MrFixAll

Here is what I did to fix my Craftsman mower tranny. I drilled and tapped a #10 hole in the right rear bottom/side of the case to drain out the old fluid and put in a short machine screw to plug the hole. I emptied the recovery tank and refilled the trans with Carquest Premium Tractor Fluid. I filled the recovery tank about 1/3 full. This all took about 2 1/2+ quarts total. The hardest part was bleeding out the air from the system. I did as instructed in the owners manual several times, waiting about 20 minutes between trials. Also pushed the tractor while the tranny was engaged until resistance was felt and after some time the air was out and the tranny works like new now. I recently had another apart that only needed a 65 cent spring to get it going, but again the hardest part was getting the air out of the system. Good luck!  MrFixAll Update 4/30/08, I just finished repairing my HYDRO-GEAR trans again. It was making a snapping noise with severly reduced speed. Once again I drained out the fluid from an access hole that I made earlier, disassembled the trans, (see owners manual diagrams), and found another broken spring in the Block Assembly. There are a total of 10 springs in two block assemblies in the trans. (The block assemblies pump oil). The springs cannot be purchased from manufacturer, only the block assemblys. The springs I use are from the hardware store and now cost $.75 and are similar enough to work well. (My last repair on this trans lasted almost 2 years and the spring that was replaced is doing fine.) This time, during re-assembly, I filled one case half with oil before attaching the other case half. After assembly was complete, I finished filling the trans, (remove top plug with allen wrench), and now with trans filled with the recomended 20w-50 oil, I then filled almost full, the resevoir and installed it on the tras and installed the trans in the tractor. This time the transmission worked great almost immediately. Good Luck ! ( See http://www.m-and-d.com/Hydro-Gear_parts.html )