What’s the trick to a smooth transition between low and high gear?

[Reno Speedster]

The 22 is running great and I have been driving it a bit. Most times I can go from low to high with no fuss. Sometimes I get juddering. I am throttling back a bit before the shift. What am I doing wrong? Should I be feathering the shift like you do a normal car clutch? Should I be doing it briskly?

[Rich Eagle]

I throttle back all the way before shifting.
Rich

[JTT3]

A balanced & aligned tranny & engine helps too

[Kerry]

To many clutch packs (especially modern ones), drive plates, key ways, axles and diff pinions etc, are stuffed by bad driving habits. I don't blame the driver but the one who taught him. The throttle needs to be fully backed off when releasing from low to high.

[Moxie26]

Reno..... Instead of cutting back on the throttle, leave it in that position you want to speed in low gear, and instead of cutting back on throttle cut back on your spark halfway the same time you lift your foot off the clutch to get into high gear. ... Try it, you'll like it.!! ..,....... And then advance your spark to the car speed you want, also adjust throttle to speed limit signs and road conditions.......... Keep in mind that the throttle will control the speed of the vehicle, and the spark controls the speed of the engine. So when you shift from low to high , engine RPM will be cut a little more than half RPM due to direct gearing, so that's why I retard the spark halfway of the advance I have in low gear, gives a smooth shift into high gear because of the timing change on a slower running engine at that moment.

[Scott_Conger]

Technique is 1/2 of it. The other half is the type of clutch. My experience is that FORD clutches shift smooth as silk if the throttle is momentarily closed and reopened just at engagement.

My father's depot hack has (I think) a Jackrabbit clutch and I have never made better than 10% of the time having a smooth shift...the other 90% are slam/bang shifts no matter what.

If you know what type it is, you should state it and the advice you receive can be tailored to it (including warnings for non-stock clutches)

[Art M]

I try to shift between 10 and 12 mph which results in engine speed of 400 to 500 rpm. I don't like to lug the engine. Several years ago I used tried a farm store conventional 10 w 30 detergent oil which made the transmission very jumpy. I temporarily calmed it down by adding some synthetic oil, until I could change the oil. Since then I use Shell conventional oil and have no problems. I back off the throttle but not sure by how much, because the maneuver is now so automatic.

Art Mirtes

[Tadpole]

The clutch on the only T I have experience driving shifts very smooth when the engine is cold. But as everything warms up and expands it becomes harder to get a smooth shift. I most often end up with a “SHUNK” clutch spring sound whenever I shift up or drop the pedal into neutral. I have no idea what kind of clutch I have. (Don’t mean to derail this good thread nor the author’s questions, just had similar expirience to add)

[randahl]

Don't over think it and don't fight the machine.

[TXGOAT2]

I would use the throttle to control the engine speed. When shifting from low to high, the engine needs to slow down quite a bit to allow the clutch to take hold when both the drive and driven side of the clutch are revolving at or near the same speed. The quickest way to slow the engine down is to close the throttle. If the car is in fair to good condition and the controls are adjusted properly, a quick, smooth shift from low to high can be made. A quick shift conserves car momentum and if the engine and car speeds are matched just right, little or no engine momentum will be lost. A Model T can provide a quick, firm, smooth shift from low to high that is the equal of what any modern automatic transmission can provide.

[TXGOAT2]

Do not slip the clutch. Match the speed of the engine to the car speed in the gear you are shifting to. You can't get from low to high without going through "neutral". To go smoothly from low to high, the engine must slow down during the brief moment the car is in "neutral".

To go from high to low, you must speed up the engine during the moment the car is in "neutral" between high and low.

