Mowing 07 John Deere 757 ZTrac Pump Problem

[willy t]

I purchsed a 2007 John Deere 757 ZTrak used from a landscaping co. he told me it had a new pump & left wheel motor put on it recently.When I started using it in early spring,it couldn't get up a hill,very weak on left side control,took it back to him,had it 2 months,said put some seals in it & was working good. had it 2 weeks,now its so weak won't hardly move at all.I know now they have issues with this pump(Kanzaki DUP 10s) John Deere wants a fortune for one, any quick fixes or rebuild kits out there I can't find anything,appreciate any suggestions thanks