I'm going to do a 3" lift on my xj which i use it to pull a 16 ft. fiberglass boat and was wondering if 31's would be too much for stock gears and towing that. It currently is on 215's and i'm debating on 235's or 31's. thanks

 

I think not. But if you can afford it, why not?

 

What year is the Jeep?

I know that shouldn't matter but I've had mixed experience.

I had a 1993 4.0 AW4 with 3.55's, 3' lift and 31's.

I towed my camper (~1500lbs) 200 miles to a Campground. While the terrain was fairly flat it did OK. Not long after I hit any grades it started feeling sluggish and I started smelling transmission fluid.

Transmission got hot as hell.

Now I have a 99 with the exact same lift, tires, gears, transmission.

I've yet to tow with it but I'm thinking it'll do much better with that.

If you DO decide to tow that way make sure you drive in "3" the whole time. That should help a lot.

Keep a check on transmission temp. If it gets hot while towing I suggest you regear.

 

You should be fine. I would suggest a trans cooler if you don't already have one. I towed a popup camper 1200+ miles on 31's with stock 3.55 gears.

 

It's a 1994. I'm guessing the boat weighs 3k tops, probably less than 2k since i can pickup the tongue and move it around on concrete

 

What year? In drive? How much does your P-up weigh?

Like I said, you might be ok... you might not.

It'll either do fine or the transmission is going to get hot and start puking fluid everywhere.

Transmission cooler and temp gauge is a must, IMO.

 

I'd get a trans cooler, it's cheaper than replacing the trans.

 

92. Sometimes in Drive, I used 3rd while going over the mountain passes or grades. Weight was roughly 2200lbs loaded.

 

Perhaps the use of 3rd is where it's at. I was in drive when the trans got hot.

 

On flat ground Drive was fine for me. Driving over some of the mountain passes in NW Montana required 3rd, and I was lucky to get up to 45mph on some of the 10%+ grades. Mind you this was in August and was in the high 90's.

This was 2 years ago, engine and axles have been replaced since but the trans is still the same.

 

Yeah, this was on some pretty good grades.

Mine did fine on flat ground as well.

Got into the foothills and things got WARM.

 

Well i think i'll be fine, i don't plan on taking it into the mountains, and a transmission cooler is on the list, i've only taken it to a lake 20 miles away and didn't have any problems with the stock setup. Now time to find tires

 

Yup, trans will stay in 3rd and keep the TC locked on grades rather than dropping to 3 and unlocking the TC if you're in D. I even drop to 3 with 35s and 513s for more pep and to keep my trans cool running through the mountains.

 

X2 on transmission cooler and drive in 3.


With that on 31s and 3.55 gears IMO you'd be fine.

I have 3.55s, and 33s and a dana 35 with LSD nonetheless and the towing i've done it's handled fine. I have the factory transmission cooler on my Jeep.