JE8154

output shaft on a 5 speed auto transmission is different from the output on the 4speed auto or the 6 speed manual. I believe the 5 speed auto is much larger.

Invest2m4

Yep, sounds right!

BucYouUp68

What are the benefits of the swap?

Tooadvanced

Lower gearing for better control in technical offroad driving

Invest2m4

^^^exactly what he said. I've swapped everything on my JK, have lockers, etc. However, the t-case swap was hands down the best mod I ever did. It was also one of the first mods I did. It took one good wheeling trip to realize how much I needed more low range. If you have a manual trans like me, it makes downhill driving awesome. Also, no need to clutch climbing rocks, the engine will idle over most obstacles. In fact, I am running 4.88 gears with 37s, on flat ground, I can't stall while hitting the brake (maybe if I jammed it to the floor I could, but you get the point). If I had to choose between lockers and the t-case, it would be the t-case hands down. I rarely use my lockers. Pick a good line and it is easier to run open.

BucYouUp68

This is great info, Thanks

Matthewd5

I'm also running 37's on 5.13, it's already super low when in 4 lo, it seems like I wouldn't want to be lower... I must be missing something

Offroad_Elements

The Rubicon transfer case is night and day, especially with a 6 speed... Crawl ratio on the rocks is much more enjoyable.

Roryslife

I also put a rubi t-case into my 12 sport manual. By far the best mod I made as far as bang for buck while offroad on rocks. I have 4.88 and 37s and to tell the truth, Id prefer even lower.

May go to an Atlas 4 some day.

jsj4raiders

I agree, the 4:1 swap is the best thing ive done do my jeep to improve rock crawling. I have 2007 2dr, 4.88 with 35's, 6 speed and just took it out couple weeks ago. It makes crawling so much easier. Much less stalling and smoother climbing. Good to have a friend to help. I hurt my shoulder pressing it up at awkward angle just to size up the fit.