Any issue with putting 4.10 gears in a 2009 Sport differential? Would I need new differential covers?

 

No issues... Unless you got them second hand. 4:10 typically comes in rubicons. If you got them from a rubi owner it will not fit. Your sport has a Dana 30 front, rubi has a 44 front.

If you bought them new, you should be good if your previous ratio is 3:73. If it was higher you'll prob have carrier issues.

 

well I was looking at a used set of 4.10's from a Rubi, so I guess these won't work.

 

Nope, can't stuff d44 gears in that front d30. Also, if you have 3.21's currently, you will want a new carrier for the d30 also. (3.73 and higher, numerically, uses a different carrier than 3.21)


With an auto, you may as well go on up to 5.13's anyway.

 

^That.

It also wouldn't be worth the install costs to add 4.10s to a pre-2012 Sport auto trans. You could run 5.13s with stock tires if you wanted, and you'd like your Jeep a lot more.