Regear Question (yes I've read through the forums)

[Gren71]

Like I said..ive read through the forums and a mess of threads..watched a bunch of videos...and so on. Im still by no means an expert here.

I can't seem to find a consensus on what is worthwhile for a JTMT with daily driving..a LOT of opinions. So I am looking for more opinion I suppose.

I have a JTMT and use it for %90 daily driving, some beach, and towing a travel trailer that weighs 6,000ish loaded. 285/75/17 AT tires..I MAY go to 315s at some point, but not likely. Im pretty content with my current size and weight. I see 8th while driving on the highway, but only after a recent TCM update from my dealer. I can pull my unloaded trailer okay (4,500lbs), but the JTMT still seems to struggle a bit with towing. My goal is to get a little more time in 8th with daily driving and have an easier experience towing.

Im pretty sure Im going to do 4.56s. From what Ive read they will keep me near my current RPM range but allow me more time in 8th during normal driving, and give me more power while towing.

I have a local jeep guy who will be doing the work for me so the cost should be comparable to many others on the forum.

Am I completely wrong here?

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[KurtP]

I think 4.56 with that load and trailer is right on the money. I’d give some thought to if you will step up to 315/35’s; because if you do, 4.88 might be where you want to end up with all that.

$.02

 

[CivilJeep]

Like I said..ive read through the forums and a mess of threads..watched a bunch of videos...and so on. Im still by no means an expert here.

I can't seem to find a consensus on what is worthwhile for a JTMT with daily driving..a LOT of opinions. So I am looking for more opinion I suppose.

I have a JTMT and use it for %90 daily driving, some beach, and towing a travel trailer that weighs 6,000ish loaded. 285/75/17 AT tires..I MAY go to 315s at some point, but not likely. Im pretty content with my current size and weight. I see 8th while driving on the highway, but only after a recent TCM update from my dealer. I can pull my unloaded trailer okay (4,500lbs), but the JTMT still seems to struggle a bit with towing. My goal is to get a little more time in 8th with daily driving and have an easier experience towing.

Im pretty sure Im going to do 4.56s. From what Ive read they will keep me near my current RPM range but allow me more time in 8th during normal driving, and give me more power while towing.

I have a local jeep guy who will be doing the work for me so the cost should be comparable to many others on the forum.

Am I completely wrong here?

I have found this website to be a great resource for these kinds of questions;

Gear Ratio Calculator (tiresize.com)

Like you, I think about what I want to do to my JT, and I like hearing opinions. This tool can help put some data with those opinions. If you're like me, testing different tire sizes and gear ratios is a fun exercise, and this calculator will help you see how different scenarios will play out.

 

[LostWoods]

Sorry typed something out thinking JTMT meant manual trans...

IMO, there's no reason not to do 4.88s on a Max Tow running a 33-35" tire. 8th is so deep an OD that you aren't going to see any appreciable MPG hit and the shorter gears will let you spend more time in OD.

For reference, 5.13s are the same as losing 8th altogether. 4.56 will be very similar to stock on those tires and 4.88 will give you just a little extra grunt. Personally, I always felt it needed a little extra on the bottom end and with how often it was in and out of 8th even with the stock tires, 4.88 feels like a no-brainer.

 

[AmishMike]

I have the stock Rubi with 4:10's and am on 315/35's Pulling a 4,000lb trailer without any problem. I feel like 4.56's would be nearly perfect but there is no reason not to go 4.88's with the deep OD in the A/T. Again, the Rubi has a lower transfer case so crawling around is fine.
If I were to make the change from 4.10's, I would go right to 4.88's
(I have run 5.13's with 30.5" tires, spool, and no OD with a big block on the street so......)

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