TSB: K005/98

AUTOMATIC TRANSMISSION COOLER LINE FLUSHING PROCEDURE

APPLICABLE MODELS

All models with automatic transmission.

DESCRIPTION

Automatic transmission (A/T) oil cooler/lines must be power flushed completely before an overhauled or replacement A/T is installed. One of the causes of repeat A/T failures is an internal automatic transmission fluid (ATF) restriction at the inlet side of the oil cooler. This restriction is usually caused by an accumulation of metal particles and debris (from a previous A/T failure) on the internal mesh type baffle of the oil cooler. Power flushing will remove the restriction by back flushing the cooler/lines followed by forward flushing to ensure full ATF flow. See FIGURE 1 of a typical ATF cooler.

CAUTION: Repeat repairs caused by improper or lack of cooler line flushing will not be covered under warranty.

RECOMMENDED EQUIPMENT

PRECAUTIONS

Before power flushing, inspect the hoses/lines and clamps. Power flushing must begin with back flushing followed by forward flushing to quickly dislodge the restriction. If back flushing is not performed before forward flushing, the restriction could further reduce the ATF flow through the internal mesh type baffle of the cooler and flushing will not be effective or possible.

Inspect Oil Lines Clamps

Be sure to inspect the lines (hoses/pipes) for cuts, crimps (pinched), cracks or any other damage before reusing them. If any problem exists or the hose comes off when applying oil pressure, replace it.

CAUTION: Always use new clamps when replacing hoses.

BACK FLUSHING

1. Using the Power Flushing Equipment manufacturers instructions, connect equipment so the flushing fluid flows in the opposite direction of normal fluid flow. Refer to page 4 to determine normal fluid flow. See typical example of back flushing flow in Figure 2.

2. Flush oil cooler/lines until discharge fluid is clean.

NOTE: If the cooler can not be properly flushed using recommended equipment, send the radiator out for sublet cleaning or replace. Refer to the WSM or Automatic Transmission Quick Reference Guide (P/N 9999-95-4501-96) for exact location of cooler line inlet./outlet fittings.

Forward Flushing

1. Connect power flushing equipment so the flushing fluid flows in the direction of normal fluid flow. Refer to page 5 to determine fluid flow. See typical example of forward flushing flow in FIGURE 3.

2. Flush oil cooler/lines until discharge fluid is clean.

WARRANTY INFORMATION

NOTE: This information applies to verified customer complaints on vehicles covered under normal warranty. Refer to the SRT microfiche for warranty term information. When you submit a warranty claim on automatic transmission complete replacement, add any of the following operation numbers and labor hours to the operation number and labor hours for automatic transmission complete RR.

TYPICAL AUTOMATIC TRANSMISSION / TRANSAXLE NORMAL FLUID COOLER FITTING LOCATIONS

REFER TO THE WORKSHOP MANUAL FOR SPECIFIC DETAILS