John Deere 770 hydraulic fluid change

[Mattyboy93]

Hi guys, new to the forum. I’ve owned several John Deere lawn and garden tractors but recently purchased a John Deere 770 2wd w/power steering. It’s my first diesel ag tractor. I dont think the previous owner did much maintenance on it. So I decided to do do an all around change. Got everything done but the hydraulic fluid done and it may be a dumb question but I see the (I think plug) with the 3 bolts that you remove to pull the screen... but is that the main drain plug? Or is there another one? I know some ag tractors have several drains but does this one? I have a service manual on order but figured I’d check here.

 

[beenthere]

:welcome: to TBN

Put up a larger pic or two before zooming in, and a couple arrows to help orient us on what you want us to see in the pic would help.

Attached is a schematic of the tranny, and shows the 3 screen bolts you refer to as well. There is a 1/2" drain plug in that cap.
Also, here is another TBN thread that shows other drain plugs to get more hyd. oil out.
https://www.tractorbynet.com/forums/john-deere-owning-operating/4017-drain-plug.html

Glad you found TBN. You will like the 770.

 

[Mattyboy93]

I apologize I reposted some pictures to show what I’m looking at. Picture 1, Circled in red is the hydraulic screen and the center bolt is the main drain plug? Picture 1, circled in blue is that 1/4 set plug.. is that a secondary drain?

Picture 2, circled in blue is a close up of the screen cover (3 bolts) and the square plug (center of cover)

Is that plug on the screen cover plate the main drain for the hydraulic system or am I supposed to be looking for a different plug?

Picture 3, circled in red is a close up of the 1/4” set plug.

Reason I’m asking about where all the drain plugs are located is because I was debating on draining the old, sealing it up pouring in a little kerosene In the case and sloshing it around a little and drain out any crap that might be in there. Then let it open over night and refill the 4 gallons with the hygaurd.

 

[Mattyboy93]

From looking at that topic you sent me about the JD 670 (similar to mine) there is 4 plugs? The screen plug, that 1/4” plug, and two on either side. Would that be the general consensus?

 

[beenthere]

Would that be the general consensus?

Yes, think you have it.. thanks for the extra pics and the circled parts. I'd suggest the "either side" plugs will drain the tranny the best.. appears they are lower in the system. But removal of all of them to be sure they will drain should give you a good idea how much sludge is there, if any.

Enjoy the oil change.. will feel good to have it done as then you know it's all good.