Help! How do I use a Columbia rear end in my 1940??!!

[billy’s40]

I have heard conflicting arguments about how to use the Columbia overdrive system. Some people say it has to be engaged when you’re going 10 to 15 miles an hour, and others say you activate it when you are at freeway speeds. What is the correct way to use it? Can it be left on all the time? The lever is mounted under the dash and can either be at high or low setting. Thanks in advance for your help.

Billy

[Kube]

Billy,
Push the clutch in, let off on the gas and pull the knob out to engage the Columbia. Let the clutch back out and drive.
To get back into the normal gears, same procedure except push the knob in.
I tend to shift at no higher speeds than around 40. I KNOW my Columbia is built properly. Still, I'd never grown comfortable shifting at higher speeds.

You most certainly may leave the overdrive engaged. You may find pulling away from a dead stop is a bit labored. This of course depends on the gear ratio of your differential and how strong your engine is.

Under no circumstance should you abuse the Columbia. In other words, no "power shifting". Let the changer do it's job.

You'll get the hang of it soon enough.

[solidaxle]

You could shift it at 10-15 miles an hour but it's not necessary and there's no advantage. It all depends if there's an uphill in front of you. I go through the regular transmission gears then shift to high. Just don't take off in high always make sure it's in low before you come to a stop.

[Ken/Alabama]

What Kube said. Also never attempt to shift it without the clutch pedal pressed and always rolling. I’ve heard some folks say they first pull the knob out the push the clutch to make the shift. I think that could be a recipe for disaster.

[Bob C]

Maybe get the Owners Manual. https://www.amazon.com/COLUMBIA-OVER.../dp/B00HIFZAUK

[Cool Kat with Hot Car]

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Never shift without using the clutch as you would when shifting the transmission. Do not leave the rear in high, come to a stop and, start out in high. The strain of overcoming the inertia from a stop should be taken by the ring and pinion, not the much more fragile Columbia planetary gears. Always keep the lube topped off in the rear axle at the fill fitting on the Columbia housing. The cavity for lube is shared by both cases, if the volume falls to the level of the Ford plug you will kill your Columbia.

[Terry,OH]

Good idea is to check the lube level before using on the highway. Fill the differential all the way to the bottom of Columbia fill plug. Jack the rear wheels off the ground and using jack stands and blocks on the front wheels. Start the engine and place the Columbia in high gear Let it run for 5 Min. recheck Diff fluid and refill again to the bottom of the Columbia plug. Use 140W, I use N.A.P.A. SL24238.

[glennpm]

HOW TO SHIFT the Columbia OVERDRIVE AXLE

The shift to either Overdrive or Standard ratio is
SEMI-AUTOMATIC. It is electrically controlled
and can be made at the will of the driver, ac any car
speed.

TO SHIFT TO OVERDRIVE

Pull knob out Depress OVERDRIVE selector, and holding it
in this position, release pressure on accelerator and
fully depress clutch pedal. Allow clutch to re-engage
gradually and smoothly, then release selector.

TO SHIFT TO STANDARD RATIO

Push knob in The shift is AUTOMATICALLY selected, and completed
by merely depressing clutch pedal to floor, and allowing clutch to re-engage gradually and smoothly.

NOTE: Before coming to a complete stop, when in overdrive ratio, push knob in, depress clutch pedal to floor to ensure a complete engagement of the axle into
the standard axle ratio.

The shift to either OVERDRIVE or STANDARD
ratio should always be made while car is in motion.
If a shift is attempted when car is not in motion, the
shifting clutch in the axle may not engage, resulting
in a ratcheting noise when the engine clutch is
engaged. To engage the axle, shift transmission
into reverse gear and partially re-engage engine
clutch.

[glennpm]

I shift mine at speeds lower than 40 MPH.

For other controls, this part of a V8 club meet,"Shifting Into Overdrive – January Garage Tour" are helpful:

"Cliff then described how the Columbia is operated by the driver. The first thing a driver has to remember is that the car must be moving when the Columbia is shifted into overdrive and also when it is shifted out of overdrive. To shift into overdrive, the dash control (lever on ‘35/’36, knob on ’37-’41, and spring loaded electric switch on ’46-’48) is activated (turn lever to “H”, pull knob, or hold down switch). The driver then takes his foot off the accelerator pedal (to create maximum vacuum) and fully depresses the clutch which completes the shift. On ’46-’48, the driver also then releases the spring loaded dash switch. To shift out of overdrive, the driver returns the dash control to the standard position (on ’46-’48 the control switch automatically returns to standard position), takes his foot off the accelerator pedal, and fully depresses the clutch which completes the shift."

[petehoovie]

Originally Posted by Cool Kat with Hot Car

Never shift without using the clutch as you would when shifting the transmission. Do not leave the rear in high, come to a stop and, start out in high. The strain of overcoming the inertia from a stop should be taken by the ring and pinion, not the much more fragile Columbia planetary gears. Always keep the lube topped off in the rear axle at the fill fitting on the Columbia housing. The cavity for lube is shared by both cases, if the volume falls to the level of the Ford plug you will kill your Columbia.

[GSCOV]

I have had several hot rods that had Columbia rear ends installed for the purpose of having a higher ratio. None had controls or vacuum lines run. They had to start out in high as it was fixed to be that way.