Since I'm doing my 50 hour I needed filters and of course neither the owners manual or service manual had the part numbers for the filters so I had to drive to Yuba City to buy them. I thought I'd share the part numbers here. I have a 1538 gear or shuttle so the hydraulic filter may be different for the HST tractors, I don't know.
The hydraulic filter is really a Mitsubishi made filter the part number is 19642509000. I stopped by my local NAPA store and the NAPA equivalent is 7118. I paid $38.14 at the Mahindra dealer, I think this is cheaper than what NAPA wants for theirs.
The fuel filter elements of which there are two is part number 001081778R93. The NAPA equivalent part number is 3993. I paid $11.43 each and they look like they are worth maybe 50 cents if that. The Mahindra filter is very poorly and shoddily made of cheap materials. I'll be replacing that with an equivalent from NAPA next time for sure.
The engine oil filter is 006000789B91. I couldn't come up with an equivalent for that because of the oddball thread pitch used. I paid $14.71 for it so no biggie. Outside of the odd ball thread pitch, it's a nothing special filter with no anti drain back valve etc.
My guess would be that the 1538 and 1533s use the same filters as they have the same engine.
BTW when I first called the NAPA store, their computer didn't recognize any Mahindra 1500 series models so without these numbers they won't be able to help you.