1982/09/27 Caterpillar

Screen Added To Oil Lines At Inlet Of Brake And Torque Converter Oil Cooler{1366,1365,1375,1376,3103,3154,3179,4257,4304,5057,5068}

Usage:

768C, 772B, 776 Tractors;
769C, 773B, 777 Trucks

Reference: "New Oil Balance Line Used Between The Oil Coolers For The Torque Converter And Brakes," Service Magazine, August 6, 1979, Page 6.

Put a mark through the February 22, 1982 Service Magazine article, "Screen Added To Oil Lines At Inlet Of Brake And Torque Converter Oil Cooler," on pages 8 and 9 and through its Supplement on page 8 of the March 22, 1982 Service Magazine.

Make a reference to this article which has added information.

Description of Change: A screen has been added to the oil cooler lines groups for the above models. The screen is installed at the inlet of the brake and torque converter oil cooler (separate oil coolers on 776 Tractors and 777 Trucks) to keep small metal particles and/or chips out of the cooler(s). Once in the cooler, the metal chips can damage the tubes with a cutting action. The cutting action is the result of chip movement and vibration caused by the rapid flow of oil through the cooler.

The new screen is to be inspected at intervals of 1000 SMU (Service Meter Units) or after a failure of a primary component in the system. The screen must be cleaned, or a new screen must be installed at this time. This can be done when the oil is changed in the transmission and hydraulic system. Also, if the temperature of the brake and hydraulic system oil is higher than normal, inspect and clean the screen, or install a new screen if necessary. This information will be added to Maintenance Guides during the next revision. Until the revision is complete, make a note to use this article as a reference.

Adaptable To: The new parts are in effect with the serial numbers shown in Chart A. They are directly adaptable to all earlier machines. Charts B, C and D show the parts needed for installation on the machines. The item numbers in Charts B, C and D are the same as those in Illustrations 2, 3, and 4 respectively. The numbers in parenthesis () are the quantities used at each location. The quantities in the charts are some times different than the quantities in the illustrations because some of the original parts are used again.

In all models, the 4T2694 Screens are installed, point end first, into the 6G2322 Elbows which are fastened to the cooler. The 5T3129 Elbows are fastened to the 6G2322 Elbows and hold the screens in place. See Illustration 1.

Illustration 1. Correct assembly of the 6G2322 Elbow, the 4T2694 Screen and the 5T3129 Elbow.

When the components are loosened to remove the screen for inspection and/or replacement, the serviceman must make sure the screen stays all the way in the 6G2322 Elbow until the components have been removed. If the screen comes out with the 5T3129 Elbow and the hose and elbow fall, the screen can be damaged.

It is important on 776 Tractors and 777 Trucks that the 6G2322 Elbow be installed exactly as shown in Illustration 4. The elbow on the rear of the left oil cooler must be installed so that the screen port (opening) is toward the front of the machine. For this reason, it must be turned 180° from its original position. The 6G2322 Elbow on the front of the right oil cooler stays in its original position so that the screen port opens toward the rear of the machine.

On 777 Trucks with Serial Numbers 84A1-84A530, the new balance line, shown in the August 6, 1979 reference article, must be installed. But, use a 5T3168 Hose Assembly instead of the 6G2293 Hose Assembly shown in the parts chart in the reference article.