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Hydrostatic trans on John Deere 316 needs help

8K views 15 replies 4 participants last post by  JDW 
#1 ·
I have a John Deere 316 tractor that has sat unused for 4 years. I got the Kohler motor running but when I try to go forward the unit bucks very badly. When I move the lever to reverse the tractor doesn't move. I am able to push the tractor without too much trouble which makes me think a valve is stuck open. My problem is I don't have any idea what valve or how to correct this problem. Can anyone tell me what to do to correct this transmission problem short of throwing it away and purchasing a new one "IF" they are even still available.

Thanks for your help. JD
 
#2 ·
Welcome JD! The bucking with no reverse makes me wonder if the rear end is loose in the chassis, either from loose bolts or cracked frame, throwing off the adjustment which takes out reverse, and causes it to buck in forward due to things shifting. Check all that, then get back to us.
 
#3 ·
The trans and rear axle are solid in place, no movement I have removed two valves in the top of the trans unit and can barely see and trans fluid in there. The resevoir in the rear is full of trans fluid so it looks like the fluid is not getting pumped up to the front of the trans unit. My description is poor because I don't know the correct terminology......sorry.

The previous owner said the engine ran fine and the trans worked fine when he parked it.

If I am able to push it around it seems the hydro unit is not engaged ?????????

I can't push my Cub Cadet unless I pull out the lever to release the trans so it will roll easily. This JD rolls easily enough without doing anything. JD
 
#4 ·
Is the fan spinning when is engine is spinning? The roll pins in the drive shaft are know to break, and can cause some funny drive issues

Is filter clogged? The filter can be cross referenced and purchased from the local auto parts store?

Are the pins in the two valves on the top of the trans sticking up? if they are down the whole way or partially, it won't drive right.
 
#5 · (Edited by Moderator)
Yes, the fan is spinning when motor is running.

I have not changed the filter so I don't know if it is plugged or not. I have a new filter and hydraulic oil so I guess I should change that next.

The "pins" in the two valves on top are completely UP when the knob and plate are removed. The pins move freeley. I had both those valves out, checked for movement or clogging, both looked OK.

My understanding is that if both pins are depressed, that allows the tractor to be rolled somewhat easily. This tractor rolls with the pins completely up or down. The pin/valve location seems to make no difference. When I had these two valves out I could barely see any oil down below the valves. It seems to me I should be seeing hyd oil in that area, shouldn't I??? The dip stick fill tube shows the fluid level to be full. Why would the dip stick show full yet the valve area be low? What keeps the hydraulic oil from getting to the valves? Could the pump not be working properly? Is the pump impeller made from hard rubber as in boat fresh water pump impellers that when left sitting get hard and then don't create good pull when spinning?

Attached ( I think ) is a picture of the trans and differential if that helps any.

Thanks to those who are trying to help me. JD
 

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#7 ·
The pump is located just below the two hydraulic lines where the drive shaft comes into the trans, correct? I guess I just disconnect the drive shaft and remove the two bolts that hold the pump in place, correct? Do I need to drain the trans fluid before I remove the pump?
 
#8 ·
The pump is located just below the two hydraulic lines where the drive shaft comes into the trans, correct? I guess I just disconnect the drive shaft and remove the two bolts that hold the pump in place, correct? Do I need to drain the trans fluid before I remove the pump?
Yes on location, and removal. No need to drain oil. The seal under the housing is an o-ring, which should be re-useable.
 
#11 · (Edited by Moderator)
Yes, the fan is spinning when motor is running.

I have not changed the filter so I don't know if it is plugged or not. I have a new filter and hydraulic oil so I guess I should change that next.

The "pins" in the two valves on top are completely UP when the knob and plate are removed. The pins move freeley. I had both those valves out, checked for movement or clogging, both looked OK.

My understanding is that if both pins are depressed, that allows the tractor to be rolled somewhat easily. This tractor rolls with the pins completely up or down. The pin/valve location seems to make no difference. When I had these two valves out I could barely see any oil down below the valves. It seems to me I should be seeing hyd oil in that area, shouldn't I??? The dip stick fill tube shows the fluid level to be full. Why would the dip stick show full yet the valve area be low? What keeps the hydraulic oil from getting to the valves? Could the pump not be working properly? Is the pump impeller made from hard rubber as in boat fresh water pump impellers that when left sitting get hard and then don't create good pull when spinning?

Attached ( I think ) is a picture of the trans and differential if that helps any.

Thanks to those who are trying to help me. JD
The 'rockshaft' is also the shaft for your deck lift. One end of the cylinder is hooked to it.
 
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#13 ·
I removed the filter, it seems OK but can't tell anything about the deep down inside area.

Removed the pump, the pin is OK, and the other parts look just fine.

I might go deeper into the pump to see if I see any thing that looks incorrect. jdw
 
#14 ·
I've taken the pump apart and the three parts look OK. The pin is not broken, the moving part seems to work properly.

I changed the oil filter and replaced all the hydraulic fluid.

I started the motor and have a pressure gauge mounted to read the pressure created. However there is zero pressure when the motor is running and the pump is spinning.

Is there a "bleed" or "prime" process required when changing the oil to get air out of the system???

Anyone have any idea what I should do next? I sure would like someone to come to my house and look at this transmission. I would pay them for their time.

Thanks to all that have tried to help.

JDW
 

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