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Wes: Welcome to the club! Kent's description and explanation of the transmission is right on. I have a 312 and have also experienced the tractors' inability to roll forward with the engine off. When this happens, I stand behind the tractor and with my left hand, reach down and lift up on the brake band slightly. This usually releases the brake and I can push the tractor forward. Hope this helps. Best of luck. Pete
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found your club a few days ago and am still exploring. this is a great site and has a LOT of good info. i have an old AC310 that is not running,but i think it will. i have a small problem right now in that i don't understand how to operate the transmition. all the placards or decals have been weathered away and the only one i can read says" do not move this lever with-out the engine running". well, i can only push it around the garage backwards- it won't roll forwards. if anyone has any info on this particular tractor, or an opinion, too, i would appreciate it. thanks.
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Wes, Dunno why it won't roll forward.... But, you have a Vari-Drive transmission that uses two variable speed pulleys on a standard 3-speed transmission to give you 7 variable speeds in each gear range(1,2,3 or Reverse) for a total of 21 forward, 7 reverse. That's the lever with the label you're referring to. With the engine running, you must have the clutch/brake pedal fully depressed (to stop the drive belt from turning) to change from one speed range to another (1st to 2nd, for example). Then, once you're rolling, you use the Vari-Drive lever to "fine-tune" your ground speed to match what your job/attachment demands. For example, I do all my mowing in 2nd gear and use the Vari-Drive to adjust my ground speed to handle taller/thicker or shorter/thinner grass, leaving the throttle (and engine RPM and blade RPM) constant at between 3/4 to full throttle. I till (or will, if it ever stops raining) in 1st gear and use 3rd only for transport... Example of how it works mechanically: when you move the lever forward it pulls the front (cross-drive) pulley halves closer together forcing the belt higher in the groove and the back (transmission) pulley halves further apart, allowing the belt to go deeper in the groove. You've just altered the "gear ratio" by doing this since for every time the engine turns over the front pulley turns the belt further and the rear pulley spins the transmission faster.... Move the Vari-Drive lever backwards and both pulleys reverse the above description, as the belt drops deeper in the front pulley and rides higher on the rear pulley, lowering the "gear ratio." The reason you're not supposed to move the Vari-Drive lever without the engine running ((you actually could be (1) rolling under power or (2) parked with the engine running, the transmission in neutral and the clutch out)) is that the both the front and rear pulleys must be turning at the same time to allow the belt to gently move up/down in the appropriate pulley -- it moves up/down in both at the same time, just in opposite directions. Otherwise, you'll either pinch the belt or bend/break something as you force things.... Remember the clutch stops the belt, which stops the back (transmission) pulley from spinning! Further, if the rear (transmission) pulley is spinning (i.e. not fully clutched) when you try to change from one speed range (1st to 2nd, or 2nd to Reverse, for example) you'll grind the gears -- this is an unsynchronized transmission. You must stop stop the belt from moving, stopping the back pulley from spinning, to change speed ranges. A better label for this Vari-Drive lever might be "Don't move this lever with your foot on the clutch!" Hope this detail hasn't confused you more... Also hope someone else might have a clue on why it won't roll forward but will roll backwards....
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Welcome,I also own 310,They are great tractors when they are running but some parts are a little tricky to find.When I got on this sight I had a bad carb,the wires on my alt. were gone and I had no Idea on the history of my tractor.Thanks to the people on this sight I now have a fantastic running tractor.This club is a great resource,good luck with your project. Jim V
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