2climbbig

My manual tranny is toast!. I have an entire engine assembly (only 50 miles on it) sitting in my garage which includes the brain, engine, auto tranny and all electrical components. The only thing I am missing is the shifter and a tranny cooler.

I am debating whether to buy a used manual or throw in the Auto. I really like my manual but it would be a lot cheaper for me just to throw in the auto. Would love to hear your thoughts on the matter. Has anyone done this swap and am I getting myself into more problems? Is the auto on the 3.8 worth it?

Joe_B

If you swap the auto in are you properly geared to run larger tires?

2climbbig

Good question. I have 4.88s and a super charger so I think I should be fine. I know with the manual I have much more flexibility around that. Do you think I will suffer with 4.88s on 38's if I have an auto?

Joe_B

4.88s and 38s with an auto will suck. I am not too familiar with the superchargers but I would imagine you would want to regear the jeep to run in the engines power band as the super charger and tune are designed around that. Running too low of an RPM might not create the boost needed to feel the effects of the supercharger so you'll still be downshifting all the time to make boost and power. I run 37s with 5.13s and want 5.38s but don't want to deal with the cost of a regear right now. Don't run a supercharger though.

mattgt5

I've been researching SC on the 3.8 and what gears to run. The sprintex guys have told me to try 4.10 on my 37" before I regear. He said 4.88 at most on 37" with their SC. sent from my work leash

2climbbig

That is good to hear. I have a sprintex SC and I do love it. It is great. So, I should be in good shape on the gear. Does anyone know if the exhaust set up is different and is there other mounting points that I need to be aware of?

Invest2m4

It has been done, but a lot of work. Most would say it's cheaper and easier to sell the JK and buy one with an auto trans. Here is a good thread on the process - it should lead you to all the info you need. http://www.jkowners.com/forum/showth...nual+auto+swap

2climbbig

This is a great link. So I have every thing but the cooler and shifted/counsel. The engine, tranny, pcm, and wiring harness is all assembled and intact. Thanks for the link.

I had a friend pull the entire assembly out of his jk when he did a hemi swap. The PCM/ harness is still connected to the engine/tranny. So I am at a much better starting point.

GoldenRubi

just out of curiosity, what exactly happened to your manual?

JDub23

Interested. Been thinking the same thing lately. When I bought my Jeep I wasn't thinking rock crawling. After getting back from Moab this past week, I've noticed the trip was a little easier on those w/ automatics. I've also had a constant issue w/ mine popping out of 1st gear constantly. Last, but certainly not my fav reason, the wife can't drive a stick, and wants to start wheeling also. (This may get me into an LJ, later down the road though - haha)