jscribn1

I'm trying to figure out the best gear option for my father in laws setup and we are getting conflicting recommendations. We are re gearing a 2009 Rubicon 2 door. 3.5" lift and we just put 35" tires on it. It's the 3.8 auto trans. and stock 4.10's. Going off the gear graph that I've found online it's a toss up between 4.88's and 5.13's. I say 5.13's would be the best option for his driving style, he tows it behind a motorhome, drives it on the road and wheels it a couple times per month. 4 wheel parts is where we are getting it done and they are telling him 4.88's. Does anyone have any "real" experience with the 2 gear sets I'm looking at? Or someone with recommendations on which way we should go. Thanks in advance for any and all help

nthinuf

Everyone has different wants/needs/uses/locations/etc, so there isn't a one size fits all answer. There are literally thousands of posts asking this question, and the best answer for you is really just to read as many of them as you can. And remember that it's not like one will make it sluggish and the other will give screaming high rpms. We're only talking 120-ish rpm difference at 70mph between the ratios. One common occurence you will see is that MANY people with this weak-ass 3.8 auto will say they should have gone to a higher numeric ratio, very very few have said they wished they had gone lower.

For me, with my 3.8 auto 4door and a front d30, 5.13's was the right choice. When I swapped to a front d44, I went up to 5.38s. I like the slightly higher rpm's, and knew at the time that I would be moving to 37's at some point. For your father, with a 2door 3.8 auto and 35's, either ratio would work perfectly fine, but I think that 5.13's are the better choice. (only a 120 rpm difference...)

BoraBora

I'd go 4.88 if I were you. 5.13's would feel really peppy and fun for sure, but the teeth get realllyyyy small at that point. 4.88 would be a safer bet.

resharp001

You got one vote for 5.13s, 1 vote for 4.88s, and I'm not going to help much cuz I agree with both Bora Bora and nthinuf. If it came down to it though........if he's not out wheelin' it hard, I'd go with 5.13s.......but if he's out wheelin and playing in the rocks, I'd think I start to get more concerned about teeth size as Bora Bora alludes to. That 3.8L needs all the help it can get though......go as low as you feel comfortable.

TheDirtman

I would go 5.13. IF it were a daily driver that didn't wheel and you were in the flat lands 4.88 would likely make more sense just to get slightly better MPG. 4.88 vs 5.13 is a pretty small difference and would not worry about gear strength on a D44. The 3.8 auto needs all the help it can get.

jscribn1

We went with the 5.13's, thanks for all the positive comments.