Here is is an email that was sent to me to forward to you all from a friend of mine that talked me out of building a C-6 based 3.17 ratio gearbox and talked me into using the 3.21 Dodge gears.

  He is not on this list but you may have heard of him as he is on the rotary roster as he is building a Coot with a rotary and he is using one of my 2.95 belt drives and he should be flying it this summer.

  He thinks I am nuts going away from the belt drive that I have put 900 trouble free hrs on and says he will stick with the belt even though works on transmissions for a living.

 

  Ken Welter

Date: Wed, 04 Jan 2006 06:47:42 -0800 (PST)
From: Arnold <vwsandndirt@yahoo.com>
Subject: Re: Fwd Re: [FlyRotary]Soapbox Warning!   PSRU Ratios
X-Originating-IP: [66.218.79.59]
To: Ken Welter <rotary.coot@verizon.net>

One thing I can tell you is that in the last 15 plus years that I have dealt with planetaries, I still see Ford sun gears coming apart in 80% of units I take apart and I have yet to find a bad Dodge sun gear with the exception on total planet meltdown due to a plugged trans cooler.  I am not an engineer, just an observer and a very qualified transmission expert.

 

Another thing I can tell you is that it was not the amount of pinion gears that were put into the Ford planets that made it better, it was the change from aluminum to steel to keep the splines from stripping out.  Also, the Ford planets are only being used (loaded) during up shifts and the Dodge planet set in question is being used during the long period of time the truck is towing the trailer down the highway in overdrive.

 

Good luck with your ratio debate and I hope this info is of help.

 

Arnold Norton    ASE certified

American Transmissions