1962 manual. 3 speed vs 4 speed: pros/cons

[Ancientx]

Idk much about these. I just bought a replacement motor for my 62 1/2ton. I got the 3speed for free with it. My original is the 4 speed w/Granny low.

My question is, is that extra low gear the only difference?
If not, what is?

[705jmguy]

hi and good morning,

not much difference at all from my knowledge, the low in the 4speed is not of much use except for wanting to go slow with more torque, kind of a creeper gear, for normal driving one never uses the low gear, you start off in second. The high gear is 1 to 1 ratio same as a three speed tranny. Hope this helps

[bozzhogg]

Yeah that low range 1'st gear is only good if you plan on hauling a lot of rock or something. If you do not plan on using your truck for work I would think the 3-speed would be a better pick??? Ross.Hodges '66 GMC with a '12 foot flat bed.

[ilvracn]

GRANNY LOW IS GREAT FOR PARADES

[Ancientx]

Yeah, i knew about the uses of granny low. Didn't think of it's use in a parade tho'. GOOD CALL!!!

I guess I'll check the VIN and see which is the original to the truck and sell the other.... Though i like the idea of keeping the 4 speed for parades.

[Onuma]

By the way ilvracn, nice truck! That's close to the color I'd like to eventually paint my '66.

[Ancientx]

Gentlemen, i would like to propose an idea:

I am an idiot.

I failed to notice one simple, yet glaringly large detail between the two transmissions i now have.

The one in the truck is a top shifter.
The one on the motor to go in the truck shifts on the side.

Hence: idiot.

It leads me to believe it came from a 3 on the tree. Oddly though, there are two separate ( it looks like) shifters on the drivers side. The lower one will only move(3 clicks total) after the top shifter has been shifted back one click. (Totaling 3 also.)

I can't post pics here from my phone.
Where should i look for ID numbers?
I'll be posting it for sale soon as i plan to keep the 4speed.
One other note which might help: the motor #'s are: 305A67199

Thanks again for all the help. I'm a good wrench, not a great mechanic, and very ignorant of the details about this truck.

[jagarra]

Side shifters have 3 positions on each shifting arm. 1st neutral reverse on one arm. 2nd neutral 3rd on the other.

When you shift from 1st to 2nd, 1st goes to neutral, 2nd then can move to engage the gear. Column shifters have 2 arms from the column linkage, they have to move the in proper sequence to engage the gears.

[Ancientx]

Ah. Good to know. Where on the trans can i find the ID#'s?
What type of trans is it off hand anyway? Were there different trans set up with that shift?

[jagarra]

The 3 speed is the SM318 model. The 4 speed is the SM420 model. the only other transmission was the hyra-matic .