I'm not bashing your thread, and you asked why it isn't in use. Stop and think about what that article is suggesting. It's talking about uninterupted power flow from the engine to the wheels through two shafts. This is done 'wet clutches' 'Phasing in' and 'phasing out' each gear. It states that there are complicated electronic and hydraulic controls for this transmission. The 'phasing' of gears on these clutches is fancy speak for saying that the clutches are being slipped in a soft shift, the same as is done in a lazy shifting automatic transmission. It's not that a transmission like that couldn't be fitted to a farm tractor. It's that it's not a practical thing to do, in my opinion for a farm tractor. The reason that the Select-O-Speed (and perhaps some of it's counterparts of that time) didn't work is that it had poor manual controls that resulted in a poor shifting, jerky transmission. It didn't get coined the Jerk-A-Matic for nothing. It earned it. The eliptical gearing of those transmissions was actually pretty reliable. It was the controls that were poor. That's why manual controls don't work well in most cases. The modern power shifts mostly use a complicated mass of speed sensors and modulator valves to control the shifts. Their timing and pressure is that critical that they must be recalibrated in service to compensate for wear over time. It's my belief that it's nearly impossible to get that kind of timing from a manual control system, in a way that is repeatable so as not to destroy the transmission. Think what you like, but planetary transmissions are what's out there today. If this technology had any merit in an ag application, I find it hard to believe that someone would not have done it by now because it could be somewhat more efficient.
We sell tractor parts! We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today. [ About Us ]
Today's Featured Article - Box Plow Blues - by Tom Schwarz. One of the first implements most tractor owners obtain is the box plow. For very little money, this piece of equipment promises to plow and flatten any hill or vale on your ranch road or farm. At least that's what I thought! As simple as a box plow appears, it can be rather challenging to make work correctly. In our sandy soils of Florida, traction is king. You can never have wide enough tires or heavy enough weights to get all the traction you want … unless you own a monster tractor. U
... [Read Article]
All Rights Reserved. Reproduction of any part of this website, including design and content, without written permission is strictly prohibited. Trade Marks and Trade Names contained and used in this Website are those of others, and are used in this Website in a descriptive sense to refer to the products of others. Use of this Web site constitutes acceptance of our User Agreement and Privacy Policy
TRADEMARK DISCLAIMER: Tradenames and Trademarks referred to within Yesterday's Tractor Co. products and within the Yesterday's Tractor Co. websites are the property of their respective trademark holders. None of these trademark holders are affiliated with Yesterday's Tractor Co., our products, or our website nor are we sponsored by them. John Deere and its logos are the registered trademarks of the John Deere Corporation. Agco, Agco Allis, White, Massey Ferguson and their logos are the registered trademarks of AGCO Corporation. Case, Case-IH, Farmall, International Harvester, New Holland and their logos are registered trademarks of CNH Global N.V.
