Which Transmission oil for JD 790??

2kpsd · Oct 28, 2007

I just changed my oil for the 2nd time and also am going to change the transmission oil and filter. When I was at the John Deere parts counter they cound't figure out which trans oil to use regular HyGuard or the Low-Viscosity stuff. They decided on regular HyGuard since my tractor is not a hydrostatic trans. Today when reading the owners manual it says to drain fluid, etc. etc. and refill with the Low-Viscosity fluid. What do you think I shuold do? Go get the low viscosity fluid or use the HyGuard trans oil they sold me yesterday?? Thanks in advance- Tractor is a 2006 John Deere 790.

Soundguy · Oct 28, 2007

2kpsd said:
I just changed my oil for the 2nd time and also am going to change the transmission oil and filter. When I was at the John Deere parts counter they cound't figure out which trans oil to use regular HyGuard or the Low-Viscosity stuff. They decided on regular HyGuard since my tractor is not a hydrostatic trans. Today when reading the owners manual it says to drain fluid, etc. etc. and refill with the Low-Viscosity fluid. What do you think I shuold do? Go get the low viscosity fluid or use the HyGuard trans oil they sold me yesterday?? Thanks in advance- Tractor is a 2006 John Deere 790.

I'd put in what your manual specifies, unless the dealer is going to handle any waranty problems that -could- arise from a non specified oil.

soundguy

DieselPower · Oct 29, 2007

Most John Deere's spec either in the manuals I have read. Usually calls for the low viscosity in colder temps and regular HyGuard in warmer weather. Check the fluid specifications section of the manual and see if there is a page that list different fluid spec's for different operating temps.

crashz · Oct 31, 2007

I drained & filled my JD 770 with new Hyguard and I could have sworn it also said low viscosity as well. Isn't all of the new JD Hyguard the same?

DieselPower · Oct 31, 2007

My understanding is at one time there was HyGuard and LoGuard. They changed the LoGuard name probably because that just didn't sound to good (as in low quality or something). They now call it low viscosity HyGuard which as far as I know is still available. Many lubricant manufacturers offer a normal UTF and a low viscosity/low temp UTF oil.

Brimstone10x · Nov 9, 2007

dont lose any sleep over the hygard / lo vis hygard in the 790 so long as your not at the north poll or death valley. eather one will be just fine. its like 10w30 virs 5w30.

2kpsd · Nov 11, 2007

Ok so yesterday I finally made it back to the JD dealership I originally bought the fluid from and they traded it straight across the counter for the Low-Viscosity Hyguard. Go home, drained the transmission fluid and it came out red in color like most trans fluids. Got it all drained out, removed the external filter, put the new filter on, poured in the new low-vis fluid. It came out tan/oil colored. So red fluid drained out and tan fluid went back in. On the dipstick to check the fluid the back says use low-viscosity only. So I guess I used the right fluid but from the factory did someone put the wrong fluid in it from the beginning??? My tractor's warranty expries April '08. I would hate to have something fail due to this.

DieselPower · Nov 11, 2007

Never go by fluid color, it's only a dye. One manufacturers low viscosity may be amber, the next green, the next red, etc..... Same goes for any lubricating oil or grease, color means nothing. It's just a dye put in by the manufacturer and red is a popular color.

kennyd · Nov 11, 2007

If the fluid was red, it has been in there since it was built. Yanmar uses red fluid we they build them, it's easier to spot leaks. It sounds like you got the right stuff