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argo
09-18-2010, 10:05
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!)

DmaxMaverick
09-18-2010, 10:54
No way on the TH350. The 700 is better in many ways, including overall strength. If you are overhauling it anyway, it isn't much more money to build it up to near TH400 ability.

However, if you want a manual, the SM465 is very good behind the 6.2, and they are fairly common. You should be able to find one already mated to a NP-208 or 205, ready to bolt up behind the 6.2. Make sure your front axle and the TC have the shaft on the same side.

Incidentally, I have a 4L60E/NV241 right here, ready to go. Tranny is like new, with only 900 miles on a complete overhaul (new case and most of the internals). It will bolt up to the 6.2, and all you'll need additional is the electronic controller and a Diesel torque converter.

argo
09-18-2010, 11:04
Since I am looking for your opinions, I will only watch this thread unless you have a specific question, because I do not want to influence the results one way or the other.

Since you already replied before I posted this, thank you for your input DmaxMaverick!