My 1978 Ford F100 has a 4 speed manual transmission, but my grandpa always told me that the first gear is for when the truck has load or is going through earrings. At first gear the truck sounds exactly like is in reverse.
Someone can explain me how is possible, the name or code for this kind of transmission, does it have any advantage over conventional transmissions and is there a replacement?

 

Is your 1st a really slow gear?

 

Yup, the max speed in that gear is about 10-13 mph

 

At a lot of the construction yards we used to call that the coffee gear. We always joked over how you could start the truck, put it in 1st, go inside to get your coffee and by the time you came out the truck would be up to the door and all warmed up.

 

Ok your transmission has a low first and it and reverse whine compared to the other gears. That is because those gears are straight cut. A straight cut gear is cheaper and stronger. Plus there are no synchros on those gears so they grind easily too. Your other gears are helical. Just Google that term and you should get an illustration of a helical cut gear.

Names: granny gear, compound low, farmer 4. Models include T98, T18, NP435 and several others. These are considered conventional transmission. Replacement would be automatics or later model 5 and 6 speed truck transmission. Unless you want a car transmission.

 

Thank you so much, now I can learn more about the transmission and how to rebuild it