I recently purchased a manual shift 09 2 door jk X package with 3.21 gears. I do not have to tell anybody that this gear ratio is horrible. I am ready to order 4.88 yukons but will have to save a bit for my lift and 35's. Can anyone see any problems with gearing first?

 

first off how long is a while for the lift and tires? and how much highway driving do you do?

also the speedo will not be off, thats only affected when you change tire size, you would want the aev procal to change your gearing though

 

I normally modify very quick and it is hard for me to drive this jk stock. For some reason my wife is all over me about this one. I have bought 5 procomp 16 inch wheels and body armour rock sliders so far. The stock steel wheels looked like shi$. As far as a time line, I have no clue.

 

I just installed 4.88's in my 6-speed jk and I'm also several months from getting 35's. Right now I have worn 33's(barely bigger than the stock 32 Sahara tires) and I love how it drives compared to the 3.21's. It revs a little high on the interstate, but regular driving is great. Of course off road is way better- not needing 4-lo to crawl nearly as much. I think you should be OK till the new tires.

 

I could be wrong but I thought the speed sensors are on the end of the axles. That extra wire that goes into the end of the axle is for the speed sensor. Therefore, the change of gears will not affect the speedometer but will change the rpm's at a given speed. Changing tire size would affect the speedometer and would require an aftermarket computer recalibration to get it corrected. If you go 35's or larger you are looking at aftermarket programmers. If someone is going to the expense of regearing very few will do less than 35 in. tires.
Note: The dealership will reflash up to the Rubi tires of 32" which would get 33's close enough.