I have 33 tires, and 4.1 differential gears.
Bought the XJ for offroad camping, and some rocking, but that offroading may require 400 to 1000 miles highway driving just to do 50 to 200 miles of off roading. prior owner put in 4.1 gears when he had 31 inch tires, but later put on 33 inch tires.
I do have a very low range transfer case, at 4.1 in low (Atlas 2) so off roading in Low transfer case with 4.1 differentials is still pretty nice because of the transfer case low range gear being a lot lower than a stock transfer case.
On highway, on the flats, it cruises ok, but does need to down shift on hills, even moderate hills to maintain a decent speed. I travel with a fellow Cherokee friend, he has my same differential gearing on smaller 31 inch Tires. He can out pace me on the highway hills.
he also has the later 2001 H.O. motor, where as I have the weaker 1990 Renix motor.
On moderate grades I am usually a gear lower than him ie he may still be in 4th, while my tranny (AW 4 Auto) is in 3rd, so ineffect my rpms are higher on hills, of course on the flats, or with a stiff tailwind, both our Xjs at 70 mph In fourth gear, my rpms are lower than his, but he is oft better in the power band for passing.
Now with a stock transfer case gearing, I have not driven one with 33 tires and 4.1 differentials much less one using low 4wd, but I would heed the info by others, your crawling ability may be reduced, Low 4 in first gear will not be so low with that 4.1 differential and a stock transfer case, and if you rock crawl, or do mega steep offroad, you probably will notice a difference, but with an automatic tranny, you do have a bit of leeway, as the torque converter can slip more to a point to make up for gearing. using torque converter slip to get that lower in effect gearing does heat up the ATF fluid in the tranny, so dont try that all day long on a long steep crawling type road, but for a short section, with a good tranny cooler set up, you can do this without harming the tranny. If you have a manual tranny, forget it, clutch slipping is not a viable option!
So yeah, 4.1 differential gearing is kind of fine on long relatively flat high speed highways, with little need for passing acceleration. but you do end up in 3rd or even 2nd on some highways on grades.
The later bigger power engines probably are less effected than early motored XJs
Your driving style too is a factor on highway, if youre an aggressive, get there fast type, the 4.1 is not as nice, if you dont mind slowing a bit up hill, but making it up on the down hill, and dont try to be the fastest vehicle on the road and pass others, then the 4.1 is fine on the highway
My old ride was a VW Vanagon, flat four maybe 95 to 100 Hp, (I upped displacement from 2.1 to 2.2 liter), and we took it on many a road trips, mountain camping etc.. It was slow, it is a different driving mindset, and I enjoyed it despite being passed by loaded semitrucks on highway 80 in the California Sierra, climbing neary10,000 feet.
My 33 inch tired, 4.1 differential geared, early Renix motored XJ is slow, but not near as slow as that old VW Vanagon.
Now I could tell you about how slow my 63 VW Split Window Microbus fitted with a 1961 1200cc Bug motor was when going into the high Sierra for back packing back in my youthful school days. How slow? That was get out and walk speed on some grades, Literally! and the worn tranny would pop out of first under load, so I had to keep one hand on the stick shift to hold it in gear up highway 80 heading towards Donner, or highway 120 over Tioga Pass. that 1200cc motor was rated as 40 Hp, but it was tired, and at 9000 feet was probably only producing half that 40 Hp!
Anyway, that is my two cents.
Now if you habe a stock