We were experiencing a slight reverse slam in our 1999 SW1. A reverse slam is the “clunk” of changing the gears in an automatic transmission from reverse to any other gear. In Saturn S-Series cars, this is a common problem – usually the culprit of not maintaining the maintenance schedule of the automatic transmission.
After reading countless stories and fixes for the Saturn automatic reverse slam problem, I did it today on our SW1.
Here are the steps:
Get the right fluids for the job. Standard ATF fluid, an additive, and an OEM auto transmission filter from Saturn. DO NOT use a standard auto filter.
Put the car up on ramps.
Loosen and/or remove the air box. This will give you easy access to the transmission filter.
Un-tighten the transmission drain plug.
Let the fluid drain in a pan.
Check the fluid colour as it drains.
Make sure you let it dribble to the end.
Clean up the drips.
Check the fluid colour in the pan for problems.
Take off the old filter. A filter wrench will help.
The old filter.
Apply a thin coat of transmission fluid to the new filter seal. Just like an oil filter.
Make sure you watch the transmission sensors and sensor wires when you put the new filter on.
Pour in your additive of choice. Then pour in the ATF.
Take the car off the ramps and chalk the back tires with the ramps.
Put the car in reverse with the parking break on. Let the car sit in reverse for 30 minutes – I just used my stove timer to keep track of the minutes. While waiting, this is a good time to clean up the mess, and to check the tire pressure, clean the wind sheild, etc. etc. DO NOT LEAVE THE CAR UNATTENDED WHILE IN REVERSE! Stick around for any problems.
After the 30 minutes, take it out for a spin around the neighborhood. Try regular driving, …backing up, …3-point turns. Anything that will mimic regular driving.
I did this procedure, and our reverse slam was reduced by 95%. I’m hoping this will postpone a valve body replacement for a year or so. In some cases it will completely make the reverse slam problem go away.