Topic: Non-Synchromesh transmission

jyakel    -- 08-11-2019 @ 9:41 AM
I have a very stock 1949 F-3 Ford pickup with the 8BA flathead Ford V8 engine and a 4 speed non-Synchromesh transmission on the floor. It also has the very high gear ratio in the rear ending making the top speed about 45 mph.
My question is one of general understanding; why does one have to double clutch a non-Synchromesh transmission when shifting gears? What does double clutching do?

carcrazy    -- 08-11-2019 @ 2:46 PM
  Double clutching allows you to match the speed of the input gears with the speed of the output gears in the transmission. This task is handled by the synchronizers in a synchromesh transmission.

jyakel    -- 08-12-2019 @ 3:53 AM
Okay, thank you for your good explanation. Sometimes I can shift gears perfectly-like butter as they say. Other times (and I don't think I am doing anything differently) it is a challenge to 'find' that next gear.
Thanks Carcrazy,

alanwoodieman    -- 08-12-2019 @ 12:35 PM
  I tell people who are new to the double clutching to quit thinking about and just do it. you will get to a point where it is natural thing

cliftford    -- 08-12-2019 @ 12:44 PM
  Install a tach. It will help you find that "sweet spot" that is, the right engine speed for shifting each gear.

37RAGTOPMAN    -- 08-14-2019 @ 10:55 AM
to my memory serve me right, I did own a 51 with 3 on the tree, and shifting 2nd to 3rd was no problem
first and reverse are not synchro, 1st to second, 2nd to third and third TO 4TH should be synchromesh,
you might have bad synchros.
the only transmission that I know of was the MODEL A and MODEL 1932 18 -B
that you needed to double clutch,
I would drain the trans and run a magnet though the oil to see what is picks up
You could also remove the floor pan and trans top cover and look inside to see if it has syncros
maybe a oil change would help
hope this helps 37Ragtopman

CharlieStephens    -- 08-14-2019 @ 11:17 AM

The 1932 B and 18 transmissions were synchro. The large truck 4 speeds for the early V8 years also did not have synchros.

Charlie Stephens

This message was edited by CharlieStephens on 8-14-19 @ 11:20 AM

37RAGTOPMAN    -- 08-15-2019 @ 7:55 AM
thanks for the info. I never drove one of these trucks,
when did they change to a synchromesh
not really what I expected,
I guess ,, will have to learn to double clutch the non synchco transmission,

my 2 cents 37Ragtopman

cliftford    -- 08-15-2019 @ 11:40 AM
  If I'm not mistaken, the change was in 1953.

f1ford48    -- 11-06-2019 @ 2:59 PM
  thats known as a ''crash box'' it is a Warner T9 spur gear transmission. upshifting works best on mine if i do it super fast. downshifting fourth to third you blip the throttle. forget down shifting to any gear lower than third unless you are a pro...... old truckers are the best in describing how it is done.

This message was edited by f1ford48 on 11-6-19 @ 3:01 PM

Barney    -- 11-06-2019 @ 5:26 PM
  Hi John,
I agree with 'Carcrazy's' basic, to-the-point explanation - matching input (engine speed) speed to output speed (driveshaft speed). You mentioned you usually have no problem shifting, but occasionally you have trouble. My guess is you have trouble when on a hill. When traveling uphill, you're probably more hurried to shift; when traveling downhill you're probably less hurried to shift. But it's counter-intuitive. When shifting going uphill, you need to shift at a slower rate. The truck (driveshaft) will slow down faster, thus you need to wait a bit longer for the engine speed to slow down more so to match the input/output speeds. Conversely, when shifting going downhill, the truck (driveshaft) may slow down very little and may even accelerate, so you'll need to shift quickly before the engine speed (input) slows down too much. Have fun practicing, Barney

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