NMSH25 Low-Pressure Transmission Lubrication Gear Pump

NMSH25 transmission lubrication gear pump

NMSH25 is a low-pressure external gear oil pump used as a selection reference for tractor transmission lubrication systems. Its nominal displacement is 25 cm³/rev. This pump family has a compact oval housing and a mounting-face arrangement that differs from the NSH working-hydraulics pumps. Olive Branch Hydraulics is a Chinese manufacturer supporting configuration enquiries for Russian and CIS equipment.

The reference photographs show a red cast-iron-style sample marked НМШ25. They are supplier reference views for identification, not photographs of an independently verified Olive Branch production batch. Confirm the actual supplied material, model marking and installation drawing with the quotation. The visible НМШ25 marking must not be silently treated as НМШ25А.

Model names and search references

NMSH25, NMSH25A and aluminium-bodied B/В variants should not be merged as one confirmed installation. Suffixes can identify different shaft or construction arrangements. Shortened names help locate the family but do not establish mechanical interchangeability.

Low-pressure lubrication duty

NMSH transmission lubrication pumps belong to a different duty class from NSH implement-hydraulics pumps. Reference NMSH catalogues describe a 16 bar rated-pressure class, while an NSH specification may use much higher pressure. These figures must not be confused by a missing zero or a change between bar and MPa. The actual quoted pump requires its own approved operating limits.

Nominal displacement describes theoretical oil volume per shaft revolution. Actual flow depends on speed, pressure, oil viscosity and internal leakage. Lubrication performance also depends on the gearbox oil passages, inlet conditions and the condition of the associated circuit. Confirm the required operating speed and oil specification rather than selecting on appearance alone.

Installation details to check

Complete pump marking and any machine parts-book reference.

Drive shaft spline profile, diameter, projection and rotation.

Locating diameter, mounting-hole pattern and overall thickness.

Oil passage positions, sealing faces and gasket or O-ring arrangement.

Transmission model, operating oil, temperature, speed and pressure duty.

Photograph the original mounting face and shaft end, including any rotation arrow. Rotation should be described while looking at the drive-shaft end. A familiar oval outline or red paint colour cannot confirm the internal configuration. Approve the exact drawing before replacing or installing a pump.

Configuration review and order documents

Submit the full code, clear photographs and measured installation details.

Confirm model suffix, shaft, rotation, housing material and sealing interfaces.

Approve the proposed configuration drawing and inspection requirements.

Agree quantity, sample requirements, packaging and commercial terms.

Frequently asked questions

What is the nominal displacement of NMSH25?

The model family has a nominal displacement of 25 cm³/rev.

Is NMSH25 the same as NSH25M?

No. NMSH25 is a transmission lubrication pump reference with different construction and duty requirements.

Do the photographs identify an NMSH25A?

No. The visible sample marking is НМШ25. An A-suffix order requires separate configuration confirmation.

Does red paint prove the housing material?

No. Confirm material in the supply specification; paint colour alone is insufficient.

Can the catalogue pressure be used as a test certificate?

No. Catalogue values are selection references. Obtain the approved limits and any requested test documentation for the supplied pump.

How are price and delivery confirmed?

They are agreed in the quotation after configuration, quantity and documentation requirements are reviewed.

Request an NMSH25 quotation

Send Olive Branch Hydraulics the full marking, gearbox information, mounting-face photographs, shaft dimensions, operating requirements and quantity for configuration review and quotation.