Correct transmission oil for newer Gravely 12 Professional two wheel tractor

[seacookie]

Recently purchased a Gravely 12 hp Professional two wheel tractor; probably one of the last ones built, but there is no model or serial #'s on the machine. It has only 250 hours on it. I was checking fluids via dipstick which revealed a foamy green oil in the transmission. A downloaded manual and one dealer I spoke to said it should be 10-30 motor oil and another spec indicated 30W motor oil. I drained it thinking there might be water in the oil only to find that the oil is definitely not motor oil I'm used to seeing; it was green and it's consistency reminds me of Red line synthetic high performance gear oil (which is blue not green) used in auto gearboxes in performance cars. Now I'm thinking I shouldn't have drained it. Does anyone know if they changed the oil spec in later years near the end of Production? If so what should it be. Thanks!

 

[js5020]

Gravely bounced around a bit on the oil over the years, but never was gear oil recommended. The old L models had a combination sump for the engine and transmission so engine oil had to be used,, the newer machines don't have the combined sump however engine oil is used, some like 30w, some use multi viscosity, 10w30, 10w40 etc. Get the gear oil out of it ASAP! I forget but one of the additives in either the GL-3 or GL-5 gear oil will eat the brass gear. I run multi viscosity engine oil in mine.

 

[seacookie]

Recently purchased a Gravely 12 hp Professional two wheel tractor; probably one of the last ones built, but there is no model or serial #'s on the machine. It has only 250 hours on it. I was checking fluids via dipstick which revealed a foamy green oil in the transmission. A downloaded manual and one dealer I spoke to said it should be 10-30 motor oil and another spec indicated 30W motor oil. I drained it thinking there might be water in the oil only to find that the oil is definitely not motor oil I'm used to seeing; it was green and it's consistency reminds me of Red line synthetic high performance gear oil (which is blue not green) used in auto gearboxes in performance cars. Now I'm thinking I shouldn't have drained it. Does anyone know if they changed the oil spec in later years near the end of Production? If so what should it be. Thanks!

Thanks for the info. Now that you mentioned brass in the trans reminds me of similar concerns with my 1972 MG trans which calls for 20W50 motor oil. Unfortunately modern oils contain significant increases in additives which are believed to damage the brass components. Recommendations form MG trans gurus suggest using non-detergent 30 weight oil to avoid this problem. Since the specified 10W30 SF has now evolved into SN or SM spec should Gravely owners be concerned in using the new engine oil formulations?

 

[2manyrocks]

In looking at the professional manual, it only says use 10w30 in the transmission, but doesn't give a spec for the oil unlike gravely manuals for earlier machines which actually gave a spec for the oil. http://gravelymanuals.com/pdf/Prof_2_Wheel_Trac_OM_1087.pdf

 

[RalphVa]

My 12 hp Gravely (think it was a 5665?) took 10w30 motor oil in the trans. If I had it now, I'd use 0w30 or 5w30, better for cold weather and fuel economy, as it'll be lighter on startup but same as hot operating temperature.

Ralph