Gearing question
- Thread starter AndyG
- Start date
At the end of the day, every transmission, gear, and tire combo is going to drive different. It even makes a huge difference if you have a 4 or 6 cylinder. The ONLY way to know what gears you should run is to look at what people who are knowledgeable (the chart is an awesome example and is compiled by those who know) are running with the specific transmission and specific tire size. Often blanket statements are made about “automatic needs this” “manual needs this” but there is a huge difference between each one. The chart above takes into account each of those differences and is backed by real world experience. I could have taken my Jeep to 4 different shops that said “put 4.88s in for those 35s” and not only would they be stupidly wrong, I would have been unhappy. I’m much more happy cruising the highway at 2700-2800 on 5.38s and 35s
I can easily see that... 4: 10 would be the most and the vehicle I drove is not suffering with 3:55 especially with a tire that is not too meaty.
Based on my other two I would have a hard time justifying the expense of a regear to 4:10.... That jeep I drove is in the hunt as it is.
That’s what it comes down to. If I had 5.13s and the reccomended is 5.38 - I’m not paying $1200 to regear. Now a larger difference makes the price okay.
42rle / 29.5" /3.73 = 2052rpm @ 70mph
NV3550/29.5"/3.73 = 2320rpm @ 70mph (nearly 300rpm higher than the 42rle)
AX-15 / 29.5" /3.73 = 2349rpm @ 70mph (nearly 300rpm higher than the 42rle)
NSG370/29.5"/3.73 = 2498rpm @ 70mph (over 400rpm higher than the 42rle)
32rh / 29.5" / 3.73 = 2974rpm @ 70mph (nearly 900rpms higher than the 42rle)
NV3550/29.5"/3.73 = 2320rpm @ 70mph (nearly 300rpm higher than the 42rle)
AX-15 / 29.5" /3.73 = 2349rpm @ 70mph (nearly 300rpm higher than the 42rle)
NSG370/29.5"/3.73 = 2498rpm @ 70mph (over 400rpm higher than the 42rle)
32rh / 29.5" / 3.73 = 2974rpm @ 70mph (nearly 900rpms higher than the 42rle)
The 42LE was modified in 2003 as the 42RLE, originally for the then-new Jeep Liberty. It is a 42LE transaxle, modified for use in rear-wheel drivevehicles by removing the integral differential and transfer chain. Power flow exits the rear of the transmission. The case has also been modified. By design, it has full-electronic shift control with adaptive memory to learn the operator's driving habits controlled by the vehicle's Transmission Control Module (TCM). Contained within the automatic's torque converter is an Electronically Modulated Converter Clutch (EMCC), designed act as a shock absorber for harsh shifting. 42RLE production ceased in early 2012.
It never belonged in a TJ, that’s for sure.
When I went to 4:56 it was worth it but I wouldn't spend that much more to go to 4:88... At the same time if I had it to do over again I would probably just go to 4:88.
I do agree with the statement if the numbers are close... Go ahead and go with the higher.
Ya the chart is great and now I understand it more. I always listen to people with experience or have done it before because they can give you the insite of what did or didn’t work for them..I was struggling with this gear thing though.. but now I can rest
I see a trend
It’s almost like they are all better ratios than the 42rle. Here is one but benefit of the 42rle and it’s 0.69 OD that most overlook. Having 5.38s makes it perfect on the highway. But if Josh did the same thing above with first gear rather than final - you’d see that gearing it that low makes it an absolute BEAST at crawling - with no compromise at highway speed. And of course, I can get a rubicrawler 
I almost understood what you saidI see a trend
If you guys can... Get this guy to post a picture of his TJ Now vs. Last fall.Ya the chart is great and now I understand it more. I always listen to people with experience or have done it before because they can give you the insite of what did or didn’t work for them..I was struggling with this gear thing though.. but now I can rest
He has got a substantial build going... And it is so cool the way he does it ... He just keeps his eyes open and if he sees a deal he moves and if it works out great and if it doesn't he just keeps on looking... He does everything he can himself... He knows exactly when to turn something over to a shop... Barters and horse trades little bit. And basically just doesn't do stupid stuff with his money.
We met through the forum ... I live in North Alabama... I will drive down to his lake house or over to Georgia to give him a hand in a heartbeat. Very cool guy.
Sounds like my kind of guy! You have to make a build thread @Hog - we are all addicted to tj pics on here
plus I’d love to offer advice and help.
No I’m good.. I’m completely happy with what I’ve learned for now, @AndyG and I were discussing going to Moab next year and I was concerned with ratio and told him I didn’t want to show up with 3:55 when everyone talks about 4:88 and 5:13 and such.. I kept thinking I was missing something and we did the tire spin and watched the shaft spin to see perhaps PO may have changed gears causes mine will go( for a Jeep) til u let off the long pedal. But now I know whom to ask if I have more questions.. ThxFire away with any questions! No promises, but I’m sure I can break it down
No problem man. Next time you clean out of the diff you can always count the number of teeth on the ring gear and I’ll tell ya what you’re running. Or if you have an exact rpm, speed, and tire size on the highway I can tell you right now.No I’m good.. I’m completely happy with what I’ve learned for now, @AndyG and I were discussing going to Moab next year and I was concerned with ratio and told him I didn’t want to show up with 3:55 when everyone talks about 4:88 and 5:13 and such.. I kept thinking I was missing something and we did the tire spin and watched the shaft spin to see perhaps PO may have changed gears causes mine will go( for a Jeep) til u let off the long pedal. But now I know whom to ask if I have more questions.. Thx
I didn’t do very good job of logging stuff, or taking pics.. it just kind of happens and poof, she looks different.. @DrDmoney and @Alex01 talked me Into some Frenched (not sure what you call them) taillights that I have to cut a hole in the tail end, but I’ve seen y’all’s build threads and mine would have a lot more cussing and slinging wrenches then cool and detailed pics.. I’ll post a couple here thoughSounds like my kind of guy! You have to make a build thread @Hog - we are all addicted to tj pics on here
first bought it
2nd is with @AndyG
3rd is stripped wheels
4th is lifted
5th is bronzed wheels and smaller flares
Jks trackbar zj tie rods and Moog ends
Let's retake that picture when we go back this August.
That is definitely something i wanna do is change the diff oil!!
That is awesome bother! Well done mods that look great. It’s amazing how much better it looks with the smaller flares.
Yes thank you.. I liked the flares they were the 6.25” ones but I am much happier with the smaller ones
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