I have a `75 F-250 with a 4-speed, I dont know exactly what it is but it has a granny first gear and I would like to have a five speed or maybe a real 4 speed. Its bolted to a 390, and its 4x4 and has the divorced T-case. What trannys could I get to bolt up? I mainly would like an overdrive, not really different gears.

Dave

http://www.davesmonsterpit.com

 

What do you mean by "a real 4 speed"? First gear is always called granny gear and most people start in second and only use it when loaded. On a Chevy they mark first gear as "L" for low, and they mark second gear as first...just to confuse everybody. Surely there's many after market trannys that could be found.

 

I think what he is referring to is a first gear that you can normally use when street driving (say about 3.8:1). I'm used to hearing "granny gear" to refer to extremely low first gear found (for example) in the NP435 which is about 6.6:1. Probably so-called since your grandmother could start off in that gear without stalling no matter what she did with the clutch.
Second gear is about 3.8:1 which is what "real" (i.e. non-granny-low transmissions) have for a first gear. Unless you are doing heavy towing or off-roading, you hardly ever use the granny low. 3000 rpm = 9 mph in my truck.

 

Your correct, I think I have a NP435 but im not sure. I want a manual without a granny gear, that will fit my 390. I do do some offroading and that first gear isnt even worth having because you have to stop to get it in, or be real good at double clutching plus it takes a half a mile to move the shifter. A five speed would be best, but I dont know if there are any for my aplication.
Dave

http://www.davesmonsterpit.com

 

 

Trail Rider is good at engineering that kind of question, maybe he will be along in a bit. Getting one to bolt to your bell and have the proper shaft length will put you in business.

John
jowilker

66 F100s
In the still cool hours of the night, you can hear chevys rusting away.