I am beginning to plan for a major overhaul to "The Argo", my trusty 1996 F-150. I am interested in making it a 4x4 (these trucks are easy to convert), with a 6.2L diesel. My question is about my transmission choices. I do not use this truck anymore as a primary vehicle. It served in that capacity for a very long time, and I enjoy driving it, but the mileage it gets makes it too expensive to operate regularly. The purpose of swapping in a diesel engine is to gain efficiency and the ability to run on homemade fuel (eventually). I want to put a 6.2L diesel in it, and I want to make it as efficient as I can without compromising it's abilities.
The truck is currently powered by the factory 300ci straight six, and has 3.73 gears, and a cast iron NP-435 4 speed manual transmission. The 4 speed can be converted with a Novak adapter and a new output shaft to run a transfer case, and it can be adapted to a GM clutch housing, so running the 4 speed with the 6.2L is a possibility. If this plan fails, however, I intend to go with a GM automatic transmission.
The truck will be fitted with 31 inch tires, and I intend to keep the 3.73 gears, because I tow and haul significant loads frequently with this truck. If I need to go automatic, I do not want to use a TH-400. While it is bullet proof
, it is a power hog, and I am concerned that it will cost me mileage and make the 6.2L feel more sluggish than the six it will replace (even though their dyno sheets are virtually a carbon copy of each other).
What I don't know however, it whether the TH-350C is stronger than the TH-700R4. If it is, I want to use it, because this truck doesn't see much highway driving unless I am towing something or hauling something heavy, in which case I don't use overdrive anyway. If they are equal strength, then I'll go with the 700 because even if I won't use the overdrive all the time, I see no reason not to have it if it doesn't cost me strength.
I want to stay with a manual, but if adapting it will cost too much, I will go automatic. So what is your choice? If extended highway speeds are not a concern, would you go 700R4, or 350C? (Note, not just a 350, because I want a lockup converter!)
1993 Suburban 2wd 6.2L Diesel Conversion "Andromeda":
3.73:1 gears, THM 700-R4 transmission, and
J-code 6.2L diesel from a 1984 C2500 Suburban
1996 Ford F-150 4x4 300ci Inline 6 "The Argo"
327,000 miles and climbing
1992 Caprice Wagon 5.0L TBI "Enterprise-D"
Ah ha ha ha! I swear! Tractors is so dumb!
The Argo? That ridiculous pile of scrap metal!