Motive Gear Part Numbers

I recently discovered a friend's shop is a motive gear dealer. I need to regear my 98 XJ to 4.56. I have a 29 Spline C8.25 rear and HP D30 front. I need to pick up the R&P for both as well as master overhaul kits for both. Can someone help me with which part numbers I will need. So far I believe I will need:

C8.25-456 (4.56 for C8.25)
D30-456F (Dana 30 4.56 Front Reverse Cut)
R8.25RMK (C8.25 Master Overhaul Kit)

Can someone confirm these are the correct part numbers?

Also on Pg. 16 I am not sure which Overhaul kit is the right one for what I need. Can someone tell me which one I need?

http://motivegear.com/pdf/LD_DIFFCAT_011_1.pdf

Re: NEED HELP! Motive Gear Part Numbers

Hopefully someone here can help me clarify which master overhaul kit I need.

sorry can't help you with part numbers but I will say this, go deeper. You can gear to 4.88, I run the same axles as you with yukon 4.88s and 33s... you'll enjoy the power and mpg trust me go deeper then 4.56

XGarfX said:

sorry can't help you with part numbers but I will say this, go deeper. You can gear to 4.88, I run the same axles as you with yukon 4.88s and 33s... you'll enjoy the power and mpg trust me go deeper then 4.56

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What MPG are you getting with 4.88's? Is your speedometer corrected for the tires and gears? NJ has similar terrain and weather to MI so you would be a good indicator for me.

My speedometer had to be corrected with a new speedo gear, you will have to change out the gear to get your speedometer right again. I average 16 mpg mixed driving, I have seen upwards of 21mpg at times though. I was in the same boat as you last year and figured the extra power could be helpful in hilly areas and/or when I'm loaded down with tools and gear for wheeling. You WILL love the power of 4.88s trust me, I test drove an xj with 4.56 before it and that little extra umph of .88 helps out... Plus if you ever wana go to 35s you should still be alright!!

Gear it once and gear it right, go deep.

Whats the speed limit on the highway over in NJ?


Anybody know the part number for the master install kit. Someone has to have ordered a set. Rough Country sends them if you buy a gear package just need the part number off of it.

The speed limit is 55 on most highways here, I've gotten it up to 70-80 on long rides out in PA and it will ride around 3k at that point but for the most part cruising on the highway I'm at 2000-2500 RPM which isn't bad at all. Think less about RPM and more about throttle position for MPG, driving around I'm barely on the gas pedal so that throttle isn't open as much meanwhile my rpms are high enough that I have plenty of power with my tire size.

I think the difference between .56 and .88 is mayb 200 rpms or so but that little bit helps. If you regularly drive 80mph then 4.88 might be to deep, for around town driving and average 55-70 mph highway use 4.88 has done me well and I will for sure miss the power if i step it up to 35s some day.

jsowards said:

I recently discovered a friend's shop is a motive gear dealer. I need to regear my 98 XJ to 4.56. I have a 29 Spline C8.25 rear and HP D30 front. I need to pick up the R&P for both as well as master overhaul kits for both. Can someone help me with which part numbers I will need. So far I believe I will need:

C8.25-456 (4.56 for C8.25)
D30-456F (Dana 30 4.56 Front Reverse Cut)
R8.25RMK (C8.25 Master Overhaul Kit)

Can someone confirm these are the correct part numbers?

Also on Pg. 16 I am not sure which Overhaul kit is the right one for what I need. Can someone tell me which one I need?

http://motivegear.com/pdf/LD_DIFFCAT_011_1.pdf

Click to expand...

I just installed the same gears in my 98. Those are the right part numbers. I dont know about the master overhaul kit though.

TJ STYLE D30IK R30FR R30FRMK
R30FRT* R30FRMKT

despite calling them "TJ" kits, these are the high pinion D30 part numbers-- should be the one you want