I am considering a different transmission for my 1975 F250 Crew Cab, two wheel drive with a 302 v8 and a FMX automatic transmission. For better gas mileage, If I change transmissions I would like to get something with overdrive. My current FMX has issues and either needs rebuilt or replaced. I have a goose neck hitch in the bed and occasionally pull a 25' goose neck trailer carrying approximately 15,000 pounds but the majority of driving is hauling loads in the bed on paved roads with occasional off road hauling as well.
I would like to hear from the knowledgeable people on this forum as to what transmission they would recommend and why. I am not wanting to spend any more money than necessary so some highly modified custom transmission is not an option.

Thanks

 

4R70W. Four-speed automatic overdrive. Strength. It'll need a standalone controller.

15,000 lbs with a 302? That rig must be a dog that can't even get out of its own way.

 

A 460 and a C-6 would be an easy locate and swap in, a 351M and a c-6 would be too. A 460 with a newer ZF 5 might be the cats meow?

 

The only overdrive transmission that will bolt to your 302 and still be able to handle the weight that you are intending to pull would be the E4OD. You will need an aftermarket controller to run the unit though, I think Baumann makes a nice one.

I also question a 302 and 15K lbs, may want to step up to at least a 351 if not a 460 with that kind of weight IMO!!! Not saying it won't work, but I hope you have some time on your hands to get where you need to go!!!

Mike

 

I have a feeling that overdrive, a 302, and 15k would be a horrible combination. I'd wager that you would spend most of your time hunting between 3rd and overdrive 4th.

My Dad's 93 had a 302 e40d combo that pulls down some impressive millage. However it kinda sucks in the hills with a load on it.

 

You think the transmission would actually get to 3rd gear with 15K in tow!!!

Mike

 

Sure... while going downhill just a few seconds before the whole setup jack knifes and wads itself up against the guardrail.

 

Probably on the flats. Other then that I doubt it.

 

I would think that you would be better off switching to a manual transmission than staying with an automatic. But my opinion is alittle biased because I would take an 8 speed manual transmission if anyone would offer it haha.

 

I wouldn't want to be following you with that load.. Even a stout 302 would be screaming its guts out with that load. Im really surprised that the FMX has not given out by now.


For towing that load more than just a few miles on occasion, I think its time to look for something with a few more cubes. 351w/ZF5, 400/C6/NP435/ZF5, 460/C6/ZF5/NP435 exc..