View Full Version : Grasshopper 721D - Oil changes and the such

06-10-2007, 12:53 PM
I just picked up a Grasshopper 721D from a city surplus auction ($3100...did I pay too much?). Overall, it looks ok, sounds strong, and the hydros seem strong. It has 1057 hours on it.

My question is what kind of recs does anyone have as far as type/weight of oil in the hydros and engine? I want to change all fluids and filters so that I know the status of everything.

Thanks for any input..

06-10-2007, 01:01 PM
You may order Tractor and Deck Operator's Manuals, including service and parts, from grasshoppermower.com.
Or, you can order them through your local dealer.

XB 2002
06-10-2007, 06:58 PM
The Hydros require Grasshopper Fluid ( $$$ ) or Mobil DTE 26. I bought 5 Gallons from a Mobil Distributor in my area for about 40.00 Bucks a few years ago. I Used Shell Rotella ( for Diesel engines )If the hydros are strong you made good deal if the rest of the machine is in decent shape. The 21 Horse Kubota is about bulletproof. It will out last the rest of the machine. Good Luck.
XB 2002

06-10-2007, 09:16 PM
Thanks so much for the info so far.

I will order the manuals from the website on Monday when they are open. I will go shopping for the Mobil and the Rotella is the same thing I run in my truck.

Any additional suggestions on filters (oil, hydro, fuel)? Does everyone just buy them from a dealer or are the aftermarkets?

Another question...how can you really test out the hydros? The machine goes forwards, backwards, and turns fine. No squealing, noises, etc. And it seems to run at a darn good speed. This is the first ZTR I have ever driven so I have nothing to compare to.


XB 2002
06-10-2007, 09:28 PM
When my hydros were going bad, I would notice a difference in the performance after it got hot. If you run it for 30 minutes and it still has good power in both forward and reverse I would'nt worry about it. I would stick with the Grasshopper Hydro filters and use whatever you like for the Kubota. The hydros are a all in one Gemini Transmission and is about 700.00 a side to replace. You may have the G2 Trans which I think has separate pumps and wheel motors. If you don't hit curbs or jam the controls from front to back real fast and change the Hydro oil regular it will probably last a long time. Good Luck
XB 2002

06-10-2007, 11:01 PM
If you have a 721D, you have the Gemini transmissions. Those now cost about 1000.00/side to replace, or more. Use the DTE fluid in those. If you have a 721D2, you will have the separate trans. and wheel motor setup. Use the Grasshopper synthetic oil in those, or an equivelant synthetic oil.
Do not try to save money on the hydro. oil filters. Use the Grasshopper filters. On the engine, you will need to take the fuel filter and oil filter with you to a Kubota tractor store, as they can not usually look up the part number for that Kubota engine. That is a Kubota "industrial diesel", not a "farm diesel". Usually, only a Kubota industrial diesel service and sales center can match the part numbers. However, a Kubota tractor store will be able to match one of theirs to the one you take in.
To test trans do the following. Drive machine up to a steel post and have the machine sitting on concrete. Push the machine into the post with each drive lever and see if each side spins the tires hard on the concrete. Both sides should perform about the same and trans. should spin tires. If either tire does not spin, you may have a problem somewhere. Most common problem is belt tension on the hydro drive system. If you suspect a weakness in either side, check belts, tension idlers, idler arm pivots, and idler arm springs first.