Gene,
Be sure to search this forum on the word: filters, and you can find some cross references to wix filters. Also note that it has been reported that the Branson hydraulic filter seems to work better (less restrictive of flow) than the alternatives. So, I recommend staying with the factory filter. Be sure and clean out the debris screen on the transmission also.
I was very confused about which fluid to use, and I defaulted to the most expensive at our local supply store. I later visited a TSC store some 50 miles away and they were selling a transmission fluid for around $30.00 per 5 gallons. I had paid $45. You'll need 15 gallons to include the front axel. I had also read a post about allowing a second source of air when filling the transmission. I had a lot of 'burping' to do.
This forum has been a great source of information.
Jim
3820i, BL50A FEL, 8620 BH