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To be qualified as an "overdrive" tranny, the top gear must be less than a 1:1 ratio. While the E40D is a 4 speed automatic, it effectively is a 5 speed. Most automatics are effectively one more speed than rated because of the torque multiplication effect of the torque converter, which upon take off doubles up the torque at the expense of halving the speed, so you get an extra low take off gear. That is one reason the first gear in an automatic is usually not that low, typically 2.50:1, but the torque multiplication effect will usually double that for digging out of the hole. I think the E4OD on my motorhome actually has more than a doubling effect, but can't remember the exact amount (2.4 maybe).
the e4od is a 4 speed with 4th being overdrive it also has a lock up converter that will lock up in any and all gears
. so i guess you would call it a 4 speed trans.
sorry to disagree with tall paul but it only has four different gears not 5 but it does feel like 5 when the converter locks up.
Well, guess I could have said it differently. The E4OD is a 4 speed, but the bonus is that first gear functions like a lower gear on take off and so you sort of get a variable ratio out of first.
Whatever the gears are called, their ratios are:
First = 2.74, (this could be off, I've also heard it's 2.84)
Second = 1.55,
Third = 1.00,
Fourth (OD) = 0.71.
For comparison, my C6 auto's ratios are:
2.47, 1.43, 1.00