No Hydraulic fluid level but overfull transmission oil?

[justsomedude]

Hi there

I've recently brought my machine (2010 cat420EiT) back from a site it was being used on and while going through it i ran into something i don't understand.

when looking at the hydraulic oil sight glass to see the level it shows nothing. not even below minimum. just looks totally empty yet all functions are working. So i went and bought and poured in a 5 gal bucket into the filler tube with the blue plug in it. Still the sight glass shows no level at all. No puddle of oil under the machine after pouring the entire bucket in. Hydraulics seem to operate but haven't tested them with a load. Machine will drive forward and backwards seemingly with no issues but I've only moved it a short distance.

When i check the transmission oil the dipstick seems to show it as very over full and the fluid is clean and clear like the hydraulic oil i just poured into the hydraulic tank.

Question 1: Is there a condition by which hydraulic oil can escape the hydraulic tank and get into the transmission somehow while not even running? 5gal of oil is a lot of fluid to escape instantly.
Question 2: Is this machine ok to drive (im assuming its not)
Question 3: is this machine ok to use the hydraulics (im assuming not)
Question 4: if the answer to question 1 is yes is that an expensive fix?

I'd appreciate any insight anyone could share with me.

 

[92U 3406]

Hydraulic pump is probably driven off the transmission.

 

[Nige]

Where are you filling the hydraulic system.? The filler cap marked with the arrow.?

EDIT: Sorry, forgot the diagram.

 

[justsomedude]

Hydraulic pump is probably driven off the transmission.

Where are you filling the hydraulic system.? The filler cap makred with the arrow.?

Hi Nige.
From what i understand the fill cap is in the engine compartment with a blue cap / plug for hydraulic and a purple one with a dip stick for transmission and a yellow one further away for engine oil and an associated dip stick. I poured the 5 gallon bucket into the tube that had the blue plug in it that sits just forward of the windshield washer reservoir. On the plug there is an icon that looks like a cylinder with a liquid drop in it. Is there more to this process like running the machine or actuating the hydraulics a bunch to get it to register in the tank?

 

[justsomedude]

Hydraulic pump is probably driven off the transmission.

does this indicate some kind of seal between these components has failed?

 

[Nige]

Hi Nige.
From what i understand the fill cap is in the engine compartment with a blue cap / plug for hydraulic and a purple one with a dip stick for transmission........

That's correct. It was somewhat of a trick question to get to the bottom of whether you were adding the hydraulic oil to the correct system - you are.

Hydraulic pump is probably driven off the transmission.

It is, so a failed pump input shaft seal would be the #1 suspect for hydraulic oil finding its way into the transmission. However a failed seal might be the indicator of something more serious inside the pump. It's a piston pump and pretty complex inside. I wonder how much flow there is in the pump case drain line.?

What's the machine Serial Number and how many total hours are on it.?

 

[justsomedude]

Where are you filling the hydraulic system.? The filler cap marked with the arrow.?

EDIT: Sorry, forgot the diagram.

View attachment 273421

nope. the other one above it. the one indicated in the diagram had a purple plug with a dipstick and a gear icon on it. Are you dead certain that's the correct tube? Maybe one the the brilliant minds i work with swapped the plugs??

 

[Nige]

nope. the other one above it. the one indicated in the diagram had a purple plug with a dipstick and a gear icon on it. Are you dead certain that's the correct tube? Maybe one the the brilliant minds i work with swapped the plugs??

I am certain, it was a trick question to get you to identify the hydraulic filler. The arrow in the illustration points to the purple transmission fill tube with the dipstick. I just wanted to make sure you were filling oil into the correct hole.

This is the hydraulic tank filler.

 

[justsomedude]

That's correct. It was somewhat of a trick question to get to the bottom of whether you were adding the hydraulic oil to the correct system - you are.
It is, so a failed pump input shaft seal would be the #1 suspect for hydraulic oil finding its way into the transmission. However a failed seal might be the indicator of something more serious inside the pump. It's a piston pump and pretty complex inside. I wonder how much flow there is in the pump case drain line.?

What's the machine Serial Number and how many total hours are on it.?

Machine serial DAN00662 about 6300hrs on it.

Hopefully whatever is wrong here is inexpensive to fix. Just got done having the engine and platform wiring harnesses replaced for 20k. Cant really afford another big repair bill.

 

[justsomedude]

Is it worth removing the pump and bringing it to a hydraulic shop to have them look at rebuilding? Kind of hoping its just the shaft seal is worn from age and the pump isn't full of shrapnel (fingers crossed).

I have pretty limited mechanical experience. Hopefully this is something i can remove myself. Anyone know of any important steps pitfalls or tips before i try and dig in to this. I'm guessing once that pump is off its impossible to move the machine. I'm also assuming the moment i crack the bolts the hydraulic tank is going to want to dump out unless i drain it before. how about the transmission would that begin to leak once i remove this part?

 

[Nige]

Here's the procedure to remove the pump.
If you do take it to a shop and they want the disassembly & assembly instructions just ask.

 

[justsomedude]

Here's the procedure to remove the pump.
If you do take it to a shop and they want the disassembly & assembly instructions just ask.

you sir are amazing. Thank you for your help.