ckmehl

what are the stock spine's on the 2008 X? or do i need to worry about the spline count when doing new gears. this is new for me. if i want to run 35's. gears would be helpful. but if i only run 33's how would 4.88 or 5.13 perform?

RedneckJeep

Splines on what? There are splines on the pinion gears, splines on the insides of the rear axles, splines on the inside and outside of the front axles, splines on the steering shaft, splines on the driveshaft. Like my 11th grade English teacher used to tell me........"Be moe pacific!!"

ckmehl

if i'm changeing out gear's that would be a pinion gear. if worng please let me know. new to this stuff!

ckmehl

thank you for the chart. at least that gives a little to base the power from. 4.88 is the gear set. now just need to know what the spline count is on the pinion gear for a stock D30 and D44 on a "X".

nthinuf

I believe the Dana 30 front is 27 spline, the non-rubi Dana 44 rear is 30 spline. And the Rubi 44's are 32 spline?

But...

Call this guy from you sig
Tell him what gears you have now, he'll let you know if you need a new carrier or anything like that as well.

Folks here generally find that 35's and 4.88's are good for a manual. 35's and 5.13's are good for autos. My opinion, if you're even considering 35's, gear for them now even if you're staying with 33's for a while. You don't want to regear twice.

Stuka

Since JK gears only work in a JK, all you need to know is if its an X/Sahara or a Rubicon. No other D30 or D44 gears will work in a JK.

As for how it would drive with 33's and 4.88's or 5.13's... Slowly would be the best way of putting it. Accelleration would be awesome, but your top speed will be RPM limited. If you don't mind cruising at 3000rpm, then you will be able to go 70mph. Just don't expect any sort of decent fuel economy.

BlackNorthernJK

are you getting confused with spline count for the carrier and axles? 'cause as mentioned above you don't need to worry about pinion gear spline count, you'll need JK specific ring and pinion...so...you shouldn't need to worry about that...unless your changing carriers or putting lockers or LSD's in
and if your simply doing a re-gear, so long as you have JK specific gears your fine.
And in case your wondering, your D30 front gears are reverse cut...also if your changing from a 3.21 to numerically higher you'll need a new carrier up there...

ckmehl

i have 3.73. so if i do a rear locker i have to worry about the spline count?

BlackNorthernJK

Yes, unless you plan on changing your axles as well.
I see you have an '08 X, as you already are aware you have 3.73 gearing front and rear. This means that your rear axle spline count is 30...meaning if you plan on using stock axles and upgrading locker, lsd or whatever only, you will require one that states it is for a Dana 44 3.73 and numerically lower ratio with a 30 spline count to accept the axles. 3.73 and lower because our JK Dana 44's use thick ring gears, so even though you are putting a 3.73 and numerically higher gear ratio in you still need the 3.73 and numerically lower locker. Make sense?

ckmehl

so let me see if i have this now. changeing my gears out 5.13's front and rear. when i put in the locker in the rear the ARB JK 30 spline Dana 44 & all gear ratio's will work with no problems. and yes i will be doing the ARB air system.

is there anything else i need to know about doing this. i will not be doing the installation. paying a professional to do it. i did not realize that the JK has a specific gear. Thank you for that little tid bit. that makes things much easier.