Rammanx3

Getting ready to pull the trigger on a new Ram 3500 to pull our heavy 5th wheel RV that weights 20K loaded. Been pulling with a Volvo 610HDT with the Cummins N14 and had to have the smiles on my face surgically removed. But, now the wife has to do a good bit of the work so we want something more manageable.

Actual trips now will be short so I am wondering if the 3.42 axle ration will be sufficient or should I opt for the 3.73? It seems they put the LT235 tires on the 3.73s and 2.75 tires which are taller, on the 3.42. Wonder why?

What kind of fuel mileage could one expect with these ratios?

Thanks!!

nkennedy

I have the 3.73 with the 68RFE trans. It pulls our 12K LB fifth wheel well at 55 to 62 in 5th, or 68 to 75 in 6th. It will hold 6th down in lower speeds, but the EGT's get a little higher than I like. Not sure if you're going Asian trans about gear ratios. Whichever you choose try to get it where you pull around 1800 RPM's.

Rammanx3

Thanks for the comeback!

What kind of mileage are you getting and what is the difference between the two trannys?

CoastalDav

I’m pulling a 20,000 lb fiver, see signature, the 68rfe runs at 195 to 200 degrees. Even warmer under load. The Asin would be a better choice for heavy towing. It runs around 165 degrees most all the time. It shifts like a big rig Auto between 1st and second and locks up in third gear. I tow in fifth since it won’t stay in 6th. Need some 4:30’s to stay in 6th.

3:42’s will get you about 7-8 mph and you’ll be in 4th or 5th gear.

I’m doing 10 to 10.5 mpg. 9’s in 6th at 63 64 mph.

Dave