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Fire App. Mech.
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Discussion Starter #1
Hi, I am kicking around a spec for a new truck and I want to get some info if I may.

Truck will be a KW T300 for propane delivery. Right now we have them with 330 HP ISCs and 5.38 (I think) rear ratio with Allison 3000 RDS transmissions. Top gear ratio is .65 and tires are 10/22.5 which I think gives 505 revs/mile. This gives an engine RPM of about 1600 when cruising at 63 mph. They strain a fair bit when manuvering in close quarters and we rarely ever go that fast.

I'd like to go to an axle ratio of 6.14 or whatever the actual number is. This will give an RPM of around 2000 at 63 mph. We already have one with a direct drive Fuller transmission and it does fine at this RPM and speed.

My question is would the drive shaft ratio be within Allison and KW's allowable spec and would it be a good idea? The Cummins Powerspec calculator seems to indicate that there is no axle ratio "in between". From memory I think we have Spicer S170-210 axles. Do they make a Rockwell/Meritor option in this truck? Locking diff is a must have.

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