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67ChevyRedneck · 02-17-2017, 11:16 AM

It's common to have to leave a 700R in 3rd when your driving under 45 mph. Under light throttle they'll shift in OD around 40mph and these trucks are just heavy old aerodynamic bricks. I had an 86 Z28 that had a 305/700R (LOL, right? - it was S L O W!) and it did the same thing, wanted to shift into OD at 40, which was just too early. In my C10 I have a lokar floor shift so it's easy for me to bump it back and forth.

My 700R has been in my truck for +/-11 years and probably 50-60K miles. Still shifts like it did when I installed it. Fuel mileage didn't really change around town, still get 11-12mpg. Back road cruising and highway driving gets 15-16mpg. I did it more for the rpm noise drop than the mileage as I put 3-5K miles per year on the truck.

02-17-2017, 11:16 AM	#12
67ChevyRedneck Hittin E-Z Street on Mud Tires Join Date: Nov 2004 Location: Greenville, SC Posts: 23,090	Re: 4 spd auto with lock up converter It's common to have to leave a 700R in 3rd when your driving under 45 mph. Under light throttle they'll shift in OD around 40mph and these trucks are just heavy old aerodynamic bricks. I had an 86 Z28 that had a 305/700R (LOL, right? - it was S L O W!) and it did the same thing, wanted to shift into OD at 40, which was just too early. In my C10 I have a lokar floor shift so it's easy for me to bump it back and forth. My 700R has been in my truck for +/-11 years and probably 50-60K miles. Still shifts like it did when I installed it. Fuel mileage didn't really change around town, still get 11-12mpg. Back road cruising and highway driving gets 15-16mpg. I did it more for the rpm noise drop than the mileage as I put 3-5K miles per year on the truck. __________________ Jesse James 1967 C10 SWB Stepside: 350/700R4/3.73 1965 Ford Mustang: 289/T5-5spd/3.25 Trac-Loc 1968 Pontiac Firebird: Project Fire Chicken! 2015 Silverado Double Cab 5.3L Z71 2001 Jeep Wrangler Sport 4.0L 5spd 2020 Chevrolet Equinox Premium 2.0L Turbo 2011 Mustang V6 ~ Wife's ride American Born, Country by the Grace of God 1967 CST Shop Truck Rebuild! My 1967 C-10 Build Thread My Vintage Air A/C Install Project "On a Dime" Trying my hand at Home Renovation! 1965 Mustang Modifications!