The Ford Barn - View Single Post - Columbia Overdrive Question / Information

Ford46 · 07-22-2018, 07:07 PM

A Columbia rear axle provides approximately a 27% overdrive, so to test if you set the hand throttle at 20mph, with the vehicle rear raised on jack stands, and in high gear on the transmission if you shift the Columbia into Overdrive from Standard (if all is working properly, axle and speedometer gear changer) the speedometer will show a speed of 27mph under those conditions (the rpm's are set and constant). Under actual driving conditions it will require less rpm to maintain the previous speed in Standard.

For a 37-41 Columbia the control selector was pulled out to activate Overdrive, pushed in to activate Standard.

All Columbia axles should be shifted by releasing pressure from accelerator pedal, depressing clutch, selecting Overdrive or Standard, releasing clutch after hearing click and depressing accelerator pedal. In the 46-48 models with the electric/vacuum you depress switch and hold, lift off accelerator and depress clutch (hear two clicks, solenoid and axle) release clutch and press accelerator, to shift back to Standard on 46-48 you just lift off accelerator and depress clutch. Shifts to either Overdrive or Standard ratio should always be made with the car in motion. If a shift is attempted and the car is NOT in motion, the shifting clutch in the axle may not engage, resulting in a ratcheting noise when the engine clutch id engaged. To engage the axle, shift the transmission into reverse gear and partially re-engage engine clutch.

To check the gear oil in a Columbia rear axle use the oil level hole on the Columbia axle housing (DO NOT USE FORD oil level hole!!!) Will now hold 4-1/2 pints of lubricant...today's 85/140 multi-grade oil is recommended, for a purist S.A.E. 140 in summer and S.A.E. 90 for winter. Each fall and spring, or every 5,000 miles, whichever comes first drain and refill to new oil level hole in Overdrive axle.
Every 10,000 miles remove the vacuum cylinder from Overdrive axle and lubricate leather cups, also lubricate walls of cylinder lightly with 3-in-1 oil or its equivalent (Marvel Mystery Oil).
This information is all in the Owners Manual & Primer and installation instruction sheet. LouB.

07-22-2018, 07:07 PM	#20
Ford46 Senior Member Join Date: May 2010 Location: Southeastern, MA Posts: 434	Re: Columbia Overdrive Question / Information A Columbia rear axle provides approximately a 27% overdrive, so to test if you set the hand throttle at 20mph, with the vehicle rear raised on jack stands, and in high gear on the transmission if you shift the Columbia into Overdrive from Standard (if all is working properly, axle and speedometer gear changer) the speedometer will show a speed of 27mph under those conditions (the rpm's are set and constant). Under actual driving conditions it will require less rpm to maintain the previous speed in Standard. For a 37-41 Columbia the control selector was pulled out to activate Overdrive, pushed in to activate Standard. All Columbia axles should be shifted by releasing pressure from accelerator pedal, depressing clutch, selecting Overdrive or Standard, releasing clutch after hearing click and depressing accelerator pedal. In the 46-48 models with the electric/vacuum you depress switch and hold, lift off accelerator and depress clutch (hear two clicks, solenoid and axle) release clutch and press accelerator, to shift back to Standard on 46-48 you just lift off accelerator and depress clutch. Shifts to either Overdrive or Standard ratio should always be made with the car in motion. If a shift is attempted and the car is NOT in motion, the shifting clutch in the axle may not engage, resulting in a ratcheting noise when the engine clutch id engaged. To engage the axle, shift the transmission into reverse gear and partially re-engage engine clutch. To check the gear oil in a Columbia rear axle use the oil level hole on the Columbia axle housing (DO NOT USE FORD oil level hole!!!) Will now hold 4-1/2 pints of lubricant...today's 85/140 multi-grade oil is recommended, for a purist S.A.E. 140 in summer and S.A.E. 90 for winter. Each fall and spring, or every 5,000 miles, whichever comes first drain and refill to new oil level hole in Overdrive axle. Every 10,000 miles remove the vacuum cylinder from Overdrive axle and lubricate leather cups, also lubricate walls of cylinder lightly with 3-in-1 oil or its equivalent (Marvel Mystery Oil). This information is all in the Owners Manual & Primer and installation instruction sheet. LouB.