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Any info for 6-spd to automatic swap?

31K views 103 replies 28 participants last post by  deftones07 
#1 ·
I have picked up a 2009 automatic trans, harness, shifter, etc. for this swap.
I know it will have to be taken to the dealer for a program. Has anyone done this? Also, will I need a new computer for the swap? It is the one thing I didn't get. Any info would be greatly appreciated.

Reasons I am going to the trouble:
1. I sold the manual trans for more than the auto and parts cost me
2. My wife will be able to drive it
3. Rubicrawler, so I won't have to regear my axles (currently 5.13s and 40s)
4. The labor of putting my old trans into another jeep offsets the Rubicrawler by a good bit
5. Do I need another reason?
 
#2 ·
you will also need a condensor with an auto trans cooler in it and tranny cooler lines
 
#3 ·
Actually a stand alone cooler will work just fine rather than swapping the radiator out.

Assuming there is a control module associated with the automatic. As well as a different set of pedals, shifter assembly, etc.
 
#15 ·
I would swap for another wife before swapping to an auto. First date with my wife we rode motorcycles, she kicked ass, I married her. Never had a lame bike or car with an auto in our 20 years together.
 
#37 ·
congratulations. but autos have their place. I've had 2 jk's one with a stick and one with an auto. i'll take the auto off road all day long. that being said my crawler is a stick. i'd eventually like to change it to a V8/auto rather than the stroker/ax-15

what a pita. I would have traded it in on an auto or taught your wife to drive standard, there are videos on you tube to help her.
see what a dealer gives you for a JK on 40's lol
 
#16 ·
I'm in the process of doing the same swap. I'm currently gathering parts and it's actually going to be an extremly cheap mod. Good call on the stand alone oil cooler. It will work considerably better than the factory one and it will save you a few hundred $. You do need to purchase a brand new computer. The dealer will need to put a fresh burn into the new ECU with the automatic shift points and they will also be able to burn in your VIN so that it's all legit. Have you picked up the shift interlock cable for the steering column? There will be no issues with driveshaft length so don't worry about that. Also don't forget the shifter lever sled (or bracket) you'll need the automatic version so you can plug the hole on the floor where your manual shifter came through. The programming was my biggest concern because the security system talks to the ECU and allows you to unlock and start your jeep. Now that I found out that the dealer can burn and flash the fresh ECU with all the info I'm all in on doing the swap. I'll keep an eye on your thread and we can trade info and all the in's and out's on pulling this off
 
#18 ·
Well first off they are two different computers. Second, the architecture on the PCM is reflashable, certain information is, but the initial burn cannot be altered. Shifting isn't the issue to begin with, it's the VIN information on the PCM that is the concern. Technically I could just score anothe ECU from any Rubicon and be good to go, but my security wouldn't recognize the VIN and then I wouldn't be able to start my Jeep. Trust that alot of "outside the box" thinking has gone into committing to this project and the one undeniable fact is...a new PCM is required
 
#24 ·
What is the cost of this mod? if its a reasonable, then I am willing to switch my auto for a 6-speed.
 
#28 ·
Do yourself a huge favor and drive an automatic JK before you do the switch.

The tranny gearing in JK automatics is terrible when mated to the JK engine.

I have a 6 speed and my wife has an automatic.

Having driven both, I would never ever suggest a JK automatic to anyone who is not either doing a supercharger, running 5.38s on 35" or smaller tires, or doing a hemi/automatic upgrade.

Most all the guys who complain about the underpowered JK engines are guys with automatics--who often don't know they are really complaining about the tranny gearing matched to the JK engine.

The 0.69 overdrive/4th gear is way too tall for the 3.8L engine.

Even guys with the 4.0L TJ engines routinely complain about power when they have the same automatic tranny gearing.

If you never have to drive at highway speeds, then it is not as big of a deal because you won't spend much time in the 0.69 overdrive gear.
 
