TRANSMISSION - How to get maximum life - Dos and Donts

Because of the wide variety of work they do, Various Earth moving machines use several types of transmissions, including planetary powershift, countershaft powershift, direct drive, and hydrostatic. Each is designed to convert engine power into the exact combination of speed, direction, and torque required for the particular application.

Transmissions do this by various means such as hydraulic clutches or a hydrostatic/hydraulic drive. Transmissions rely on the engagement of gear groups to provide the transfer of power to your machine components. Manufacturer designs all parts, including these gear groups, to fall within three wear categories. Understanding which parts wear faster will allow you to inspect for signs of wear and keep your transmission running smoother and longer.

For example, gears and shafts, if properly maintained, are designed to last through multiple transmission rebuilds. But components such as friction material, seals, gaskets and bearings are faster wearing. Monitor them for abnormal wear and replace when needed. To increase productivity and prevent downtime, it’s vital to make sure that all drive train components are constantly monitored.

Look at their condition to ensure contamination isn’t entering their systems and to check that correct operating techniques are being used. This article focuses on how to identify problem indicators and how to maximize the performance and life of your transmission.

IMPORTANCE OF S.O.S ANALYSIS

Many years ago it became apparent that the oil used to achieve maximum engine life would not perform satisfactorily in transmissions. Consequently, Equipment manufactrers developed specifications for transmission oil just as the Company has done with engine oil for many decades. Equipment manufacturers developed transmission oil specifications to maximize the performance and life of their products. Since only Manufactrer engineers know exactly what metallurgical specifications were designed into each part and component, they were also able to develop an oil analysis program to help accomplish these goals. When selecting lab instruments and tests for S?O?S fluid analysis, Equipment manufacturer engineers begin by asking what information from used oil samples would best identify the transmission’s condition. Surveys show major benefits for users who regularly use S?O?S fluid analysis.

A 10:1 payback is common when comparing the amount saved on repair costs to the amount invested in S?O?S fluid analysis. This figure is probably conservative when you consider reduced downtime, greater productivity and increased used-machine value.

S?O?S fluid analysis testing is quick and easy to do. Sample test analysis is done in your dealer laboratories by trained technicians using the most modern technology. These experts know what’s happening inside the transmission and how it relates to sample findings. They draw on a large database of information and wear tables developed through years of testing and evaluations.

The following wear table outlines transmission failures and their common indicators using the S?O?S fluid analysis.

Friction Material

? Si, Cu, Pb (friction materials)

? Fe (separator plates)

? ISO Code (larger particles)

? Oxidations (caused by overheating the oil)

? Incorrect fluid (difficult to identify)

Sticking Control Valves

? ISO Code (larger particles)

? Fe (debris)

? Oxidation (caused by overheating the oil)

Bearing or Bushing Failure

? Cu, Pb and/or Sn (bronze bushing or thrust washer)

? Cr (rolling element bearing)

? Fe (rolling element bearing, shaft, iron housing)

? ISO Code (larger particles)

Dirt Entry

? Si & Al (dirt)

? Fe (separator plates, gears)

? Cu, Pb, Sn (bronze bushings or thrust w

IMPORTANCE OF S.O.S. FLUID ANALYSIS

INDICATORS

If excessive amounts of silicate (Si) and aluminum (Al) are found in the transmission fluid, it means the oil is contaminated with dirt. The S?O?S fluid analysis experts might recommend you change your oil right away and to change it more frequently in the future.

High levels of copper (Cu), iron (Fe) and lead (Pb) could indicate abnormal wear of the bronze friction discs (if equipped) and steel separator plates. Recommendations would include stopping the machine and inspecting the transmission. Also, you would be advised to cut open and inspect the oil filter for large particles.

S?O?S Fluid Analysis Tests

S?O?S fluid analysis consists of four standard tests:

Component Wear Rate—What components are wearing and at what rate?

Oil Contamination—What contaminates are showing up in the oil?

Oil Condition—Is the correct transmission oil being used?

Has the oil been exposed to excessive heat?

Oil Identification—Is there coolant or water leaking into the oil?

Is the right oil being used?

Advantages of Using S?O?S Fluid Analysis

Surveys constantly show major benefits for regular users of S?O?S fluid analysis:

? Experts can provide analysis and interpretation of trends and can forecast any wear problems.

? S?O?S fluid analysis test results are available within 24 hours after receipt of the sample.

? Evaluation is supplied in an easy-to-understand test report, which calls for specific action and/or makes carefully outlined recommendations.

? Reports can identify problem areas such as careless maintenance or an operator who rides the brakes too much.

