Go with the 5.13. You won’t be disappointed. There really is only a 5% difference between the two. Your 8th gear is super tall and you won’t feel high strung at all on the freeway.
I can't tell you the RPM on 4.88 but I found a trick on 5.13. I was playing with the gearing calculator and realized the final gear ratio on 4.10 in 7th gear is identical to the 5.13 in 8th gear on the 3.6 auto. Both have a final gear ratio of 3.44. This assumes all else stays the same after re-gear. So I set the cruse at 70 and 75 mph and manually put it in 7th. That would be my new 8th. If the RPM's are higher than you want, then go 4.88. I was able to get up to 79 mph and 2600 rpm in 7th which felt perfect. And actually where my jeep would be even if I didn't manually put in 7th. I shift into 8th a lot now but any wind or hills will downshift to 7th. I'm not sure I've ever cruised above 80 mph.
Do you feel like your power is too low so you manually put in 7th? wouldnt it drop to 7th if you needed to pass? Thank you for your answer as I'm debating the two gears as well.
I only put in 7th manually with my stock gears to have a feeling where the RPMs would be when I re-gear. I was debating between 4.88 and 5.13. Everyone recommends the 5.13 with 37s but I was afraid the RPM would be too high on the interstate. To see if it was, I manually put it in 7th which would be my new 8th. I drove that way for about 30 minutes. RPMs were not screaming at 2400-2600. I had plenty of power. Now with it in manual, I don't know what the auto will do with 5.13s. At 2400 RPMs I can't imagine it will downshift a lot. I'm sure if you punch it, it will drop to 5th or 6th. But I had plenty of power in that rpm range.
I've seen pinion size debated on here and on there. Every single shop or person I've talked to says its not significant enough to base your decision on. Local shops, northridge, JK Gear on YouTube, I think Yukon talks about it... Supposedly what matters is the surface area of the tooth and not the actual pinion size. Just what I've been told by actual people that install them regularly. FWIWFound this chart last night on the JT forums. Now I’m more worried about pinion size 4.88 vs 5.13 leaning towards 4.88 since it should work with 38’s and slightly bigger pinion size also is a plus.
True!
Exactly! The difference is so little. The margin of failure between 4.88 and 5.13 is so small that if something were to damage the 5.13 pinion, it would likely damage the 4.88 pinion (or ring gear). Anyone who damage the 5.13 gears would have likely damaged 4.88 gears.
I can't wait to go to 5.13 gears. I can already get out and walk next to the Jeep with the 6 speed in 4lo with 4.10's. 5.13's will be insane crawling ability.
Even though I like the 5.13 gears, sometimes I even wish I had deeper gearing - even with the 4.1 transfer case. I guess that's where the Atlas transfer case would come in...if I really needed it. But I don't.
haha. Good decisions are dumb. oh man. that's awesome. I'm jealous. Is the UD44 plug and play with the locker? or do you have to do more? I bet you'll like the 4.88. Local shop told me you can't go wrong either way. Especially from the 3.43 or whatever is in the sahara. I really don't hate my 4.10 with 37's which is why I think 4.88 might not be horrible at all.
I think my wife would hurt me if I went even taller, though she does like the ride of the 37s. The UD44 is plug and play, supposedly. I'm just going to use one of my Aux switches since I don't have the factory locker switches, plus I won't have the rear locked yet anyway.
