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View Full Version : How to flush your torque converter



joecar
January 30th, 2006, 09:49 AM
When do you own transmission fluid/filter change, you can also change the fluid in your torque converter
(i.e. replace all the fluid, not just what falls out of the pan).

You will need at least 12 quarts of ATF (have 3 extra quarts handy just in case).

0. Get a 5 gallon bucket and "calibrate" it by marking off and numbering quarts.

1. Replace filter, pan, fluid, do not start engine yet;
make sure you have put in at least the same amount of fluid you took out, 4-5 quarts.

2. Undo hose clamp on cooler return line, pull hose from hard line, and direct hose into calibrated bucket
(if necessary use an extension hose or tube to reach bucket);
F-body has this hose clamp on the cooler return line; I don't know about other models.

3. Start engine, and while observing bucket, pour quarts of new fluid into fill tube (via funnel)
at same rate as bucket is filling (or faster) until at least 8 quarts are in bucket
(or until you see new fluid in bucket), then turn off engine.
See note below.

4. Reconnect hose and hose clamp to hard line.

5. Start engine, select each gear briefly, check fluid level in Park, check for leaks.

Note:
In step 3, you must have your new ATF bottles open and ready (number the bottles with a marker);
the fill tube and/or funnel may slow down the rate at which you can pour in ATF...
if you can't keep up, turn off engine after 2 quarts, pour in 2 quarts, restart engine,
and repeat every 2 quarts until bucket contains at least 8 quarts (or until you see new fluid).

Don't let the transmission pan run dry!!

This procedures flushes the converter because the converter fluid exits thru
the TCC valve into the cooler circuit (and not into the pan).

The cooler return line feeds the lube circuit which requires fluid flow only if
the gearsets and output shaft are loaded and turning (i.e. in gear).

This procedure works for the 4L60-E and 4L80-E, and may work for other transmissions in other vehicles,
depending on what circuit is fed by the cooler return line (check the hydraulic diagram).

joecar
March 6th, 2006, 09:23 AM
Diagram showing hose clamp on cooler return line (F-body).