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Move up to 4.10 or 3.73 on 235s?

The comments about just needing new shafts to go 29 spline in the 8.25 are correct.

My 01 XJ has run over 300,000 miles on BFG A/T 235/75R15 with the stock axle gearing and I never considered changing the gear ratio.

When I installed lockers in my 97 XJ which runs BFG A/T 30x9" I went with 3.73 because I didn't want to buy a 3.55 locker for the front D30. On that Jeep going 4.10's may have been a better idea.

Incidentally, my 97 XJ came with the UpCountry package and it had 3.55 axles.

Both Jeeps are automatic transmission.
 
I wouldn't do any of this for a negligible gain in gearing

If you're going to do it, at least go 4.56

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I've been trying to find proof a pair of these were ever made for about 10 years. I've managed to find the alleged south american HP44 front, japanese right hand drives XJ's, factory 4.56 4 cylinder XJ's.

But I've never found an up country / tow package 3.73 XJ.

Same here. My 98 had a factory installed hitch and came with 3.55s.

XJ axles with 3.73 factory installed do exist in the parts catalog. I've just never ever seen them nor have I been able to find when they would be optioned.

Some ( actually very few ) early 1980's AMC XJ's were built with the optional 3.73 gears. As a cost control measure, Chrysler eliminated the 3.73 and 4.56 gears shortly after buying Jeep in 1987. I have not seen an early 1980's XJ in the junkyard in many years.

I thought it was the 3.30s they got rid of, and the 4.56s when they ditched the 4 speed aw4 2.5L option and went back to the 3spd Chrysler trans previously used 86 down because it was one of their products, which would mean you'd want 3.55s again. I could be wrong.
 
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I wouldn't do any of this for a negligible gain in gearing

If you're going to do it, at least go 4.56

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That would spin up the 4.0 to high for any practical use.
 
4.56 with an auto and 235s would be... 3000rpm at 75 in overdrive. I dunno, it'll eat more gas but that's not too bad really.
 
James drove on 4.56 and 235's with an ax-15 for 2 years before we finally lifted him.

I can't say that it hurt his mileage at all.
 
James drove on 4.56 and 235's with an ax-15 for 2 years before we finally lifted him.

I can't say that it hurt his mileage at all.
Efficient use of torque can't be a bad thing

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