Subject: planetarys
From: rotaryeng
Date: 8/29/2014, 8:51 AM
To: AA-1-Me


Hi Paul, I have been looking through Ford auto trans spec's in regards to the Ford/Jatco  parts JPG on your site, but cannot find those specs. It shows 3.17 ratio. What Ford model is that from?

Thanks Steve Carlisle

Ford has changed the tranny number over the years.
Call http://www.makcotransmissionparts.com/  sales and ask for the 6 pinion rear
planet set from an A4OD. He will know what you are after.

Paul Lamar


Okay, I am even more confused. If I new for sure what tranny has that ratio, I can buy a used trans locally. You tell me the pinion set comes from a A4OD. You can buy many 4,5,or 6 pinion sets for many models as upgrades. What confuses me now is you send a parts diagram for a E4OD. I have a trans re-builder locally and say the 2 a quite different. I have looked at the specs for the A4OD, and the offer standard ratio and Wide ratio, but no planetary with the 3.17. Sorry for the confusion, it seems not as simple as I had hoped.

Anyways, thanks for effort,  Steve Carlisle

You are talking to the wrong person Steve.
Transmission re-builders know very little about planetary theory.
All they know about is how to take them apart and put them back
together. The E40D is a descendant of the C5 that came out in the
early 50's. Most if not all the parts are interchangeable. The early
planetary had 3 pinions, then 4 pinions and the latest incarnation
6 pinions. The hot rodders had six pinions long before Ford did it.

In the mean time Ford changed the transmission designation
number several times. One of them was the E4D.  The E4OD has a third planetary
for over drive. That is the "O" is in the designation. We don't use that
planet set. That smaller planet set  is located at the front of the transmission.

If you talk to the parts guy he will know what
you are after.  The Jatco is a scaled down C6 and the parts look the same
but are smaller for the Japanese market.

The gear ratio depends on what part gets the input torque, what part puts out
the torque and what part is held stationary. Early Tracy's were 2.17:1. Later versions
were 2.85:1. For a rotary 3.17:1  gives the most power. It is also a beefier planet
set. Ross made all three. It is the last planet set in the box.


Paul Lamar

Paul, Again, thanks for the help,

Steve Carlisle

Do you plan on building gear box?

Are you in the US? Milo is just south of Seattle.

I think. He travels back and forth to Texas sometimes :)

Brian Trubee is at Paine Field. http://www.painefield.com/

Paul Lamar

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