steigerpower - 4/15/2009 23:01

On the high range not holding--

I'm pretty sure the ST-310 is a 20 spd like my series 4 tractors, the inside range lever is the transmission range, the outside range lever is the transfer case.  The transfer case range lever and linkage do not provide enough travel to fully shift from one detent to another after things get worn out.  On my tractors, you have to get under the tractor and manually push or pull on the transfer case shift rod to be sure you have it locked in gear.  You should be able to "feel" the detent ball lock in.  If you can't feel it lock in to place, you may need to work on the detent ball/spring.