1981/04/20 Caterpillar

Different Check Valve Gives Faster Shifts{3313}

Usage:

7251, 7261, 7271 Marine Transmissions

Description of Change: A different check valve is used in the control valve group for 7251, 7261 and 7271 Marine Transmissions.

The new check valve uses three plugs with larger orifices. See the Illustration. The larger orifices permit a faster pressure increase so the clutches engage faster. The pressure increase takes approximately 5 seconds with the new valve in comparison to 7 seconds with the former valve.

The result is less clutch slip and decrease of the heat caused by friction.

Adaptable As: The new 6L2107 Valve Assembly is a direct replacement for the former 7L5390 Valve Assembly in the 3N4485 Control Valve Group. The 7L5390 Valve Assembly is still available for use in other applications.

Location of the 6L2107 Valve Assembly.

Caterpillar Information System:

1981/04/13 Correct Installation Of Seal Spacer In Gear-Type Hydraulic Pumps{5073}

1981/04/13 FT1585 Plate Can Be Fabricated For Governor Spring Guide Replacement{0626}

1981/04/13 Check Operation Of Hydramechanical Shutoff At Specific Intervals{7418,7525}

1981/04/13 New Ahead Main Shaft Assembly Gives A Tighter Fit; Dimensions For The Fit Of Shafts And Gears{3300}

1981/04/13 Use Two Wrenches On Fuel Line Nuts{1254,1252}

1981/04/13 New 6V3060 EGR System Tester Group Available{1080}

1981/04/13 Use 6V4058 Universal Extension To Remove And Install Starter Bolts{0612}

1981/04/06 Improve Use Of Engine Service Manual Microfiche{0374}

1981/04/06 New Piston Ring Assemblies Give Improved Ring And Cylinder Liner Life{1215,1213}

1981/04/06 Correct Refill Capacity For Engine Oil{1318}

1981/04/06 Cooling System Cleaner Removes Rust And Corrosion{1350,1353,1354}

1981/04/06 Use Heat-Indication Products To Measure Parts Temperatures{0651}

1981/04/20 Storage Compartments For Maintenance (Lubrication And Maintenance) Guides{7312}

1981/04/20 6V4020 Piston Ring Expander Group Available{0622,1215,1214}

1981/04/20 Use 6V4173 Clamping Bar Group On Hydraulic Hose Press{0624}

1981/04/20 Stronger Fitting Used With Sending Unit For Oil Pressure Gauge{7457,7451,3310,3314}

1981/04/27 Use 6V4089 Reamer Assembly To Clean Nozzle Bores{0622}

1981/04/27 Replacement Thermostat, Element Assemblies Available For Jacket Water Heater{1383}

1981/04/27 Fuel Injection Test Bench Specification Sheets Changed{0652}

1981/04/27 Special Instruction Available For The Use Of The 6V4040 Nitrogen Tire Inflation Group{4203,0374}

1981/05/04 Larger Valve Springs{1108,1101,1252}

1981/05/04 Automatic Shut-Off Systems Not Recommended on Mobile Earthmoving Equipment{7418,7403}

1981/05/04 Crankshaft Failures; New Thrust Plate{1203,1202,1230}

1981/05/04 Use 6V4057 Grease Gun Adapter In Difficult Access Areas{0671}