Of gears and towing... - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Quikshft · 09-03-2019, 11:02 AM

Hey guys, my truck is currently an L31 350 with an SM465 and 3:07 axles with 33” tires. It cruises the freeway quite nicely, but I tow an 18 foot RV that weighs about 4500 pounds, at 55 mph the engine is 1700 rpm. I have been thinking about upping the axle ratio to 4:10 which would result in a 55 mph cruise of about 2300 rpm which I believe is closer to optimum.

I have considered the Ranger Torque Splitter, when engaged it reduces engine rpm by 22%. Interestingly in 3rd gear with a Ranger engaged, my engine rpm at 55 mph would be nearly identical to what a 4:10 axle gets me – 2300 rpm.

If I actually went through with this, I’d be putting a lot of miles on the transmission in 3rd gear. Does anybody see a problem running/towing with the SM465 in third gear?

09-03-2019, 11:02 AM	#1
Quikshft Registered User Join Date: Oct 2010 Location: Kingsburg, Ca. Posts: 92	Of gears and towing... Hey guys, my truck is currently an L31 350 with an SM465 and 3:07 axles with 33” tires. It cruises the freeway quite nicely, but I tow an 18 foot RV that weighs about 4500 pounds, at 55 mph the engine is 1700 rpm. I have been thinking about upping the axle ratio to 4:10 which would result in a 55 mph cruise of about 2300 rpm which I believe is closer to optimum. I have considered the Ranger Torque Splitter, when engaged it reduces engine rpm by 22%. Interestingly in 3rd gear with a Ranger engaged, my engine rpm at 55 mph would be nearly identical to what a 4:10 axle gets me – 2300 rpm. If I actually went through with this, I’d be putting a lot of miles on the transmission in 3rd gear. Does anybody see a problem running/towing with the SM465 in third gear?



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