[Norman Kling]

The trick is to anticipate what is coming when you shift. As you lift your left foot on the pedal, pause for just a microsecond in neutral as you push the throttle up. Then quickly let the pedal all the way out as you increase the throttle. If you are on level, go 10-12 mph. If you are on a slight incline, you will need to rev the engine a bit more in low before shifting. And when shifting down from high to low, you leave the throttle down and just push the pedal. The trick is to get the engine running at the rpm you would be after the shift. So shifting up the engine must slow down and when shifting down the engine must speed up. Do not feather the clutch but move it quickly, not popping it fast but just lifting the foot quickly so the the amount of slipping is minimum. As you practice, you will get better at it. Especially when driving on familiar roads. Even the load on the car will make a difference. With a touring it shifts one way when I am alone and adding each passenger will make a difference. I have hills I can climb all the way in high, but have to shift to Ruckstell when I have passengers.
Norm

[speedytinc]

A stock clutch was designed for some slip. (controlled) That amount of slip can be friendly, slipping or harsh.
Your clutch , if stock, has the fingers set to tight. Adjust to add more slip. Back off the adjustment 1/2 turn each finger till you have a little slip in transition but no slip upon acceleration in high. (once you confirm a stock clutch pack.) This can be identified looking @ the inner disk tabs in the center drive hub.
See that section of the service manual.

Regarding the th400 type clutches. They will wear out fast with the same kind of slip as stock.
Drive it as you would any modern manual transmission. Ease off the clutch pedal a bit slower. Dont jump off as you would with a stock clutch pack..

[RGould1910]

John pretty much nailed it. All the technicque in the world won't overcome misalignment and especially imbalance. I once had a car that would vibrate badly between shifts. I tried changing clutches and a variety of things to fix the problem. No luck. I finally decided to have a knowledgeable T guy balance the rotating parts in the engine and transmission. The cank flywheel and drums were dynamically balanced. The rods and T gears by weight. What a difference! No vibration. The fellow told me the crank was 22 grams out of balance.

[JohnM]

Unless I'm in traffic or need to get a running start on a hill, I shift sooner rather than later. It is easier to shift smoothly at lower engine rpm and it is easier on the drive train. As was said, close the throttle when shifting, retard the spark some at slower rpms then slowly pull the throttle and spark down until your desired speed.

[Reno Speedster]

Thanks for the tips. I don’t know what clutch I have in this car. I just changed the oil to 10-30. Not sure what was in it before.

[TXGOAT2]

An engine that is in good tune that will allow a low idle speed setting makes shifting easier. It also helps with engine braking.

[Been Here Before]

Low to high.
Ease up on the throttle, decrease engine speed.
Slowly transition from low range to high.
Increase motor speed.

Putting the hobby back another 60 years (c).

[John Codman]

Practice...

[Moxie26]

Hey Reno ..... When you have a chance to sample our suggestions, let us know how you made out

[Reno Speedster]

Will do. I won’t drive it till the weekend.

[Loftfield]

Robert's advice about using the spark advance has merit. I have never tried it when shifting, but retarding the spark has wonderful good effect when the engine is lugging. I believe that retarding the spark in the slow speed lug may help forestall joining the two-piece crankshaft club. While the Model T seems to not be too concerned about spark advance and is apparently very forgiving, in driving my Model 10 Buicks the spark advance is critical to smooth engine operation. Driving today to lunch with the Model T group I will try retarding the spark during shifting rather than the long-used throttle closure. Wonder if the old dog can learn a new trick?

[TXGOAT2]

You will find that using the throttle to regulate engine speed and power will give good results.

Less spark advance is needed when running at low engine RPM with the engine loaded.

Using the spark advance lever to regulate engine timing to suit the operating conditions of the moment (engine speed and power demand) will give good results and avoid needless engine strain.

[Moxie26]

Pat and you are right ! ... So that is why it's beneficial to retard your spark halfway the moment you shift direct drive. Try it, you'll like it.

[TXGOAT2]

Adjust the spark to suit the engine's requirements as dictated by speed and load.
Low speeds in high gear under any significant loading call for a retarded spark.
There is a reason why Ford put the spark and throttle controls at the driver's fingertips.

[Been Here Before]

Additional advice to operate a Model T:

1. It is operated by ear - much similar to tuning a coil.

2. Once on the road, drive by the seat of your pants.

3. Intuition...you can never make a mistake if you drive your Model T by intuition.


After you succeed learning to drive a Model t, and have not done so already, take up motor cycling. Two pre-war bikes of choice, possibly are Indian or Harley. Controls are opposite, and you have a choice of shifter location and foot operated clutch.

