A friend that has a 07 Craftsman 22 HP has a hydrostatic trans that is done. He is wondering if there is a way of servicing it as it is sealed or look for one that he can purchase. Any ideas would be appreciated. Thanks
I was told by a repairman that they aren't field fixable.
That's typical in my experience of a worn out HST, as soon as the oil gets warm it stops producing motion, or stops producing enough motion to be useful. You can look under the back at the able and you'll see a white sticker that will tell you what it is, like on my Craftsman it has G730 on that part number sequence, telling me that I have the Hydro Gear G730.
Once you know what you have (it's obviously not a G730, as it has a spin on filter and is serviceable) you can Google that axle model and see what price hangs from it.