Hydro Transmission Fluid Level

Steve656 · Mar 26, 2013

I have a 656 Hydro. While reading this forum it has been stated that you check the transmission fluid level with the tractor running. My owners manual dos not mention having it running. To further complicate this I have a loader on the tractor and the return line goes into the oil check port. They plumbed it in and then put a cap on it and brazed a dipstick to it. Tried checking the oil with it running BUT when you take the cap off all you get is fluid pouring back in from the loader "circuit". I wonder what level I should see with the tractor not running??? Thanks for any input.

pete 23 · Mar 26, 2013

When the engine is shut down the oil returns out of the hydrosatic drive section slowly. This section is normally completely full when engine is running. So, if you check oil level shut off the dip stick will read way over full. If you shut it down and check it right away you will have a pretty close check but you will have to be pretty fast and probably do it a few times running it for a few minutes and shutting down to establish a reliable reading. It is supposed to be checked after engine has run a few minutes and while engine is still running, but if you cannot do that then you can't. I would not recommend returning oil into that filler port though as it will cause aeration and that is second worse situation for a hydrostic transmission behind dirt. The normal return flow from the aux valves on all the 656 series is directly back into the suction tube in the rear end. If it is impossible to use one of the aux valves to return oil I would at the very least return it below the oil level in the rear to minimize airation.

TJV · Mar 26, 2013

if its like our 186 hydro it will be way over full (1-2 inches on the dipstick) before startup since alot of oil has drained out of the trans parts and into the rearend. when running all of those cavities are full of oil. if i remember correctly it says to have the tractor running at 1500 rpm for 5 min before checking right on the dipstick and in the book.
just another thought is there a way to shut off the flow to the loader so it can be checked running and not have the return oil flowing in your way?

Steve656 · Mar 27, 2013

Pete I understand what you are saying about aeration and I also understand that the transmission fills when the engine is running and therefore the need to check it while it is running if at all possible. I am also wondering why there is not another line on the dipsticks that would show the level when it is cold?? The second comment suggests that it is a couple of inches higher on his dipstick when his machine is cold so why not just have another line on the stick?? Not knowing a heck of a lot about this myself I am hoping one of you fellas can explain it to me???
Thanks again for the help.

pete 23 · Mar 27, 2013

I don't know why they did not put another line for reading when shut down. Probably be pretty easy to do once you figure out where you are at with reading stick when just shut down.

Hydro Transmission Fluid Level

Steve656

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pete 23

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TJV

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Steve656

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pete 23

Well-known Member

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