Re gear 3.42 to 3.90 or 4.11?

ODPX15 · Mar 10, 2026

Ok , im leaning towards 3.70 , but thx for feedback.

rollin coal · Mar 10, 2026

ODPX15 said: ↑

Hey everyone, I have a 2019 international LT that I purchased last year for dump truck work.

Truck has Cummins X15 , 500 hp , 1850 torque engine from factory , 10 speed manual trans rated at 1850 torque and 3.42 gear ratio with 11r22.5 rubber.

Im running the truck in Midwestern Illinois, specifically the Illinois Valley area by I80 / I39 area.

I notice the truck struggles somewhat on inclines , what gear ratio would work better 3.90 or 4.11 ? The reason im inquiring about those is because I've driven the brokers 2002 KW with C15 / 13 spd and 3.70 gears and it also struggles somewhat .

My final gear ratio with 10 spd on my truck is .16 , thoughts ? Also what am I looking at cost roughly? And how much will one of these ratios help my operation? TIA.
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Sounds like a lack of maintenance issue with the 2002. I had the exact same engine, trans and rears with 11R 22.5 rubber in a 2003 KW and never struggled on any inclines.

Can't help you with the X15 it's probably just how things are with that particular engine. Never seen anything post 2008 that really had any sort of get up and go. Re-gearing it would be a massive waste of money and time. Those gears it's got are probably right. Like was pointed out going from tall rubber to low pro would be equivalent of putting slightly higher ratio / lower gearing in it.

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Re gear 3.42 to 3.90 or 4.11?

ODPX15 Bobtail Member

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Re gear 3.42 to 3.90 or 4.11?

ODPX15 Bobtail Member

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rollin coal Road Train Member

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