Oil & Fuel JD 790 - can't find the drain plug

[katesaidan]

Got all motivated and bought the oils for the hydraulics, engine and front axle. The tractor we have just went over 500 hours (512) so it's due for all this servicing.

Using the S/N I looked up the manual on how to change the hydraulic fluid but the drain isn't where it's supposed to be?

This is what it's supposed to look like but this doesn't exist on the underside of my machine.

This, however, is exactly as pictured in the manual.

I need to get this done and I'd rather drain it from the plug than pull off the filter... Does it matter? I already have the new filter.

 

[diesel466]

The top picture is of a machine with a mid pto, Do you have one on your tractor? The drains should be on the sides of the axle housings. They should have some yellow paint on them.

 

[katesaidan]

I have only the rear PTO. I crawled underneath and saw a LOT of bolts, none were yellow. And I don't think I'd know what an axle housing was if it bit me on the butt.

 

[RoyJackson]

There have been three revisions to the 790 (not including the 3005). The picture below is from the later two manuals.
This link (hope it works) takes you to the manuals page:
790 Manuals

Here's the picture. The drain plug is "A", the screen is "B" and "C".

Hope this helps... (BTW, have a good sized pan under the drain...that's about 5 gallons coming out if I recall correctly)

 

[katesaidan]

Excellent! Okay - now I'm going to sound really dumb. The string of numbers after the model name is the SN range, right? I was in the manual for my SN, which is apparently not right.

This picture is excellent, thank you. And yes, I have many pans to catch fluids. This particular machine is 4 gallons.

 

[RoyJackson]

Excellent! Okay - now I'm going to sound really dumb. The string of numbers after the model name is the SN range, right? I was in the manual for my SN, which is apparently not right.

This picture is excellent, thank you. And yes, I have many pans to catch fluids. This particular machine is 4 gallons.

It's the numbers in parentheses.
Deere (or Yanmar) wasn't always up to speed when revising their manuals.
FYI, the tractor's serial number will be on a plate just above the rear PTO shield.

Good tractors, the 790. I had one for about 6 years. Only thing I didn't like about it was reverse gear...low being too slow, high being too fast (when at PTO RPM).

 

[AKfish]

I need to get this done and I'd rather drain it from the plug than pull off the filter... Does it matter? I already have the new filter.

Please drain everything before you attempt to change the filter! You'll have ALOT more oil gushing out than you'll likely have containers! It's not a pretty sight...

AKfish

 

[RoyJackson]

Please drain everything before you attempt to change the filter! You'll have ALOT more oil gushing out than you'll likely have containers! It's not a pretty sight...

AKfish

I think he was only considering draining from the filter because he couldn't find the drain plug location.
I think he's squared away on that and lived happily ever after...

 

[Henri88]

Please drain everything before you attempt to change the filter! You'll have ALOT more oil gushing out than you'll likely have containers! It's not a pretty sight...

AKfish

You sound like a ''Been there done that'':laughing:

 

[katesaidan]

I'm a "she" actually. And my tractor is my new favorite toy!

I was considering pulling the filter off only because I couldn't find the drain plugs. Found the drain plugs, not quite happily ever after. I had a wide pan under the transmission to catch the oil, unfortunately when I pulled the plugs the oil drained out with enough force that it was spilling all over the wheels for the first few minutes. I thought about calling BP for advice but decided instead to just dump about 20 lbs of cat litter on the spills in the driveway.

The BEST part (aside from having to wash my hair with dish soap after my hair dipped into the transmission oil in the driveway) is that my clutch is not nearly as jerky as it was before. I put it into second gear and didn't get whiplash when the machine went forward. Score for me!