I drove my XJ (4L, AW4) several years on stock diff gears with 31" tires that were closer to 30" tires. I found that I mostly drove around in 3rd gear. The only exception was driving faster than 60 mph on the freeway. That only real issue was driving at 40-45 mph on inclines. The motor would either dog along in 3rd gear with the TC locked, dog a bit less with the TC unlocked, or it would scream in 2nd gear.

This summer, I finally upgraded to true 32" tires (265/75-16), and for about a month, I continued to drive on stock gears while I made plans for regearing. It was pretty bad. Driving around in 3rd gear pretty much was not working any more. The TC was always unlocked, and it dogged badly going up any hills due to the poor gearing.

Finally got 4:10 gears installed which puts the overall gearing at 2-3% lower gearing (engine spinning 2-3% faster compared to stock for a given vehicle speed) compared to stock 3.55 gears and stock size tires. Its so much better for around-town and highway driving. I've found that its still optimal to drive around town in 3rd gear because the TC will lock in 3rd gear (whereas when AW4 is in D, the TC will not lock in 3rd gear). Engine rpms are now in a useable range for daily driving, and the TC locks much more frequently which will help gas mileage.

I can't imagine driving an XJ with 33" tires and stock gears. It would be horrible.

 

Good review.

I have a stock 8.25 with 29 spines on 33"s - might need to upgrade to 4:10 as well. Who made your gears?

 

The shop that did the install recommended Revolution. Seems to be one of the better brands, so I went with it. The front makes a little more whine than with the stock 3.55 R&P (I have an NP242 so I can drive it on the street in 4FT). The shop said that's to be expected with with these gears. No idea if that's correct.

 

Right on, glad the 4.10s worked out. It's a night and day difference, isn't it? Stock gears on 33s is absolutely miserable, you're just riding the torque converter all the time. Good call sticking with 3rd around town to get that lockup.

 

Yes, much better. I do wonder a bit how it would drive with 4.55s. The motor would be spinning at 2700 rpm at 73 mph (my typical speed in a 65 mph zone) which is a little higher than I would like, but otherwise I think it would have been pretty good.

 

I've got the Yukon 4.56s with 33s...Takes off out of the hole like a rocket..lol....And I do 70-80 all the time and don't really notice much difference..Meaning it doesn't seem overspun on the highway..And I still get 15+mpg average...

 

I just finished 4.10 regear with revolution gears on my 94 with 31” milestars, it’s peppier, and it doesn’t hunt gears like it did before in the mountains. Fuel mileage seems about the same if not a little better. Quiet as can be. No gear noise. Just have a noisy truetrac in the rear. Little bit clunky on deceleration when it comes to a stop. Think I’m gonna run a ox locker like I did in the front.

 

I've been driving on 31 inch tires with 5.13 gears for the last month or so. Its comically low, but not undriveable. It shifts out of 1st gear almost immediately upon acceleration, and I am in overdrive at about 33 mph. Obviously RPMs are way high and I can't comfortably cruise at more than about 65 mph, but its been fine for secondary roads while I'm working on some other stuff.

 

Out of my three,
The 33's with 4.10 gears and aw4 feels almost stock. Shifts as expected and feels strong till 90+
The 33's with 3.55 gears and ax15 is a little slow. Slow off the line, comes alive at high rpm, bad at hills.
The 235/75/15 with 4.10 gears and aw4 rips until 65 or so, then you realize its an off highway package for a reason.

 

My rear Trutrac clunked after the first shop installed it with stock diff gears. There is no clunking after I had a different (probably more experienced) shop perform the 4.10 gear install.

 

I was going to say it might not be the trutrac... I've got them front and rear with never any strange clunking during highway or off roading...

 

i got 33 tires and 4.11 gears, hate it, I plan to upgrade to 4.56 or 4.88 my jeep is heavy with gear, bumpers winch, roof rack, big bumpers, rails, stiffeners. on steep highway upgrades it is a dog with 4.11. go with 4.56 gears but if you is heavy, have mountain roads to climb, consider 4.88 this also give you margin for slightly bigger tires I have the AW4 auto. my transfer case is an Atlas 4.1 ratio low range

The pre 1991 xj with AW 4 has a different fourth gear than post 1990 AW 4 xj. the early fourth gear is a lower ratio, so it needs to down shift sooner from 4th than the later AW 4 when going up hills, or when punching it to pass in fourth.

 

I agree 456 would be a better all around driver. If future plan for 35s then 4.88 is your only option.

I did 4.88 have not regretted it on 33s or 35s.. just now wish i could do 5.27s

 

I got 4.11 gears with 33 inch tires, (prior owner did the 4.11 when he had 30 inch tires) The 4.11 is miserable with 33 inch tires. I will soon be regearing, torn between 4.56 and 4.88 I am leaning towards the 4.88 With the 4.11 it will need to down shift a LOT on up hill highways, down shifting to 2nd gear!!!! And means you are really limited in top speed up hill. Even minor freeway up hills cause my jeep to down shift to 3rd, but int he mountains, ugh, 2nd gear with 4.11 and 33 inch tires. The 4.11 is ok for 30 inch tires unless you are heavy loaded, or not going up steep mountain highways.

consider too if your jeep is heavy, add off road bumpers, winch, rockrails, a bunch of camping gear, spare gas, tools, or you tow something and you will soon find how wimpy the 4.0 liter 6 is.


for 33 inch tires you will be MUCH better off with a 4.56 gear or 4.88 4.88 also give you ability to upgrade to even larger tires if you think the engine rpms is too high.

Plan ahead, consider added weight, consider steep up highway hills, consider future want for bigger tires. 4.11 is just not very good for 33 inch tires, even when I am not loaded for camping, slight freeway uphills cause down shifting to 3rd.

I cant wait to regear as it will make my jeep much more drivable, and faster, just is I hate the process, regearing is a pain, a bunch of work. I already replaced a water damaged front gear right after purchase, I wish I had known better and did the 4.88 conversion, but I didnt know better then. We did the regear in my buddies jeep, first to 4.11, from stock then to 4.88, so that was twice in his jeep to get it right.

the 4.88 will give you better off road ability also than the 4.11

4.11 is just ok for 30 inch, but not good for 33 inch.

 

I’ve been pretty happy with the 4.11 on 31” tires, even running a little heavy with bumpers, skid plates, gear, etc.

I do have a bit of regret though, as I may want to go with bigger tires now, which would mean another re-gear.