd talk to him for more details but, I think you'd find it to be plenty.
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Alright thanks Eddie! Enjoy that new motor!
 
auto

Save for the LS!!! You will also need to switch one of the ECM cables also to allow the ECM to talk to the transmission. Also you will need a different center counsel and shifter. You would be lucky to spend $1500 after the frustration of changing everything over then loading it up to take it into a reluctant dealer to program in the VIN and hopefully the corrrect milage and other settings they may have never been in before! The Jeep programing is SO strait forward! Dash would displaly correctly but next dealer or owner would see the changes in ECM. VIN checks will come up as a manual so more questions if you ever sell it! Not trying to talk you out of it but spending your energy elsewhere is a better idea.
The 5.3 has plenty for most people but if your plans are to go even half as close to what Eddie did with Moby and use it then think 6.2! You Will Break things with the 6.2! That is why I did not go with one. I tend to push things a little too far and so far the 5.3 hasn't broke anything but a power steering pump and belt! Hence the PSC pump! The belt I think was over tightened and hitting snow banks probably ended that belts life early! Go drive one and you will be hooked!
 
jims68 said:
Save for the LS!!! You will also need to switch one of the ECM cables also to allow the ECM to talk to the transmission. Also you will need a different center counsel and shifter. You would be lucky to spend $1500 after the frustration of changing everything over then loading it up to take it into a reluctant dealer to program in the VIN and hopefully the corrrect milage and other settings they may have never been in before! The Jeep programing is SO strait forward! Dash would displaly correctly but next dealer or owner would see the changes in ECM. VIN checks will come up as a manual so more questions if you ever sell it! Not trying to talk you out of it but spending your energy elsewhere is a better idea.
The 5.3 has plenty for most people but if your plans are to go even half as close to what Eddie did with Moby and use it then think 6.2! You Will Break things with the 6.2! That is why I did not go with one. I tend to push things a little too far and so far the 5.3 hasn't broke anything but a power steering pump and belt! Hence the PSC pump! The belt I think was over tightened and hitting snow banks probably ended that belts life early! Go drive one and you will be hooked!
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Maybe I'll have to take a trip to Vegas to test drive one and quote out the price. I wish there was a way I could get on in the work but I doubt that! Thanks for the advice are you still running stock axles?
 
JK12 said:
Maybe I'll have to take a trip to Vegas to test drive one and quote out the price. I wish there was a way I could get on in the work but I doubt that! Thanks for the advice are you still running stock axles?
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It's in the $20k range.
 
Yes stock 30/44 with trutracs and 4.10's. I am going to see how hard I can push the 30 trussed, RCV's with the higher ratio it should take alot compared to the 5.13's would have. If you provided all of the parts needed for Robbie and delivered jeep to him that should save you a pretty penny! Just round figures 5 grand for kit, 5 grand for motor transmission, 5 grand install that would put you at 15 grand. I did mine for just under 10 grand but the kits have gone up since then also. The 15 to 20 would be accurate and safe estimate by the time you were all done! His new kits only have three wires under the dash to hook up. Hardest part will be getting motor and trany installed! My install the wiring was a lot more complicated since it was one of the first. I also did all of the modifications to the stock wiring but had to re do the whole front end anyway since it was a totaled engine fire vehicle! Hard way to learn all the systems but that way I can fix any problems in the future!
 
Forget about the five-speed auto with the 3.8 engine. The Pentstar with a five-speed auto uses a separate TCM and ECM where the 3.8 uses a PCM which controls both the engine and transmission.

In order to swap to a 4 speed automatic transmission you would need the transmission with converter, shifter assembly, console, shifter cable, key interlock cable, shifter sled (the metal plate that goes under the shifter), A new C100 main engine harness, pedals, crank sensor and a PCM.

The 3.8 engine uses a NGC4 computer. On automatic transmission vehicles all four of the computers connectors are used, on manual transmission vehicles only three of the four connectors are used. Connector C4 is the automatic transmission connector. Connector C4 controls the PRNDL on the dash, transmission electronics and solinoids as well as the other transmission functions including neutral safety.

Good news is done correctly everything will become functional including the PRNDL on the dash, key interlock, brake interlock, lights on the shifter, neutral safety, etc.

The parts are not expensive but it would be a bit of work. In addition the 4 speed auto sucks HP and will not perform as good as a manual 6 speed. The diverse geared, low friction 6l80 can match the manual transmission for efficiency but it is a modern clutch to clutch transmission where the 42RLE is a throwback from the 90's.

We do a lot of manual to auto swaps with the LS conversion (including Moby) and it's easy because the LS is not dependent on the Jeeps goofy can bus electronics:) In most of our manual to auto swaps we keep the original PCM and C100 harness reducing costs, everything is functional except the PRNDL on the dash. The PRNDL on the dash is not required as you have a PRNDL on the shifter and with the gates shifting is intuitive, even my wife drives a LS JK manual to auto swap. Neutral safety, reverse lights and interlocks all remain functional.

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