Small Engines (Lawn Mowers, etc.): transmission slip ayp, technical service staff, expansion chamber

Question
960160004 poulan pro/ayp with hydro gear 314-0510.
I changed the belts because I started to feel a decrease in speed while going up a small incline.  No increase in speed after belt change. I would like to check/change hydro oil. Mower is 3 yrs old.  I have the schematic for 314-0510 and part #109 is the plug. OK, how do I drain old oil? Does transmission require removal for oil change?

Answer
Most units do not require that you change oil in the transmission.  There is usually an expansion chamber under the hood.  It is a small round container usually clear with a black cap.  The purpose of this is that the oil expands when it gets hot in there has to be room in this chamber for the oil.  If the oil is milky in color it means there is water in your oil.  Usually there is a mark for hot operation and cold operation on the chamber.  Be sure the oil is to that level.  At hydraulic powered tractor slowing down usually means there is a pressure loss in the transmission.  The only way to fix it would be tearing down the transmission and inspecting the charge pump.  You will probably find small scratches on the plate but pump rotates on.  With the unit only being three years old I would talk to the manufacturer and they may be able to help you will.  Pedro gear is in Sullivan, Illinois and they have a fairly complete website.  I suggest using the website to contact them with all the role of and information.  Their technical service staff should get back to you.  Hope this helps.