As stated it takes practice, and do not be intimidated. A model T is fairly indestructible.

Putting the hobby back another 60 years (c).

[Moxie26]

Loftfield.... Enjoy your lunch and I'm sure we'll hear from you later on. Thanks.

[MKossor]

1. It is operated by ear - much similar to tuning a coil.

Not all Advice is good advice. For example......

[DanTreace]

Should I be feathering the shift like you do a normal car clutch? Should I be doing it briskly?

Just use the Ford instructions in the owner's manual. After experience you won't use the hand lever, but throw it forward and hold the low pedal 1/2 way for neutral and begin your underway. Travel about 20 feet or so, in low, perhaps up to 6-8 mph, then release low pedal to high the same time you throttle down, and then throttle back up as the shift happens for smoothest transition to high.

Made a YouTube video of my shift to high after a bit of repair for a low speed growl.



LINK to Video




https://youtu.be/AJZ8VLPtslQ




Added good info from the Ford guru Murray Fahnestock:

[Charlie B in N.J.]

I with the spark guys. Always worked fine for me.

[Reno Speedster]

Retarding the timing when I backed off on the throttle did the trick. Thanks for the advice.

[TXGOAT2]

Don't run the engine at full advance at low RPM with a load, whether you're shifting or not.
Use the conveniently located fingertip control to adjust engine timing to suit whatever the engine operating conditions of the moment happen to be.

[JohnM]

Regarding the timing when I backed off on the throttle did the trick. Thanks for the advice.

Great! Get out and drive, you'll get even better. It's not rocket science.

[Moxie26]

Hey Reno .... Did you back off halfway on the spark lever??? or the throttle ?

[TXGOAT2]

You're allowed to use both, and you ought to.

[JohnM]

It was suggested the throttle, but I'm assuming he knew to retard the spark at lower rpms.

[JohnM]

You're allowed to use both, and you ought to.

Pat, your advice is usually spot on, and sometimes redundant.

[Aussie16]

An interesting topic. My preference is to fully engage the low gear pedal,full pressure applied,apply some throttle until moving forward at a reasonable speed then back of throttle to zero,let low gear peddle out and reapply throttle once direct drive,high gear is engaged. Works for me. Never tried to retard ignition?

[Loftfield]

Have now had a chance to drive quite a few miles retarding the spark when shifting as per suggestion from Robert in New Jersey. It definitely works. I cannot say with certainty that retarding the spark instead of the throttle gives a smoother shift (if it does the difference is slight), but there is a definite sense that the car moves ahead faster. My thinking, however muddled, is that since the Model T carburetor lacks an accelerator pump, there is always a bit of lag between pulling down the throttle lever and the intended response from the engine. If the throttle is kept in place for the shift, and engine slowed by retarding the spark, when the spark is re-advanced, the throttle is already open and drawing fuel, hence a somewhat faster acceleration after the shift. Meanwhile, the only serious downside to retarding the spark for shifting is the agony of remembering to unlearn several decades of practice slowing the engine by use of throttle, plus being constantly somewhat startled by the change in engine noise as the spark retards. Since we all tend to drive by ear it, again, takes some practice to not panic at the change in engine sound.

[TXGOAT2]

You will get the best results by using the throttle and spark levers as needed, as they were intended to be used. The same is true for the clutch controls.

Timing and carburetor mixture controls affect engine performance and response. Unlike more modern vehicles, these functions are not automated on the Model T.

Manual controls are provided to allow the operator to manage the engine operating parameters to the best advantage under a wide range of operating conditions of vehicle speed, engine speed and load, altitude, engine temperature, and ambient temperature, should the operator care to do so.

Clutch slipping should be kept to the absolute minimum. It is not necessary to slip the clutch when shifting from low to high.

[Ed Fuller]

Practice...

John gave the best advice.

Drive and enjoy it!

[Moxie26]

Loftfield .... Sorry for your agony associated with habit history, but I guess we're accepting to learn a little something everyday that's a little bit different and gives better results. Thanks for your post, I'm sure you have encouraged others to try.