John Deere 648E Grapple Skidder Transmission Overfilling

[Simon C]

John Deere 648E Grapple Skidder
Ser# DWG648E
H536108

We Believe this is the correct Serial Number as it was Partially Damaged. Don't have a service manual and am trying to find out if this machine has more than 1 Hydraulic Pump running off of the transmission, as the transmission is over filling quickly all of a sudden . Going to the bush to look at it in the morning and trying to get informed before. Anyone who knows of the pump or pumps running off the transmission, Your help would be appreciated. Picture would be best or PDF. Thanks in Advance For Your Help. Simon

 

[mg2361]

DWG648EH536108

Serial number does not come up in the system, so it is incorrect.

I'm probably a little late here and you have already been to the machine. There is the main hydraulic pump and the diff lock/park brake pump mounted to the transmission. Only the hydraulic pump of the 2 can transfer fluid.

Another area that can overfill the trans besides the hyd pump seal is the brake seals. If the axle overfills from the brakes the oil gets pushed back to the transmission via the turbo return system. For your information that turbo return system is for the diff lock circuit. The diff lock is not sealed from leakage so it can leak into the axle. The activation of that system is from transmission pressure oil. So the turbo's return system pushes that oil back to the trans. There is a line from the engine's intake manifold connected to the axle, allowing boost pressure to pressurize the axle, which pushes the oil back. The brakes are engaged with the hydraulic system. So if the brake seals leak, the hyd oil level goes down and the trans goes up through that system.

 

[Simon C]

Serial number does not come up in the system, so it is incorrect.

I'm probably a little late here and you have already been to the machine. There is the main hydraulic pump and the diff lock/park brake pump mounted to the transmission. Only the hydraulic pump of the 2 can transfer fluid.

Another area that can overfill the trans besides the hyd pump seal is the brake seals. If the axle overfills from the brakes the oil gets pushed back to the transmission via the turbo return system. For your information that turbo return system is for the diff lock circuit. The diff lock is not sealed from leakage so it can leak into the axle. The activation of that system is from transmission pressure oil. So the turbo's return system pushes that oil back to the trans. There is a line from the engine's intake manifold connected to the axle, allowing boost pressure to pressurize the axle, which pushes the oil back. The brakes are engaged with the hydraulic system. So if the brake seals leak, the hyd oil level goes down and the trans goes up through that system.

Thanks mg2361. So I went to the machine and Serial # is a T Instead of the H as I see it with a magnifier. Here is what I found. It was minus 15 Celcius and the transmission had 8 inches too much in it. Hydraulic tank was down the equivalent.Emptied the transmission and put back in the proper oil. Filled the Hydraulic tank to the proper level. Found the fan belt totally loose to the point that the fan would spin if you gave it a tug. Rad was very dirty so blew it clean for 1 hour. Tightened up belt and with boost started motor only to find that it would not put out any amps. Touched with a jumper wire from Alternator output terminal to the small terminal above it for 1/2 a second and instantly charging again. 60 amps for first minute and going down slowly to 30 amps. Maybe it lost its magnetism.
Now for the oil leak. We put lots of Dye in the hydraulic oil and took it for a good drive to see if it would transfer to the transmiission. One hose with a tiny leak would show the Dye very clearly on a white Kleenex. But not any oil left the hydraulic tank to find its way into the Transmision. No dye colour at all in the transmission . The day before when this happened the temperature outside was about plus 8 Celciius. Maybe the Hydraulic oil and transmission oil got very hot with the fan not cooling and the the pump was bypassing. Maybe it was a slow leak over 1 week that overfilled the transmiision. If we pulled the pump off when it does it again we may find the dye leaking out by the pump shaft. How would you know if it was the front or rear brake seals, or could the small differential lock pump leak out the seal into the back end of the transmiision charge pump and enter the transmission there also. Will have to see what it does in the cold Minus 17 Celcius today. Any of your input would be much appreciated . This is all the info that I have for now and will let you know what I find out later. Thanks Simon

 

[mg2361]

Here is the proper serial number (DW648ET536108) for your records. Unfortunately the serial number is not telling me if this unit has just a front diff lock or front and rear diff lock. Skidders typically have a diff lock on both axles. Following the turbo line from the intake would answer that question because there would be a tee with a hose running to each axle.

If we pulled the pump off when it does it again we may find the dye leaking out by the pump shaft. How would you know if it was the front or rear brake seals, or could the small differential lock pump leak out the seal into the back end of the transmiision charge pump and enter the transmission there also.

