Ford 3 spd OD question

Anybody know the overdrive ratio in the ford standard 3 spds with the electric soleniod overdrive? I think they were used 1952-56? in Ford cars.
Thanks
Brad

 

If it is the Borg Warner R-10 unit...When the overdrive is engaged, engine to rear axle ratio is reduced around 30%. When engaged, overdrive works in every gear...you'll have to do the math using the transmissions gear ratios.
Mike

 

Yes, it was a 30 percent overdrive. If you have 4.11 gears, the final ratio in o/d is 2.87.

 

I am only concerned with third gear. So if I have a 4.10 gear rear and have a 30% overdrive would the math be: 4.1 x .7 = 2.87 which would in effect "change" my 4.10 gears to 2.87 in 3rd with overdrive?

Brad


EDIT- I posted this before I saw heathen's post. I guess my math is correct.

 

I thought it was 74% or 76% (.74 to 1 ) for some reason.
Mine is a 51 though.
TP

 

That would be correct (70% is a 30% reduction from 100%!)...I have a 51 also.

 

I need to know exactly. so is it 30%, 26%, or 24%?
Brad

 

I'll check my manual tonight but i know its either .74 or .76 - TP