2018 Toolcat 5600, 2100hours, barely moving forward or backup after a hose break repair

[RichardV-Quebec]

In January (-20C) pushing snow, one of the front right behind the wheel hose broke on the 90 degree iron coupling. All the hydraulic oil ended on the snow. The 5600 stayed there for about one month. I put a screw on hose coupler and changed the other end. Put oil back in and was able to use the machine for about 1 hours then it started to loose moving power either going forward or backward. The front lift and bed hydraulic work fine. It is only the moving part that is the problem. There is a kind of slipping sound coming from the front of the machine. I can get by this (for a short while) by increasing the throttle and it will move more firmly but as it gets warmer, it will loose driving power again even at higher RPM. I changed the hydraulic oil and both filters, opened the filters and there are no debris in them. No luck, same problem. Someone suggested the belt may be loose. I opened the belt cover and the belt is tight and tensionner blocker is very close. There are no warning lights suggesting an error code. Trying to understand this problem, I depress the gas pedal slowing, TC starts moving and when I let go the gas pedal, TC slowly stops as opposed to before (when it was working fine) it would stop immediately. I wonder if this could be a stucked relief valve ? and if so, where would it be? Any ideas anyone ? Thank you.

 

[Interceptor]

The drive system relief valves are in the pump. There is one for forward and one for reverse, so if you are having problems in both directions it's not likely a main relief valve problem unless somehow they both failed at the same time. There is a loop flushing valve in the motor, it allows a small amount of oil to bypass the motor and exit the drive loop to be cooled. This is a spool that shifts when changing direction, so again it's not likely to be the problem. There is a flushing relief valve in the motor, if stuck open it could cause excessive bypass in both directions and could also cause excessive roll out when releasing the pedal. But the orifice in this valve is very small, I wouldn't think it could possibly flow enough to be causing the type of problem you describe.

 

[Xfaxman]

Put oil back in and was able to use the machine for about 1 hours then it started to loose moving power either going forward or backward.

What type of hydraulic oil did you put in it?

 

[RichardV-Quebec]

HD46 Mobil is the oil I just changed with. I am going to make a video of the problem and put it on Youtube for you all to watch. I was expecting metal in the filters when I opened them up but there are no debris of some sort and no milky oil also. Maybe air is in the system but someone said it is a self bleeding system ! unless there is a problem with that process. After the oil change, the ball in the SG is high but the oil level show low ? wonder if the ball is stucked in the high portion ?

 

[RichardV-Quebec]

The drive system relief valves are in the pump. There is one for forward and one for reverse, so if you are having problems in both directions it's not likely a main relief valve problem unless somehow they both failed at the same time. There is a loop flushing valve in the motor, it allows a small amount of oil to bypass the motor and exit the drive loop to be cooled. This is a spool that shifts when changing direction, so again it's not likely to be the problem. There is a flushing relief valve in the motor, if stuck open it could cause excessive bypass in both directions and could also cause excessive roll out when releasing the pedal. But the orifice in this valve is very small, I wouldn't think it could possibly flow enough to be causing the type of problem you describe.

Could it be the shaft moving the swash plate is not working correctly ?

 

[ruffdog]

HD46 Mobil is the oil I just changed with. I am going to make a video of the problem and put it on Youtube for you all to watch. I was expecting metal in the filters when I opened them up but there are no debris of some sort and no milky oil also. Maybe air is in the system but someone said it is a self bleeding system ! unless there is a problem with that process. After the oil change, the ball in the SG is high but the oil level show low ? wonder if the ball is stucked in the high portion ?

It sure looks like the level is low (who knows by how much) and the ball is just stuck to the top. I went out to look at mine with a good light and mirror. Before running it too much, I would want to see the fluid half way up the glass!

 

[Interceptor]

Could it be the shaft moving the swash plate is not working correctly ?

