1981/05/20 Caterpillar


Different Check Valve Gives Faster Shifts

Usage:


7271, 7261, 7251 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:

1981/05/20 List Of Service Publications
1981/05/20 Larger Valve Springs
1981/05/20 6V4020 Piston Ring Expander Group Available
1981/05/20 Crankshaft Failures; New Thrust Plate
1981/05/20 New Tool Makes Glow Plug Wire Removal Easier
1981/05/20 Safety: Battery Vent Caps
1981/05/20 Change Made To Power Take-Off Adapter Housing
1981/05/20 Replacement Thermostat, Element Assemblies Available For Jacket Water Heater
1981/05/20 Remove And Install Cam Bearings With 6V4077 Cam Bearing Tool Group
1981/05/20 Use 6V4069 Body Group To Remove Tapered Drive Sleeve
1981/04/22 6V3197 Spacer, 6V3041 Tool Group Available For Use During Removal And Installation Of Piston Pin Bearings
1981/04/22 Improve Use Of Engine Service Manual Microfiche
1981/05/20 Installation Of Rear Bearing Oil Seals In 3N6542, 3N8617, And 3N8618 Rear Power Takeoff Clutch Groups
1981/05/20 Use 6V4089 Reamer Assembly To Clean Nozzle Bores
1981/05/20 Hardened Nuts And Higher Torque Now Used In Ahead And Astern Clutch Groups
1981/05/20 Washer Added Between Bolt And Thrust Plate For Oil Pump Idler Gear
1981/06/03 Replacement Bushings For Delco-Remy Electric Starting Motors Must Be Machined For Correct Clearances
1981/06/03 Use Correct Specifications To Check Piston Ring Gaps
1981/06/03 New Cover Assembly And Gasket Used In Oil Pump Group
1981/06/03 Locks No Longer Used On Flywheel Bolts; New Torque Specifications For Flywheel Bolts
1981/06/03 New Mounting Group For Overspeed Switch
1981/06/03 Remove Direct Injection Fuel Nozzles With 6V4061 And 6V4054 Nozzle Pullers
1981/07/01 6V3145 Leveler Now Available
1981/07/01 Correct Use Of Keystone Ring Groove Gauges
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