So, got a little argument going
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Government Teat-sucker
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From: Virginia Beach
So, got a little argument going
With the son. I have a '88 F150, inline 6 with 4 speed overdrive. I say it is a five speed, he keeps insisting it is a four speed with an overdrive. I say it has 5 forward speeds, it is a 5-speed. What say you guys? Wasn't the 4 speed with overdrive simply the precursor to the 5 speed?
(It really makes no difference, I just wanted to know which is 'more' correct)
(It really makes no difference, I just wanted to know which is 'more' correct)
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From: torrington,ct
4 speed "plus" overdrive or 5 speed. either way, 5 forward gears = 5 speed, dont matter how you cut it, 6 of one or half a dozen of another is still 6. an 18 speed is called an 18 speed, not a 10 speed with a spliter on the top and bottom.
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You are correct.
You have a 5 speed overdrive transmission.
I have a 4 speed overdrive trans in the E150.
Both of these have one box and one shifter.
Calling these 4 + OD or 3 + OD is wrong.
A 3 + OD was in fact used for many years in Fords, and other mfg had their versions. A BW three speed had an electric OD unit attached to the tailshaft housing. A separate switch controlled the OD.
My brothers old Volvo had a 4 + OD, a 4 speed regular box with an electrically shifted OD on the tailshaft housing. Swich on top of the shifter.
Corvettes of certain years had a 4 speed main box with an od on the end with could be used in 2,3 & 4.
You have a 5 speed overdrive transmission.
I have a 4 speed overdrive trans in the E150.
Both of these have one box and one shifter.
Calling these 4 + OD or 3 + OD is wrong.
A 3 + OD was in fact used for many years in Fords, and other mfg had their versions. A BW three speed had an electric OD unit attached to the tailshaft housing. A separate switch controlled the OD.
My brothers old Volvo had a 4 + OD, a 4 speed regular box with an electrically shifted OD on the tailshaft housing. Swich on top of the shifter.
Corvettes of certain years had a 4 speed main box with an od on the end with could be used in 2,3 & 4.
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Originally Posted by phatpharm85
4 speed "plus" overdrive or 5 speed. either way, 5 forward gears = 5 speed, dont matter how you cut it, 6 of one or half a dozen of another is still 6. an 18 speed is called an 18 speed, not a 10 speed with a spliter on the top and bottom.
Postmaster
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From: Marion, VA
The modern definition of OD is that for each revolution of the input shaft, there is less than a complete revolution of the output shaft. The traditional definition of OD is very different. Traditional OD was a standard transmission that had a 1 to 1 input/output ratio and the OD unit was placed behind it that changed the ratio to an overdrive (less than 1 revolution for the output shaft vs the input shaft). On many six speed transmissions, the final two gears are overdrive. That's how the Tundra can have a 4:30 rear end ratio and still get "decent" MPG. The topo two speeds on my motorcycle are OD with the 6 speed.
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Hotshot
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From: iowa
the only ones you could count one less then all forward gears on and be even remotely correct was the old granny low 4spds, they technically were a 3 speed with a Low gear. you see this done in big trucks too, you can have a 10 spd or a 9spd but a 9 spd has the same shift pattern and even has 9 forward gears but you never use "first" because it's too low to be practical for anything (another version is the 8spd which you don't come back to first when you shift to the high side) so basically as a general rule if taking off from a dead stop and properly going through the gears how many do you use? in your case those trans actually do use first thus it's a 5spd
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From: The Big, Oregon
Originally Posted by osbornk
The modern definition of OD is that for each revolution of the input shaft, there is less than a complete revolution of the output shaft.
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Government Teat-sucker
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From: Virginia Beach
Well, thanks, fells. I sort of knew the answer but knew I'd get an education asking the question. The truck will easily take off in second gear, but first isn't as low as a granny gear- I have driven those before.
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From: Marion, VA
Originally Posted by Ford_Six
That would be an underdrive, or gear reduction. Overdrive is the output shaft turning more than the input shaft, most in common use today are around the .75:1 to .8:1 range, but I have run into overdrives in the .6:1 range.