Hydro Gear 314-0510 grief & solution?

My Husqvarna LTH1742 has the near famous or infamous(???) Hydro Gear 314-0510 hydrostatic transmission. Up to recently it was working fine, but started to be a pain when going from neutral to very slow forward (the tractor did not move), the tractor would eventually jerk ahead at mid speed and continue forward. If the lever was moved back to slow speed, no forward motion would happen. Reverse was okay in all positions. I reread the manual (available online at husqvarna.ca) and tried purging the transmission. Voila!!! It worked. The tractor crawls forward slower than a racing slug which is great for mowing around trees & bushes. Hope this post helps someone.