The pump swashplate angle is controlled by a servo which is controlled electronically by the drive controller. There's a swashplate angle sensor, so the controller would know if it's not moving properly in response to input and set a code. There is only one drive pump on the 2007 and newer TC, so a pump problem would affect both front and rear drives equally. The motor swashplates only move when you shift between high and low speed. If you are getting an unusual noise from the front it makes sense that there's an issue with the front drive. I would get all four wheels off the ground and see what's happening with front and rear wheel speeds. The pump flows oil to both motors in parallel, so there can be some variation in wheel speed between front and rear, but with no load they should be very close to the same.

It could also be the brake pressure bleeding off and causing the brakes to apply. This doesn't fit with your description of excessive rollout, but something to consider. The brakes are spring applied, hydraulic release. Check the brake hose for external leaks. Also check gearbox oil level, overfilled gearbox would indicate an internal brake piston leak.

 

[RichardV-Quebec]

The guy who sold me the TC was using AW-32(1st picture) from NAPA and that is what we put in after the hose was temporarely fixed. Last year, we had a leaking bed hose and we added AW-32 also. After the repair(3rd picture), the hose union leaked and I had no more of that oil so I put the trans-30 Oil (see 2nd picture). The 3rd picture shows the repair hose and union. I thought I used HD46 but I was wrong ! Maybe HW30 (2nd picture) is too weak ? The seller gave me a service manual but not for that serial number (mine is AHG815055) so instructions in the manual for gear box oil checking does not match my machine. I ordered the correct manual today and I should get it in 1 week(lol). Could it be the oil is the problem ? I tried filming today the weird sound it makes, trying to move forward. Backward seems to work somehow a bit more but has the same weird sound. Thanks for all the explications so far. It is my understanding the broke hose feeds the front coupler for the lift arm etc...but I could be wrong.

 

[RichardV-Quebec]

Today, for the 1st time, I tried the recording cam, here's the youtube link.

 

[Xfaxman]

Could it be the oil is the problem ?

Yes, that is why I asked what type you put in it.

Many years ago I had a Case 446 garden tractor that acted similar if you used hydraulic oil instead of the motor oil it was designed for.

 

[Interceptor]

I would be very surprised if the oil is the problem. It's not ideal to run the wrong type long term, but it won't cause the issue you're having. The sound in your video is not good enough to be helpful, but it looks like maybe the brake is not releasing.
That is a front drive motor hose that you repaired. Are you sure the field repair fitting is installed properly? I have seen where they cut into the inside of the hose when screwed in and create a flap of rubber that blocks the hose. It's not likely, but I've seen it happen and completely block flow.
I would get all four wheels off the ground and see what's happening. Does the TC have traction control?

 

[RichardV-Quebec]

Yes, that is why I asked what type you put in it.

Many years ago I had a Case 446 garden tractor that acted similar if you used hydraulic oil instead of the motor oil it was designed for.

I will change the oil today and let you know.

 

[RichardV-Quebec]

I would be very surprised if the oil is the problem. It's not ideal to run the wrong type long term, but it won't cause the issue you're having. The sound in your video is not good enough to be helpful, but it looks like maybe the brake is not releasing.
That is a front drive motor hose that you repaired. Are you sure the field repair fitting is installed properly? I have seen where they cut into the inside of the hose when screwed in and create a flap of rubber that blocks the hose. It's not likely, but I've seen it happen and completely block flow.
I would get all four wheels off the ground and see what's happening. Does the TC have traction control?

I thought that hose was going to the front equipment. I wanted to change the whole hose but couldn't figure out where the other end was going to without removing the cab. I know the guy who put the fitting had a hard time screwing it in the hose. I certainly will undo it and check that out. Not sure but I think the TC does have traction control by default ?

