Wa500-6 Komatsu transmission issue

[George catman]

Have just had a wa500-6 wheel loader arrive in shop with transmission full of hydraulic oil and and overheating transmission. Was wondering if any one had a workshop manual on the dash 6, looks like cab off Hydraulic pump out for a reseal?

 

[oldseabee]

A lot of trouble shooting to do first. Questions to ask.
1. Sudden problem or been coming on gradually?
2. Change in application example, moved from loading trucks to load and carry to feed a crusher?
3. New operator, could be a loose nut behind the wheel running in too high a gear?
4. Any slipping clutch?
5. Oil cooler clean, check pressure drop across cooler to see if it is getting plugged, check convertor out pressure to see if return circuit is plugged. Low convertor out pressure could indicate internal leakage in convertor, leakage oil doesn't get to cooler and generates extra heat.
6. Ambient temp change, right trans oil for the ambient temp?
7. Clutch pressure check for bypassing clutch piston or shaft seals.
8. Foaming oil, check for problem with suction hose to charge pump.

 

[John C.]

We don't see too many Komatsu loaders here anymore so I don't know much about your Dash 6.

The older models of those machines had the hydraulic pump on one side and the transmission pump on the other, with a switch pump mounted to the back of it. The switch pump was a gear pump and was prioritized to steering first and then excess flow to main hydraulics. The problem you describe was very common around the 5,000 hour mark on the older machines. Because the pumps had aluminum bodies we generally replaced the hydraulic pumps rather than try to reseal them. On the older machines we could get the pumps out without pulling the cab. It was not a pleasant job though.

I've heard the newer machines use piston pumps now but still have the aluminum body gear type switch pump piggy backed on the transmission pump. Let us know what you find.

 

[George catman]

Thanks for the advise, I'd really like to read up on a Komatsu manual to see what there action would be to remove the Hydraulic pump from talking to a couple of Komatsu guys it's definetly cab off pump out!

We don't see too many Komatsu loaders here anymore so I don't know much about your Dash 6.

The older models of those machines had the hydraulic pump on one side and the transmission pump on the other, with a switch pump mounted to the back of it. The switch pump was a gear pump and was prioritized to steering first and then excess flow to main hydraulics. The problem you describe was very common around the 5,000 hour mark on the older machines. Because the pumps had aluminum bodies we generally replaced the hydraulic pumps rather than try to reseal them. On the older machines we could get the pumps out without pulling the cab. It was not a pleasant job though.

I've heard the newer machines use piston pumps now but still have the aluminum body gear type switch pump piggy backed on the transmission pump. Let us know what you find.

 

[cps]

Thanks for the advise, I'd really like to read up on a Komatsu manual to see what there action would be to remove the Hydraulic pump from talking to a couple of Komatsu guys it's definetly cab off pump out!

Hi There George, Not got alot to do with the Komatsu loaders, but on the Volvos they have a hydraulic hand brake on the transmission that also can leak into it! Not sure about the set up on the Komatsus! Though i do have the manual for a wa500, if you send me an email il forward it to you!

Aiden

 

[George catman]

Hi Aiden,

I'm not sure on how to email you direct, but the workshop manual for the wa500-6 would be super helpful,
Thanks

 

[Steve 650]

On wa 500 later model there was 4 hydraulic pump drive by the torque housing transmission. one upper left, one upper right, one under left, one under right. Its a pain in the a#s remove those b#st#rd pumps. the only way to know what pump is shut is to know what device is not working right and follow the hose routine with the manual.

 

[Barbarobarbarit]

Wa500_3

Hi There George, Not got alot to do with the Komatsu loaders, but on the Volvos they have a hydraulic hand brake on the transmission that also can leak into it! Not sure about the set up on the Komatsus! Though i do have the manual for a wa500, if you send me an email il forward it to you!

Aiden

I have the same problem.
I need to follow the hose route on the diagram.
Can you help me with the manual..?
Julioedgar@gmail.com

 

[Lewis12]

What ended up being the problem with th3 hyrdaulic oil getting inside the transmission?

 

[George catman]

Hello,

The main implement pump (variable displacement piston pump) had failed. Thus leaking oil into the trans, we removed all 6 pumps from memory from the machine stripped and resealed 5 other pumps and replaced the piston pump with an genuine unit. Out the door she went. Upon re assembly we also found main return line from hyd cooler to tank had a severe kink into the tank. Not sure if it contributed to the failure but certainly wouldn’t of helped slowing down cooler oil.

Cheers