Where do I find the level for Hydraulic fluid on CASEIH MAXXUM 5140

Error code -51 on a Clark forklift typically indicates a problem with the hydraulic system. This could be caused by a variety of issues, such as a faulty hydraulic pump, a leak in the hydraulic system, or a problem with one of the hydraulic valves.
To troubleshoot this issue, you will need to first check the hydraulic fluid level and make sure it is at the correct level. If the fluid level is low, refill it to the proper level and see if the error code clears.
If the fluid level is fine, you may need to perform further diagnostic tests to identify the root cause of the problem. This could involve checking the hydraulic pump and valves for any visible signs of damage or malfunction, as well as testing the system for leaks.
If you are not comfortable performing these tasks, it may be best to contact a professional mechanic or the manufacturer for assistance. They will be able to diagnose the problem and recommend the appropriate repairs.

Question edited for clarity.
Question moved to a Thor motor Coach challenger category.

Mentioned in the forum. In my experience, it is shown in tiny embossed letters on the filler cap.

Owners Manuals ' Thor Motor Coach

https://www.thormotorcoach.com > owners > owners-m...
For detailed information on your Thor Motor Coach motorhome, please locate your owner's manual from the list below.
Missing: suspension ‎' Must include: suspension

Level up hydraulic fluid? - Thor Forums

https://www.thorforums.com > forums > level-up-hydra...
Jan 8, 2020 - Does anyone know where is the Hydrolic Resiervior is located on a Thor Class C Quantum PD 31 to add fluid to Leveling Jacks?
Missing: 37gt ‎' Must include: 37gt

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  Hydraulic Fluid for leveling jacks - Thor Forums

  https://www.thorforums.com > forums > hydraulic-fluid...
  We have a 29.3 Thor Ace 2015. What should I use for Hydraulic Fluid in this system? Thanks. If you have a Lippert leveling system Type A Automatic Transmission ...

Check hydraulic/transmission fluid level.

If fluid level is good then likely a steering pump i$$ue.

Fluid level? last time fluid and filter changed? Color of fluid? I'd guess the hydraulic pump is not getting enough fluid due to level or blockage. Possibly a crimped hydraulic line. Could also be a Bad wheel bearing or gears or lose Hydraulic motor so gear is not in proper position.
You "may" be able to find manual here: https://www.manualslib.com/
Or: http://www.manualsonline.com/

It can be both hydraulic and electric problem I recommend a specialist it needs a skilled person it is not DIY matter

As a rule the Kubota L2800/L3400 do not have a dip stick for the hydraulic fluid. To check the fluid level, find the small round site glass that is on the transmission, left side, just in front of the clutch pedal. This sight glass has a level line on it. If the level is low the fluid might not show in the sight glass. If the level is below the line add fluid. The fill port for the Hydraulic fluid is on the back of the tractor just below the level of the seat.

This Brake fluid level is a reservior of brake fluid near the hydraulic master cyclinder it will indicate the level it should be at on the side of the reservior or on the dip stick attached to the cap of the reservior. if it keeps running out after you top it up with hydraulic brake fluid you have a leak in your braking system and need to get your brake system checked out.before you find out you can't stop the car.!!

caseih hytran fluid is used for hydraulics and transmission fill through plate on top of deck next to shifter check plug is located on left side of transmission housing next to clutch linkage rod probably square headed pipe plug

Check your power steering fluid level. The power brakes are hydraulic assist and get hydraulic pressure from the power steering pump. If the fluid level is good you may have a bad pump. If the fluid level is low fill it up and find the leak .