I intend to change the Transmission oil of my 1988 Champion 720 Motor Grader, transmission model is 8400. Despite not presenting any noticeable problems, I want to change the oil as the previous owner sometimes filled with ISO 68 hydraulic oil instead of Dexron II as indicated in the manual. I've only seen foam through the level gauge when it starts up. Considering that the oil is contaminated, I intend to change as much as possible that is in the system, which according to the manual is 53 liters and I will put ATF 220 from Mobil, which is the oil with the Dexron II name available in these neighborhoods. I would like to know if there is any procedure other than removing the drain plug and waiting for the last drop to fall and putting the new oil up to the middle of the level indicator. Is it done with a hot or cold engine? Is it necessary to prime the system before starting the engine? I appreciate your advice. From Chile, South America, Cesar
Is there a torque converter? if no torque converter, then I'd run it until fully warmed up, and run it through all gears, then drain it hot as soon as you shut off the engine. Refill and start it immediately. Are there any filters and/or screens to change at the same time?
is there a screen in the bottom? Can't remember. No torque. Clutch is separated from the transmission by an external driveshaft. Although that was in a 730.
I’ll check my book tomorrow but I remember a screen as well.
Indeed it has a suction screen, at least that is what the manual says, it is located inside the transmission where the oil outlet hose is connected. There I also have a doubt because according to the lubrication chart this suction screen is changed at 480 hours but the oil changes at 900 hours ... How could I change this part that is located in the casing of the transmission box, are all the oil to come out ??? But that is only a small question and this time I will drain all the oil so it is not relevant either. My main interest is to know the recommended procedure to change the transmission oil and filter, draining as much old oil as possible and to know if later it is necessary to prime the pump so that everything works normally. Thanks Cesar
I don’t remember a screen. The drain plug on the 90 I ran had 3 (possibly 4?) magnets in a row spaced out by springs on the drain plug. The suction hose takes something like 2 1/4” wrench and the only time we ever had that off was when swapping transmissions. Filter was a #53527 I think. We changed that every 500 hours and oil every 1000.
@Fatgraderman Thank you for telling me your experience. Do you remember if it was necessary to prime the pump after changing the oil? I am thinking that the large suction hose will be dry when it loses the oil due to gravity, so I do not know if when starting the engine it will be able to suck the oil from the transmission crankcase.
We never did. I’m not sure how you would on that. That one is the earlier setup that had the transmission pump built into a 2 sided pump that was under the radiator. Most that I ran drove the pump off an accessory drive on the bellhousing. But I know the first 730 (90 or 91) drove the hydraulics off the bellhousing and they used a stacked pump off the crankshaft, one side for transmission and one side for steering maybe? Your manual says Dexron for the transmission? We initially used 10w and the machine that sat outside in the cold got 0w40.
Seems to me the old screamin detroits had automatic transmission fluid. Not sure when the went to cummings. My old 730 had 10w, it was a 1990