kevin__jeep

So I've been doing a lot of reading on this and can only find a few opinions/reviews of running 31s with a 5-speed through the stock (3.07) differential.

I've seen many say that running 31s on the 3.55 with the auto isn't a big deal, but have heard a few times that it can really make the 5-speed a dog.

Currently I'm on 30s, but they are worn, and it rides well/quick enough for me. I don't really want to swap in 3.55 axles, I'm more interested in what it would be like with the stock differential

Can I get some more thoughts on this from you all?

5-Speed

I daily drove my last one for 3 years with the 31s and 307s. It worked but was a turd. My current XJ I went with 31s and 373s. Love it! I think its worth doing the swap.

investinwaffles

Actually getting gears installed tomorrow - I have 3.07's with 33" tires and it is survivable, but miserable. Going up to 4.56

Sometimes I get stuck in 3rd going up because 4th is too low to hold RPM, and in 3rd I cant accelerate so I am literally stuck at a certain speed and if someone slows down infront of me I am screwed. But that's in the Colorado mountains, on the highway I don't really drive that aggressively and can still cruise at whatever speed I want. Acceleration is severely lacking though, wont even get out of its own way

You can use this calculator to ballpark what RPM you will be turning with 31's
http://www.grimmjeeper.com/gears.html

3.55 axle swaps would be the best budget option without a doubt

DExj1288

I had 3.07's with a 5 speed and 31's. Ran it that way for about a year. Its not bad. I live in a really flat area, so hills weren't really a concern though. My biggest problem with that setup was that first gear is pretty much useless. As soon as you get rolling you're grabbing second. It's doable though. Even had it in soft sand often and it did ok. Just used 4 low and started in second.


With that said i did just finish swapping in a set of axles from an auto xj and the 3.55's make a noticeable difference. Definitley worth the swap.

s14unimog

3.07 and 31's aren't that bad at all. I ran that for years without an issue. Currently I'm running 3.55's on 33's and even that's not bad. I guess it depends on how you like or don't like to rev out your truck.

Gezus man... planning on 37's?

Martlor13

i had 3.55 on 33s and it was garbage imo. Overworked the trans big time

investinwaffles

4.56 and 33's is perfect with the 5-speed manual IMO

I actually went for 4.88's at the last minute and am already shopping for 35's, but have about 10k miles left of tread at least. If I can find a good condition set on Craigslist, I might buy em and put up the 33's for sale since they are in good shape

Automatic trans I have no idea about