? Using S?O?S fluid analysis saves time and money because potential trouble spots can be identified before they become major problems. Consult your Equipment dealer for complete information and assistance on the S?O?S fluid analysis program.

PREVENTIVE MAINTENANCE

Regular preventive maintenance is the most cost-effective way to keep your transmission operating at peak performance. Preventive maintenance focuses on transmission and drive train oils, filters, S?O?S fluid analysis and contamination control.

Benefits include:

? Ability to schedule downtime and plan for maintenance and repair costs.

? Help prevent major failures, including failures of related parts.

? Save money by driving more repair before failure.

? Maximize parts reusability.

? Optimize equipment life to keep your machine on the job.

? Increase machine resale value.

Following a good preventive maintenance plan can significantly increase transmission life.

OIL USE

Oil helps to perform three main functions: cleaning, cooling and lubricating the transmission. Today’s transmissions feature new metals, elastomers, and friction materials that require advanced lubrication. You must use the right oil and change it regularly and properly to achieve top performance.

USE THE RIGHT DRIVE TRAIN OIL

Transmission/Drive Train Oil (TDTO) is specially formulated to increase the life and performance of your drive train components. This oil reduces transmission slippage, controls brake chatter, provides greater machine rimpull and increases friction material life up to 45 percent.

TDTO surpasses the TO-4 specification requirements and is specified as factory fill for all machine compartments where TO-4 oils are the primary recommendation.

Equipment Manufacturer also offers a multi-season formulation of TDTO called TDTO (TMS). This formulation exclusive is a partially synthetic lubricant that eliminates the need to change oil at seasonal intervals. As a result you use the oil for its full life, so there’s less used oil disposal and less downtime for maintenance.

TDTO (TMS) has shown improved transmission performance in cold weather for machines with electronic controls. TDTO (TMS) is recommended in climates with widely ranging ambient temperatures to avoid unnecessary oil changes.

For extreme cold climates, Equipment manufacturer offers TDTO Cold Weather? oil. This oil is a synthetic blend that provides superior performance and protection in transmissions, torque converters, final drives, hydraulics, and/or wet brakes at temperatures down to -40°F (-40°C). The special formulation creates optimal friction performance and controls transmission slippage while eliminating clutch glazing.

Some machines call for the use of multipurpose tractor fluid in the transmission. For these applications Equipment manufacturer offers MTO oil.

CHANGE OIL PROPERLY

Changing oil properly and at correct intervals is critical to realizing maximum component life. Actual oil life is determined by many factors such as operating conditions and applications or contamination control.

You can reduce contamination by:

? Washing the transmission tank and drain before removing cap.

? Draining oil as quickly as possible and doing so when it is agitated and warm.

? Using a filtered transfer cart to add new oil.

? Installing and removing filters carefully.

? Keeping filters in the package until ready for use.

? Cutting open and inspecting used filters before installing new ones.

FILTERS

Filters are specifically designed around key factors such as sediment capacity, collapsibility, burst strength, and pressure fatigue. By properly and regularly changing filters and by selecting the right filters, you maintain drive train system cleanliness, reduce component wear, and lower costs. For better control manufacturers  recently introduced a new line of transmission filters which have been designed to meet the specific needs of transmission applications. These new filters feature synthetic media which provides significantly higher dirt holding capacity and better cold weather performance. Prior to this line of filters, transmissions systems had used the same filter as the hydraulic system.

Now a days Manufacturers also offers Ultra High Efficiency Filters which can be used as a cleanout filter after any maintenance, rebuild, or debris invasion, or when suggested by particle count data from S?O?S fluid analysis. If a cleanout filter is used, remember to switch back to a standard filter within the recommended hour interval. When replacing an old transmission filter it’s extremely important to cut open the filter and inspect for signs of component wear or clogging. Pieces of metal may be found in or around the magnetic screen and can indicate a certain component is failing.

POSSIBLE SOURCES OF METAL PIECES.

 ? Aluminum—torque converter

? Bronze colored—transmission clutches

? Gray iron—transmission housing or pistons

? Brass—rings in rotating clutches

? Shiny metals—gear teeth

? Shiny flaky material—bearings

BREATHERS

Breathers are extremely important in transmission preventive maintenance. If breathers become plugged and temperatures dip down during the evening, the transmission becomes a vacuum because the cool air inside the transmission case shrinks. As it shrinks, it draws in air, dirt and other contaminants through the gaskets and seals. If this occurs regularly, the gaskets and seals may sustain enough damage to allow water and other contaminants into the transmission. Dirt and water can be especially harmful to the electronics. Solenoids in your electronics control when and how quickly your clutches engage. When the solenoids become contaminated they become sluggish and your clutches may engage too quickly or they may slide. To get the most use out of this filter, cover the transmission breather before washing your equipment and check your breather for clogging when inspecting other machine components.

