6410 Hydraulic temp light coming on

   / 6410 Hydraulic temp light coming on #1  


Jul 1, 2014
PineBush, NY
John Deere 6410
I'm having an issue with my 6410 that perhaps someone could help with?

I recently had to change the pump located inside the front of the transmission. I noticed the shaft was cracked (on the outside, no damage inside) while changing out the u-joints on the short driveshaft from the engine. I think the prior owner had a joint fail, and when the shaft was spinning wildly perhaps it chipped the shaft end? Everything came apart and went together easily as it should, I refilled the system, changed all filters and fired it up. After about 30 mins of loader use my hydraulic temp light comes on, and I'm not sure if its psychological or not, but it seems like the pump in the rear is making a bit more noise than usual from the start I shut the machine down to let things cool (the filter on the right rear side does feel hotter than normal), I check the fluid and find small bubbles in it. I topped off the system to make sure I was good, and everything repeated.....30mins of use, light comes on....shut down. Did I miss a step during reassembly where I should've bled or primed the system somehow? Everything works as it should, steering, breaking, loader and all gears and ranges of the transmission; however, I do feel a little shutter when I'm in a higher range gear. I replaced the temp sensor already, thinking it may be a culprit; and both boom cylinders are currently getting rebuilt because I did have some seal leaking issues, they always leaked just a tiny bit, but I think the hotter fluid caused them to fail all together (just the seals on the shaft end, the piston end worked fine to raise and lower). One other note...the hose that is clamped off the bottom of the reservoir in the rear behind the SCV's appears to have moved a bit, maybe 1/2"?? As if the pressure was increased to the point where it was being pushed off the nipple. I only noticed this because an area where there was no green paint caught my eye... may not even be related, but thought I'd throw in in there too.

Any ideas??
   / 6410 Hydraulic temp light coming on #2  
:welcome: to TBN

You sure have a lot of "indicators" that something is amiss.
I've no good ideas for you, but others' with more experience will likely be along to help give you some guidance, or places to check.
   / 6410 Hydraulic temp light coming on #3  
In the transmission pump is an air pump that pressurizes the front of the housing to push oil to the rear of the housing. This keeps the oil level in the front down to an acceptable level so the gears aren't churning in the oil causing excess drag and heat. It sounds like that air pump may not be working properly. The hard plastic line on the top of the transmission is the suction line for that pump. If you pull that hose off and put a vacuum gauge on the front port, you should see a minimum of 10 inches vacuum at 2000 rpm. If less than that, pull the front back off the transmission and check that air pump. It is basically a piston that runs off of the eccentric cam on the driveshaft. There is a spring and check balls in there also. sEE ITEMS IN BOX ITEM #6.


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   / 6410 Hydraulic temp light coming on
  • Thread Starter
Decided to revisit this issue, as we now need to use the tractor for hay. Still having issues with overheating after about 45 mins of use, which isn't going to work for us. The pump whines as soon as it's started, still have a shudder when moving. I reviewed several posts online, it appears a check valve on the braking system typically has an o-ring failure. Checked that and found it was broken completely, replace it and still have the issue. Checked the priority valve spool and it's moving freely, also checked the compensation valve. Both are also working smoothly. I had a leaky hose that ran from the pump to the priority valve and another one from the reservoir on top of the pump, both hoses were replaced. All filters and fluid has been changed. When i used the loader the tractor wants to stall out, steering and brakes both work fine, but definitely changes the sound of the pump when used. I checked all scv outlets and get a pressure reading of 2800 when used. Not sure where else to look, thinking the pump is on it's way out? Maybe the check valve problemin the brake system started this mess?
   / 6410 Hydraulic temp light coming on
  • Thread Starter
I checked the vacuum on the hose as jd110 suggested and got a reading of 20 inches.
   / 6410 Hydraulic temp light coming on #6  
Reading back through your original post, You mentioned air bubbles in the oil. Has the sump screen been checked? Also could be leak at suction port on charge pump under the rear main hydraulic pump.
   / 6410 Hydraulic temp light coming on
  • Thread Starter
I pulled the main pump and charge pump. Replaced several hoses that were beginning to show their age (including all 3 large hoses that connect to the charge pump), replaced the gasket and plastic disk where the main pump mounts to the charge pump. While replacing hoses i found that the bleeder valve was completely packed shut with mud and debris, cleared it out and replaced it. I opened up the main pump, found a little wear on the bearing races and rollers, but not sure if it's enough to cause it to not work properly. Where is the screen located? Is it possible the slight wear i found in the pump could cause poor performance and overheating?
   / 6410 Hydraulic temp light coming on #8  
I would almost have to see the pump myself to determine if wear would cause a problem. A hydraulic pump has very close tolerances and it doesn't take much wear to cause problems. Can you post any pictures? The screen is located in the differential housing on the left side standing behind the tractor. near the bottom of the left axle housing you will find a plug that takes a 7/8" socket. I recommend a 6 point socket since plug is plastic and easily rounds off with 12 point. check parts 7, 11, 12 in diagram.


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   / 6410 Hydraulic temp light coming on
  • Thread Starter
The bearing is from the top of the pump shaft. I haven't ventured further down to the lower bearing yet.


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   / 6410 Hydraulic temp light coming on #10  
The bearings are showing enough wear, but the pistons and cylinder block appear pretty good. I don't think the pump is the source of your problem.