Does anybody have a parts list with numbers for the gearbox?

Kevin Alderman



Tracy's gear box? I can give you part numbers on the planetaries.
His prop shaft and flange was based on a modified  GM truck rear axle and bearing.

The rest of the parts are custom made.

The rear planet is  Slauson Transmission Parts E4D 40. Front planet is E4D 30 Sun Gear E4D 28
Rear ring gear E4D 74. Front Ring gear E4D 61.

Paul Lamar

Paul, if memory serves, the only thing that holds the axle bearing to the axle was a light press fit on the axle, and then a press fit lock ring. Is that right, NAW, could not be just that, right?

Steve Carlisle

It is not a light press fit. It was done with a 20 ton press.
That takes all of the prop thrust. That also holds the wheel in and the axle
on in the truck.


Paul Lamar

Paul, on this type of axle, I believe the bearing is held in the diff housing by a bearing retainer plate, usually attached
with 4 bolts. The axle is held into the side gear with a heavy clip , which fits into a groove at the start of the axle. On the redrive in question, it seems the output propeller shaft, with propellor is only held in with the proper interference fit.
It seems to work , so far !

Steve Carlisle

No. Tracy holds it in with a retainer plate that is screwed to the housings with a bunch
of 10-32 screws. These screws take all thrust loads. See the attached jpg.

BTW I finally figured out why Tracy was using that O-ring that Scott mention.
My guess is he had a bunch of cases machined for the 2.12:1  wherein the ring gear
rotated.  Those cases were bored to a large enough inner diameter for the ring gear to rotate.

Tracy finally realized that 2.12:1 was not going to cut it with a rotary. The tip speed
on the prop was limiting the RPM and the HP. We talked a lot about that on the
newsletter and I have all those old messages. He had to lock the ring gear and
take power out of the planet holder instead.


So he used the same front planet
carrier because he had them in stock and used that powdered metal bulkhead to
keep the ring gear stationary in the now  over sized case . The ring gear is a sloppy
fit on the bulkhead so he needed a way to damp that out. It probably rattled when
he ran the 2.85:1 for the first time. No problem for the operation because planetares
are self aligning. Hence the O-ring.

My fix for the bulkhead is to coat the ring gear with RTV. In theory that alone
would prevent the ring gear from rotating as the adhesive strength is 3,000
pounds per square inch, The half inch extended point set
screws are belt and suspenders and the RTV does the damping.

I suggest the rear planet instead as that will yield 3.12 to one gear reduction.
Much more power.

Paul Lamar


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