#29 ·
I know what you mean. I did drive a 4dr with 5.38s and 37s, and it seemed like a dog compared to my 5.13s and 40s. An engine swap is in the works, so the pedal, sled, console, shifter, etc will be needed anyway. The extra funds from selling the 6spd, transfer case, and the cost of swapping it for that guy made this free for me and funds for an Atlas. So, on road performance will suffer a great deal, but off road gearing is going to improve. I like the downhill engine braking of the manual, but I'll be more capable off road since Ive been running autos for the last 10 yrs. and feel more comfortable with them. I won't miss the 6spd clacking at slow 4low anymore either!:)
 
#30 ·
That is good to know what you are in for.

5.38s and 37s with an automatic being a dog compared to 5.13s and 40s with a 6 speed is exactly the same combination my wife and I have.

I used to wheel all the time with my TJ automatic. It was really great in the rocks.

After I bought my 2 dr 6 speed Rubi and ran 35s on stock 4.10s in the rocks, I almost sold my jeep after a particularly frustrating day in a dry creekbed full of large boulders.

However, one of my friends convinced me to regear it to 5.13s first and made me aware that a 6 speed can be started in 4 lo without the clutch engaged.

With the Rubi 4:1, 5.13s and 35s with the ability to start the engine without worrying about the clutch, I found that my crawl ratio was low enough that it was actually better in boulder gardens than the automatic.

With an automatic, I would need to pre-load the accelerator with a foot on the brake to get out of compromising situations.

With the 6 speed, I could use the starter to crawl out of the compromising situation.

That feature, along with the engine braking cured me of the desire to ever have an automatic jeep again.

This summer we bought a former UROC Suzuki buggy that ran in the 2004 season. It has dual Suzuki transfer cases, a doubler, and 5.89 gears with a Suzuki 5 speed on 37" sticky Krawlers with full hydro steering. It is geared so low that my 12 year old daughter can drive it most anywhere. It is actually easier for her than an automatic would be.

Pic from former owner wheeling in NM:

 
#38 ·
all those toyota guys build em that way. talk about lack of power! rather than swapping for a decent drivetrain they just leave the underpowered yota motors and gear the hell out of them.

They absolutely bring the suck here in the northeast where you often have muck on the rock and need wheelspin.
 
#31 · (Edited)
Planman I see where you're coming from. I currently run 4.10's with 35's and it's not always a enjoyable experience on the rocks. As a matter of fact it can be extremely dangerous at times. I'm re-gearing my rig next month and I'll see how my 6 spd acts on the trail and that will determine whether or not I push up my time line on the tranny swap or abandon the idea all together. All the other JK's I wheel with all have auto's and I've driven there's and see what you mean about the overdrive gears. They run 5.13's with 35's but have not done anything to let the PCM know what the shift points need to be to compensate for the larger tires and higher gears so it's hard for me to truly gauge performance at highway speeds. However, life on the trail is considerably more convenient with a auto and not have to deal with stalls and constant brake, gas, and clutch magic on ridiculous inclines gives me a chub. Plus an automatic would increase my :beer: drinking performance on the trail as well :D

I do have a question for you though. What gears do you recommend I go to? I'll be running 37's once the re-gear is complete and the majority of the people I talk to recommend 5.13's because I still drive my JK on a regualr basis and it hasn't been retired to trail use only status. I suspect if I went to 5.38's my RPM's would be crazy high and I'd burn through gas like crazy. I'm currently still running my manual tranny and as you know I'm planning on swapping to a auto tranny. Are 5.13's going to be ok or should I consider 5.38's?
 
#33 ·
I have learned that the 07 PCM is a different part number than the 08-09 PCM. I went ahead and got the 08-09 for mine since the transmission is a 2009. But, I've been thinking and I may have to get the 2007 instead for the communication witgh the key system. Does anyone know what changed in the PCM from 07 to the 08-09? Also, could the 08-09 remote start be used with it(referring to the 07)?
 
#36 ·
I'm currently at the dealer about to get my PCM flashed for the tranny swap. It doesn't matter what year the PCM is, all the flashes are the same no matter what part number u have. The way it was explained to me by AEV was that the part numbers change when they make any component changes inside the PCM. It could be something as small as a resistor that could generate a part number change. I'll let you guys know how the tuning goes.
 
#39 ·
I totally understand what your going through with your wife , I got a great deal on my Jeep, but it was an Auto , and everytime I go whelling thats all I keep thinking is man I wish I had a clutch !! Good luck , thats a lot of work and headaches doing that swap !!
 
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