I agree...$5000 on real commercial machinery repair/rebuild is nothing. This is the main reason I haven't bought a Bobcat excavator. Fantastic machine but too expensive for my non-commercial use. Better to just rent.
The PT wheel motors are a known commodity. Search the forum for details. The displacement and style varies slightly depending on the year of your unit (e.g., 12.5 cu. in. vs 14 cu. in. if memory serves). If you really can't find anything, post back and we can help.
As to your pump wear, that sounds abnormal to me for a PT with that many hours...in that you got MANY more hours than I'd expect. PT considers these pumps a wear item. I think I read somewhere that a pump should last about 4000 hours on average in optimum conditions. That's not what we should expect. I've had pumps repairs at <700 hours and <500 hours on different machines. My neighbor had his pump repaired at about 1000 hours but it was weak for a long time prior. The PT filtration setup is far from optimal. Ideally, it would have multiple filters in the hydraulic circuit...like Kubota uses in many of their machines. For example, the whole pump/wheel motor circuit is closed and NEVER filtered. In theory, the oil is gradually replaced by the charge pump over time but this varies by machine type (e.g., 425 has no dedicated wheel motor case drain; 1845 does).
In any case, I've stopped worrying about it. Everything's a compromise. If the filtration was better on the suction side, cavitation potential would be even higher on cold start ups. The overall machine design is awesome. So, I now consider the cost of a pump rebuild as "normal" so it doesn't hurt so much. Kinda like my wife's hairdresser bill.
Regarding the engine, the Robin is terrible in my opinion. The old Kohler's were great and I still have some on other equipment. They start good and seem more tolerant of high operating temps. Personally, this is the one area where I think the benefits of synthetic oil is justified....air cooled engines.
Good luck with the rebuild and try to take some pictures. I know it's difficult to take pictures when working on machinery ("I just want to get it done"). But we all like pictures. I'm about to get started again with the rebuild of my 425. I just ordered a brand new BP pump all the way from Italy as a spare ($1900). I have a rebuilt pump I'll throw in for now. I'm using a Subaru (i.e., Generac) 35 HP engine. I'm also using higher capacity wheel motors for more torque. I can't stay on the PT at full speed on my property anyway so I'll trade speed for torque (I might not if using the machine commercially where time is money). Personally, I like to see the wheels spin when pushing into a pile of dirt with the bucket.