The diff lock pump is moving transmission oil so if the shaft seal leaked it wouldn't matter, so ignore that. If the brake seals are leaking, they could be a painfully slow leak that may not show up for months. Hydraulic pump seal would transfer at a quicker rate, but again could take some time. My suggestion is since the oils are at the correct levels is to let the customer run it (hard hopefully) for a week or two, maybe longer, and keep a daily check of the fluid levels. When the level change is obvious then check for the dye.

If it is determined that the leak is from the brake seals I would suggest doing all 4 brake seals.

 

[Simon C]

Here is the proper serial number (DW648ET536108) for your records. Unfortunately the serial number is not telling me if this unit has just a front diff lock or front and rear diff lock. Skidders typically have a diff lock on both axles. Following the turbo line from the intake would answer that question because there would be a tee with a hose running to each axle.



The diff lock pump is moving transmission oil so if the shaft seal leaked it wouldn't matter, so ignore that. If the brake seals are leaking, they could be a painfully slow leak that may not show up for months. Hydraulic pump seal would transfer at a quicker rate, but again could take some time. My suggestion is since the oils are at the correct levels is to let the customer run it (hard hopefully) for a week or two, maybe longer, and keep a daily check of the fluid levels. When the level change is obvious then check for the dye.

If it is determined that the leak is from the brake seals I would suggest doing all 4 brake seals.

Thanks for your reply. Now I know where the Diff. lock pump gets its oil from, so no chance of there being bypass to the transmission from that pump. Probably slowly from the brake seals which will turn up eventually or from the pump. Cold weather all this week so machine will be working every day.
Thanks again. Will keep you posted when it refills again.

 

[Simon C]

Thanks for your reply. Now I know where the Diff. lock pump gets its oil from, so no chance of there being bypass to the transmission from that pump. Probably slowly from the brake seals which will turn up eventually or from the pump. Cold weather all this week so machine will be working every day.
Thanks again. Will keep you posted when it refills again.

Rear differential housing oil is all Blue and none in front differential housing yet or not blue enough to see. Rear diff will be coming out to reseal brake pistons. I did not have time to check the manual but do you know if those are SAHR Brakes (spring applied hydraulically released) or are they pressurized to apply brakes. Hydraulically released ones will eventually drag as they bypass more and more oil. Transmission was up 6 inches but the oil is diluted by the time it comes from rear diff. Added more blue dye today. Should know bettter by few days from now. Simon

 

[Simon C]

Rear differential housing oil is all Blue and none in front differential housing yet or not blue enough to see. Rear diff will be coming out to reseal brake pistons. I did not have time to check the manual but do you know if those are SAHR Brakes (spring applied hydraulically released) or are they pressurized to apply brakes. Hydraulically released ones will eventually drag as they bypass more and more oil. Transmission was up 6 inches but the oil is diluted by the time it comes from rear diff. Added more blue dye today. Should know bettter by few days from now. Simon

Looking for CTM-43 For disassembly of the rear diferential. Machine Ser# DWG648ET536108 If you know someone who has this section of repair we would greatly appreciate. We already have Repair, Testing a nd Adjusting, and parts. Thanks Simon

 

[mg2361]

Actually I believe the rear axle on that machine is a 1200 series axle (axle serial number beginning with ROAG250 - 1200 series, ROAG251 - 1400 series) which requires CTM138519. I think the front axle on that machine is a 1400 series axle. 1400 series axle manual is CTM138619.

 

[Simon C]

Actually I believe the rear axle on that machine is a 1200 series axle (axle serial number beginning with ROAG250 - 1200 series, ROAG251 - 1400 series) which requires CTM138519. I think the front axle on that machine is a 1400 series axle. 1400 series axle manual is CTM138619.

Thanks for that Info.

 

[Simon C]

Thanks for that Info.

This skidder is still running every day till job is done. They drain 3-4 liters from transmission every 5 hours, coming from rear diff. piston seal leaking. There will be a diff. rebuild happening in the spring.Thanks for your help mg2361. The machine is on totally flat ground so the brakes get used rarely so less leakage. Simon

 

[Simon C]

Thank you mg2361. The rear differential was taken apart by the owner and yes both piston seals for the rear brakes were gone. Thats why it was dumping blue dyed hydraulic oil into the rear diff. and draining back to overfill transmission sump.
Many thanks again. Just wanted you to know that you were 100 Percent correct. Simon C in Rocky Mountain House Alberta