AndyMark shifter Dog Gear screw problem - lower your pressures

[Andy Baker]

All,

This past weekend, we were informed of an issue by three different customers. The M2.5 screw within the 2010-2011 AM Shifter and Super Shifters are breaking at a rate higher than expected.

The initial fix for this is for teams to lower their shifting pressure from 60 psi down to 35 or 40 psi. Many teams already run at this lower pressure, to reduce wear on the shifting parts.

During the years of 2005-2009, we used a 3/32" coiled roll pin (heavy duty) to attach the dog gear to the shifter shaft. This past summer, we replaced this roll pin with a M2.5x20mm hardened screw. While our break tests proved that the same amount of force broke both types of pins, it seems that the screw does not handle fatigue as much as the roll pin.

The simple fix for this is to run your shifter at a lower pressure. A 3/32" hole can be added to the dog gear, in order to accommodate a 3/32" roll pin, if you wish to add this pin.

We will be doing some more testing on this, determining what exactly is going on. I just wanted to let folks know that this is going on, and they may want to lower their shifting pressure.

Keep in mind that the shifter shaft position should still be set up so that the small brass "pin saver" tube is in place so that the dog gear does not bottom out on either the full low or full high end of the cylinder stroke.

Once we know more about this, I will post the info.

Sincerely,
Andy Baker