Posted by dave in Plano, TX on Friday, August 25, 2006 at 1:26PM :
In Reply to: LET ME re-OPEN this topic (WC 3/4 ton speeds) posted by dave in Plano, TX on Friday, August 25, 2006 at 1:22PM :
"On Road Gearing for your Dodge
Chances are your vintage military or civilian Power Wagon has the stock 5.83 ring and pinion gears. This ratio was chosen for tactical vehicles to best suit their primary off road function and was generally carried over to post war civilian power wagons. Chrysler did offer a 4.89 option on some Power Wagons, but few were ordered due to their heavy work requirements.
Today, for the majority of trucks driven primarily on paved roads, the stock gearing is inadequate and destructive. The 5.83 gears with 900-16 tires yield 43 MPH at 2500 RPM, the healthy maximum for the Chrysler flathead. Sustained operation above that, particularly at the light to moderate load imposed by the tall gearing, leads to premature bearing failure in the long stroke flathead. The high drive train speed directly effects the transfer case since 2WD power is transmitted through the transfer gears, generating excessive heat, noise, and wear. High speed of the unbalanced driveshafts causes vibration leading to worn universal and slip joints. Re-powered trucks with the tall gearing suffer additionally; the added power is not proportionally harnessed and the increased RPM further aggravates the overworked drive train.
With 4.89 gearing your Dodge will drive nicely at 52 MPH, a 20% increase at the same engine and drive train speed. You will experience smoother, quieter, and more efficient operation since the engine is operating in its peak power range and the drive train is more proportionally loaded. Unlike the greater risk of axle breakage using larger tires the new gearing will better protect them through reduced torque. It may be necessary to start more often in first and shift more frequently on hills, but your going 20% faster in every gear. You will now be able to keep up with moderate highway traffic and, in so doing, realize a significant increase in fuel mileage. "
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