2 overdrives

[Brian]

Is anyone on here running two overdrives in an early Ford? Call me mad if you will, but I currently have a fixation on overdrives. I currently run a Columbia in my 35 sedan...when I first fitted it, it was running a 3.54 ratio, which gave around 2.56:1 in overdrive. Car was a pig off the line, but I loved the gearing in overdrive, at 30 MPH it was idling, didn't need my foot on the throttle. After an accident [not my fault] which even bent the diff housing, I rebuilt the Columbia with 4.11:1 ring and pinion, kindly supplied by JM35 on here. That gives 2.97:1 in o/d.

Because my car is lowered, there is a tendency for diff oil to migrate forward along the torque tube. So, recently I adapted in a 39 Lincoln Zephyr banjo; 4.44:1 ratio, these things are hypoid, which now places my torque tube at a better angle...incidently, they also have a seal at the pinion which will keep all the rear end oil in the rear end. I haven't driven it yet; still awaiting delivery of the GL4 hypoid oil I ordered two weeks ago! However this will give me 3.21:1 when in overdrive. [I am running [repop] LZ gears in the trans]

Locally here in New Zealand, there is a fellow advertising for sale a torque tube mounted Laycock overdrive that he had previously run in, amongst other things, a 1939 LZ. This is similar to a Mitchell, which some of you guys would be familiar with.

Anyway...I start thinking about buying it and fitting it into my car. My car, equipped with the 4.44 Columbia rear end, is 3.21 in o/d, coupled with another [Laycock] overdrive would see a potential total overdrive of around 2.1:1! Remember I loved my car at 30 MPH when it was running 2.56:1. What you guys reckon? Too much? Probably, but I'd appreciate any and all feedback, particularly from someone who's been there/done that.

One real downside I can foresee is the additional unsprung weight! The Columbia is heavy, struth, that Lincoln banjo is heavy, and a Laycock overdrive isn't light either by any means.

Ok, go for it guys, I'm fully prepared for all the negative comments. Thanks

[BLACKNRED]

I have adapted a Tremec TR5050 6 speed gearbox to a 33' B Engine, took a bit of effort, I have not driven the car yet but have plumbed the hydraulic clutch and it disengages the the clutch plate, so with crossed fingers it should all work OK, at this stage test drive will be end of June

[38 coupe]

Brian, it has been done before, and first done by Ford Motor Co. In 1941 you could order a Lincoln Zephyr with either a Borg-Warner overdrive (30% over), a Columbia (28% over), or both! The car that won the 1941 Gilmore Economy Run to the Hoover Dam was a Lincoln equipped with both overdrives.

In your case the easy shifting of the Laycock unit probably adds to the fun, with the Columbia being used more as a range box, going into overdrive only at speed. I don't like to lug engines that much, but 12 forward ratios could be entertaining.

[Terry,OH]

There is a hot rod shop in Texas that sells an adapter that fits in front of the differential banjo and inside the torque tube. it has a modern seal to retain oil in the banjo. The seal rides on the O.D. of the coupling for the drive shaft.

[glennpm]

I installed one a couple of years ago at the same time I replaced my Columbia clutches.






Glenn

[38 coupe]

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I'm curious about that seal kit, how do you get the splines to seal up so gear oil does not weep around the seal through the drive shaft coupling?

[glennpm]

Originally Posted by 38 coupe

I'm curious about that seal kit, how do you get the splines to seal up so gear oil does not weep around the seal through the drive shaft coupling?

Hi Fred,


The coupler to spline is sealed. I used RTV. I also added a vent to the left side axle housing per the instructions. Good picture is from 19Fordy

[38 coupe]

Glenn, thank you for the picture and instructions.


Brian, apologies for taking your thread and wandering off on a different topic. Back to our regularly scheduled discussion.