I have a 1991 XJ with a 5 speed AX-15 tranny and a Dana 35 rear axle. I understand that if I want to upgrade the rear axle to a C8.25, it has to be a 1997 and up ? and also, does the C8.25 have to be the same gear ratio and the Dana 35 ? and how do I determine the ratio in my D35 and when I am picking a C8.25 from the JY? thanks guys for the input.

 

Which engine do you have?And yes your front and rear diffs have to have the same gear ratio in them for the 4x4 to work.If its 2wd then it kinda don't matter to a point.

 

I think all the ones with an AX15 trans had 4.10 gears I know the newer ones with the same trans and a Chy 8.25 were 4.10's.


You must know what is in the D35 to be sure that someone had not changed them at sometime front and rear must be matched.

 

I have the 4.0 6 cyl. What ever the gear ratio is it is perfect. And I want to find a 8.25 that is the same as my D35. How do I determine the ratio of the D35 ? Thanks. And yes it is 4x4 D30 up front and D35 in the back. Also will the U joust bolt up to the yoke of the 8.25 ? I have the 3110 joint I think. Thanks.

 

There is a plate on the diff cover sitting between two bolts.

 

Not sure how true this is
Jeep XJs came in several standard gearing ratios:

• 3.07:1, manual transmission, I6 engine.
• 3.54:1, automatic transmission, I6 engine with Dana 44 rear differential
• 3.54:1, manual transmission, I4 engine with Dana 35 rear differential
• 3.55:1, automatic transmission, I6, V6 engines; manual transmission, I4 engine
• 3.73:1, automatic transmission, I6, tow package, UpCountry package, 2.5 VM diesel manual
• 4.10:1, 2.5L I4 engine, V6 manual transmission
• 4.56:1, automatic transmission, I4, offroad or tow package

 

I was off base on that one for sure sorry.

 

Thanks fred NA0ZZ, for the advice. also I am a HAM also...AA7KN....Tanks again

 

Great I will check my logs to see if I have worked you before have quite a few contacts there in the past.


73's