I am at the 500 hr service interval on my 4300 and my dealer recommended replacing the transmission filter and cleaning the suction screen but he said there is no need to replace all of the fluid. I could imagine swapping out the spin on filter w/out draining the fluid first but is this possible with the suction screen. It is at about the lowest point on the transmission housing, which makes sense for filtering purposes, but I would imagine you would have to drain all the fluid first or it would just drain out of the suction screen passage when you remove it. I guess he might have meant that I should drain the fluid and then reuse it after the filter/suction screen service but this does not seem like a good idea either. Any help is appreciated.