Sorry to revive this OLD thread, but I am in the process of doing my 50 hour service on my B3030 right now.
The 2 trans filters have different part numbers, and are slightly different "sizes" (looks like length is only difference). My parts guy at the local dealer labeled one of them as the HST filter. However I don't know which one is which as far as where they go on the tractor!
The only thing I can think to do at this point is match the size of the ones I am taking off the tractor. The one on the right side is oriented front to back (the axis of the filter aligns with the longitudinal axis of the tractor) and is attached to a fitting with a tube coming out of it and going to what looks like a pump beside the engine. The other filter screws into the side of the transmission case on the LEFT side of the tractor with a cast-in fitting location similar to what you see on an engine block.
If I match the SIZES of the filters, the one that screws in on the LEFT side, going directly into the transmission CASE is the one he labeled "HST" and is part number 66021-36060 (it is blue). The one that matches the one of the right side of the tractor is part HH670-37710 and is grey in color and a bit longer.
Can anyone help me?!?!?!?!?!
Thanks,
Steve