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Transmissions and Rear Ends Three on the tree or four in the floor? Shift it all here.

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  #1  
Old June 24th, 2015, 01:29 AM
Ancientx Ancientx is offline
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Default 1962 manual. 3 speed vs 4 speed: pros/cons

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?
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Old June 24th, 2015, 11:25 AM
705jmguy 705jmguy is offline
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Default Re: 1962 manual. 3 speed vs 4 speed: pros/cons

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
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Old June 24th, 2015, 08:01 PM
bozzhogg bozzhogg is offline
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Default Re: 1962 manual. 3 speed vs 4 speed: pros/cons

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.
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Old June 25th, 2015, 02:58 PM
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ilvracn ilvracn is offline
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Default Re: 1962 manual. 3 speed vs 4 speed: pros/cons

GRANNY LOW IS GREAT FOR PARADES
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Old June 25th, 2015, 09:02 PM
Ancientx Ancientx is offline
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Default Re: 1962 manual. 3 speed vs 4 speed: pros/cons

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.
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Old June 25th, 2015, 09:04 PM
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Onuma Onuma is offline
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Default Re: 1962 manual. 3 speed vs 4 speed: pros/cons

By the way ilvracn, nice truck! That's close to the color I'd like to eventually paint my '66.
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Old June 27th, 2015, 02:26 AM
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Default Re: 1962 manual. 3 speed vs 4 speed: pros/cons

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.
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Old June 28th, 2015, 03:29 AM
jagarra jagarra is offline
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Default Re: 1962 manual. 3 speed vs 4 speed: pros/cons

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.

Last edited by jagarra; June 28th, 2015 at 03:35 AM.
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Old June 28th, 2015, 08:31 PM
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Default Re: 1962 manual. 3 speed vs 4 speed: pros/cons

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?
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Old June 29th, 2015, 10:10 PM
jagarra jagarra is offline
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Default Re: 1962 manual. 3 speed vs 4 speed: pros/cons

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