PREVENTIVE MAINTENANCE CONTAMINATION CONTROL

You demand more power, faster cycle times and easier operation. Equipment manufacturer is responding with higher system pressures and more sophisticated, productive machines. Controlling contamination is more critical than ever because these high-tech machines require tighter clearances and fluid systems that are more sensitive to contamination. Contamination leads to reduced efficiency, increased cycle times, shortened component and fluid life, and catastrophic failure causing costly downtime and repairs.

 As an example, only 1/2 teaspoon of “dirt” is allowed in a 55-gallon drum of oil before quality standards are exceeded.

CAUSES OF CONTAMINATION

Contamination can be introduced at the refinery, during machine operation or during maintenance. Contaminates include:

? Dirt

? Heat

? Sealing material

? Air

? Metals

? Paint flakes

? Grease

? Water

? Products from oil oxidation

 ? Rag fibers

? Weld spatter

EFFECTS OF CONTAMINATION IN TRANSMISSIONS

? Shifting problems from plugged control valves

? Premature clutch wear from spinning

? Leaks or premature wear

? Premature bearing wear or bearing failure

? Premature gear wear

PREVENTING CONTAMINATION GOOD HOUSEKEEPING PRACTICES

? Sweep floors daily.

? Clean up spills immediately.

? Keep workbenches uncluttered and free of debris.

? Limit use of floor storage.

PROPER OIL STORAGE AND TRANSFER METHODS

? Filter new oil.

? Store oil drums on their sides.

? Use drum covers.

? Use “kidney loop” system.

? Use high efficiency filters for extra filtration.

REPAIR AND ASSEMBLY

? Place covers over open compartments.

? Ensure that root cause of failure has been identified and repaired.

? Properly clean components before reassembly

? Use standard parts kits for all component installations.

PARTICLE COUNT MONITORING

? Strive for oil cleanliness.

? Test oil in new machines after field assembly or after adding new attachments.

? Test oil before and after service repair

THOROUGH INSPECTION

A good inspection program combines your daily inspections with our periodic in-depth analysis.

? Locate potential problems before they become major repairs.

? Schedule transmission maintenance and service.

? Plan and control your operating costs and downtime.

Your daily visual inspection routine should include a complete visual and operational check of your transmission.

REPAIR INDICATORS

S.O.S. fluid analysis

Service meter hours

Operator observation

PROBLEM INDICATORS   CAUSES

Hesitation/ Slippage   Causes i. Worn plates and discs ii. Linkage out of adjustment, iii. Low fluid level, iv. Linkage not free, v. Incorrect pressure settings, vi. Wrong oil used,

Unusual Noises     Causes i. Worn gears/bearings, ii.Dirt entry, iii. Aeration/cavitation

iv. Low fluid levels

Vibration           Causes i. Bent/damaged drive shaft, ii.Gear failure,

iii. Bearingfailure          

Overheating      Causes i. Wrong oil used, ii. Plugged radiator,

iii. Worn pump/pressure relief valve, iv, Worn or damaged seals

v.  Low fluid level, vi.  Worn or dirty control valve             

Debris on filter     Causes i. Dirt entry, ii. Wrong oil used,

iii. Extended oil change period, iv.  Worn gears/bearings, v. Disc disintegration           

Leaks       Causes i. Worn, Hard, Cracked seals            

TRANSMISSION MAINTENANCE TIPS

DO

 1. Use proper Contamination Control guidelines.

2. Make sure the fluid meets ISO standards before pouring it in your machine.

3. Use the correct transmission oil—Manufacturers recommended fluids found in the Operation & Maintenance Manual.

4. Use Filters—Recommended filters found in the Operation & Maintenance Manual.

 5. Cut open old filters to inspect for indications of a problem.

6. Keep accurate records.

7. Follow the proper service hours guidelines.

DON’T

1. Don’t open your transmission system in a dirty environment.

 2. Don’t abuse your machine (application, operation, etc.).

3. Don’t pre-fill filters (fuel or oil).

MAXIMISE THE LIFE OF TRANSMISSION

For any machine to be safe, reliable, and productive, regular preventive maintenance is vital. It is the most cost-effective way to keep your transmission operating at peak performance. If you take care of your transmission, then gears and shafts can last through multiple rebuilds and the overall transmission life increases. Take a proactive approach by planning for scheduled downtime, maintenance, and repair costs. When you plan, you save money and time—and who couldn’t use more of each?