Merry Christmas all!

I am new to the Forum. Just bought a 1951 F-1 straight six, four speed (granny 1st) on the floor. It seems to shift ok (double clutching), but I can't down shift at all even when I disengage and engage the clutch while giving a little gas to have the engine speed match the gear speed. On the web, I have watched videos of folks doing this quite easily. But, my truck just grinds with no action no matter what I do. Is there a chance I have a clutch problem that does not allow me to down shift at all? Any advice will be greatly appreciated!

 

You don't really need a clutch to change gears once you are moving. Clutch is only necessary when you come to a stop.
To practice find a secluded stretch of road that's slightly downhill for a decent stretch. While driving around 30 MPH, in 3rd, slip your tranny into neutral without using the clutch. This is best done by easing up on the accelerator so you are neither gaining speed or loosing speed. This unloads the gear train and you can slide the gears into neutral. Now without changing engine speed slip it back into third. Try going back & forth from 3rd to neutral a few times just to get familiar with it.
If your vehicle speed and your engine speed haven't changed you should be able to move in & out of gear at will. If your vehicle should slow down while in neutral, then you will need to slow your engine speed an appropriate amount to move back into 3rd W/O grinding gears. Conversely, if your vehicle speed increases you will have to increase your engine speed to match.
The hard part is moving the shift lever through the detention and feeling just when the gears touch each other.you should be able to feel , through the shift lever, if the gears are matched in speed or not. Adjust your engine speed to suit.
Remember we are only going in & out of third gear. Practice makes perfect. Become comfortable with this before trying to downshift.
Now, trying to downshift, it's the same process only when you come out of third you will have to increase the engine speed to match the speed of the second gear. It would help if you had a tachometer so you could see the engine speed. Practice, practice, practice. Did I say practice?
I drive an '02 F350 with a six speed manual transmission and I never use the clutch once I am moving. From a stop I accelerate in second gear, up to about twenty MPH, then I apply a backwards pressure on the shift lever while backing off the throttle. When the gears are unloaded the shift lever will go Freely into neutral. All the while I am holding the throttle at the same speed then when I move the shift lever to third I lower the engine speed about 400 RPM th match the road speed for third gear.
Hope this helps. I know it's kind of wordy but it is a difficult process to describe.

Good luck & Merry Christmas.

 

He's got the crash box four speed and as far I know there's no way to downshift it without using the clutch, at least I wouldn't. It takes practice to able to downshift without going. Your clutch could also be worn.

 

Welcome! Merry Christmas to you as well. I'm sure Fix may be correct - but listen to Bob. As a practical matter, there are very few circumstances where down shifting is needed. Unless you're hauling a heavy load or going up a steep hill, your brakes are the better way to go.

On the clutch, any chatter when starting out in first?

 

As fixnair said clutch not needed. You are only dealing with a four speed.
Try a 10 or 13 speed no clutch. Simply; the input / counter shaft must match
the selected gear (rpm) that its turning. Once thats mastered then you are
a trucker.......

(how many women class 8 truckers out there that don't need a clutch ah)

 

As Bob said i would not down shift it without using the clutch & i am pretty sure that your trans is not syncronised-you may need a new clutch

 

Fix and Big Job are right. I used to drive the big rigs and my experience matches theirs. I have a 1985 F250 dually with a four speed and can drive it anywhere without using the clutch except stopping, starting, and reverse. Downshifting into the granny gear is tricky if you get out of practice. If you could ride along with someone who can do this it might help you learn faster. But the only way to really learn is to practice doing it. If your pilot bushing is bad it will affect your shifting.
Elmo

 

Well, I'm really impressed with anyone who can shift a spur gear transmission without using the clutch. I'd love to watch you do it and learn from you.

I have also shifted without using the clutch on synchro trannies. Not really all that difficult. But I sometimes still have trouble NOT grinding the 4 speed spur gear crash box while double clutching.

As far as downshifting is concerned, I can do it, but it is harder than upshifting. I'm still practicing that one. For some reason, the speed matching seems to need to be more precise than when upshifting.

 

I would venture that there have been a few of these old trucks sent to the junkyard and the drivers to their demise when a downshift was missed prior to starting down a steep grade. Just a skill you had to know when driving in mountains with a heavy load.

 

When I first started driving my F-2 just ground the gears to downshift until one day I was at a car show and met the original owner of a '51 F-6. I asked him the secret to downshifting a non-synchro tranny. Now about 90% successful. I still grind some but it's almost like magic when the tranny slides down quietly.

 

Thanks all for some great advice! Bob, I am curious to know what the "old timer's" advice was to you?

Merry Christmas to everyone!

 

I tried to convey how I downshift on my website:

Shifting a Non-sycro Four Speed

 

And that works!

I'm still unclear about the fellas upshifting without using the clutch. I will not try it, as I still grind occasionally when double clutching. Anyone who says they can do this, please clarify whether the trans was a synchro or spur gear.

 

My 85 is synchro in the top three gears. Some of the big trucks I have driven were not!
Elmo

 

And where are our manners? Welcome to the forum. And Merry Christmas.