 

[Interceptor]

If I'm seeing it right, it's a drive motor hose. They attach to long straight fittings that extend out through the side of the frame. The other end goes to the piston pump in the center of the machine. I'm guessing something got into the hose when it was open and has now made it's way into the drive loop where it's causing problems. The hydrostatic drive system is closed circuit, most of the oil stays within the loop flowing round and round, only a small amount of oil is released and replenished for cooling. If a large piece of debris gets in there it will likely stay in there until you disassemble and remove it.
Traction control is optional. If your TC has it there will be a switch on the dash to turn it off. I have no personal experience with it but have read that a bad speed sensor can cause the traction control to do weird things.

 

[RichardV-Quebec]

If I'm seeing it right, it's a drive motor hose. They attach to long straight fittings that extend out through the side of the frame. The other end goes to the piston pump in the center of the machine. I'm guessing something got into the hose when it was open and has now made it's way into the drive loop where it's causing problems. The hydrostatic drive system is closed circuit, most of the oil stays within the loop flowing round and round, only a small amount of oil is released and replenished for cooling. If a large piece of debris gets in there it will likely stay in there until you disassemble and remove it.
Traction control is optional. If your TC has it there will be a switch on the dash to turn it off. I have no personal experience with it but have read that a bad speed sensor can cause the traction control to do weird things.

First, thank you very much for your feedback ! Yesterday, when I ordered the correct service manual for the AHG8 series, the dealer told me the parts catalog is online. I went and looked at the hydraulic section and YES, the two hoses go right into the front drive motor. I removed the front plate below the front attachment and confirmed. Had I known this when it broke, I would have been a LOT more carefull. (I had a bad experience with a D31PX-21 hydrostatic transmission where the swash plate cage bearing broke). It looks like I can access the other end of the hoses by removing the driver seat, the air filter cage and the hydraulic reservoir. Next step is to inspect the coupler fitting repair. I will let you know. Also, it turns out I have that switch.

 

[RichardV-Quebec]

Well, I decided to change the whole hose. I think the union fitting and the 90 degree fitting on the drive motor is causing restriction as opposed to the other hose below. Also I noticed one the rear motor pump is leaking a little bit on the hydraulic pump side, so ... I will change all 4 hoses and let you all know the results. What is the front below hose used for ? or how does this work ? Is flow always in one direction and a pilot line reverses the swash plate ? I saw there is one line to switch in high speed. How does reverse work ? I understand the brakes are inside the gear box according to the manual I have (which is not for my TC). Thanks to all for all the help.

 

[Interceptor]

The swashplate in the pump reverses flow to the motors. When traveling forward one hose is pressurized, and when traveling reverse the other hose is pressurized. The swashplate in the motors does not change direction, it only changes angle to switch between high and low speeds. So besides those two big drive loop hoses, there is a smaller third hose going to each motor to pressurize the two speed servo, and a fourth hose for case drain which bleeds off hot oil to be filtered and cooled.

 

[RichardV-Quebec]

Update. I did not change the front motor hose yet. As you suggested, I removed the oil check plug from the front axle. I did get a small blow out of oil when I removed it and a bit of overflow afterwards. I am wondering if the brake hose is leaking inside the front axle, will it spill oil out of the check plug when I run it forward or reverse? I also noticed the right cv bar is oily on the outside, maybe that is from the oil spill of the hose when it busted.

 

[RichardV-Quebec]

Update. I replaced the hd oil today with HD 56 and no change on the problem. I can move the TC out of the garage but 2 mins after it will barely move forward or backward unless I increase the throttle. Eventually full throttle will not work either as it gets warmer. Today's outside temperature was 31C or 88F. The first time I removed the HD oil from the tank to replace it with HD56, the oil looked normal. But then, with the HD56, we cycled the front attachment (we had emptied the charge filter and return filter). I supposed that forced new oil to be purged from whereever, and the oil in the tank got milky! So we emptied and added oil 3 more time until the oil did not look milky. Yet still the same problem. Next, I will change the front motor hoses hoping it is a restriction issue !? I just wanted to make sure OIL was not the problem.

 

[RichardV-Quebec]

I guess I should test the charge pump pressure at this time ! The front attachment and back bed is working fine and is very responsive.