- 02/02/2017
- 1 Min Read
- By: Gareth Foley
Automatic Transmission Fluid Level Check for GM-Transmission BMWs (E34, E36, E37)
This procedure is outlined for the GM-built automatic transmissions that were commonly installed with many six-cylinder engines in the 1990s era 3-Series (E36), 5-Series (E34), and Z3 (E37). To BMW nerds, these are known as the A4S-270R or the A4S-310R transmissions. But they are also commonly referred to as the GM-4L30E. These units were built in Europe, and variants were sold in other cars, including the Cadillac Catera (“The Caddy that Zigs!”) and multiple Isuzu trucks and SUVs.
The 4L30E transmission is most easily identified by its dual sump pans. Here, it is shown in an early 1990s 525i. But the procedure will be similar across the other body styles.
Many of the GM and transmissions made for BMW do not have a fluid dipstick. The level is checked in a way somewhat similar to how you check the fluid level on a manual transmission.
A few basic warnings:
1. This process must be done in a well-ventilated area since it involves running the car’s engine. In my case, I kept both garage doors open and used two box fans to circulate fresh air through the garage.
2. Allow your transmission to cool off before attempting this procedure. Hot ATF can burn you.
3. Never turn off the engine while the fill plug is removed from the transmission pan. This will simultaneously shut off the pump inside the transmission, and all of the ATF circulating through the unit will immediately drain back into the pan and onto your garage floor. Don't ask how I learned this.
Tools
- Floor jack
- Four jackstands
- Thermometer
- 17 mm socket
- 19mm socket
- Torque wrench
- ATF transfer pump
- Paper towels
Parts
New washer (optional)
Fresh ATF
Note: Check your car’s ATF requirement. Most years used a Dexron III fluid, but some used Texaco 7045-E. If you are unsure of which fluid to use, FCPeuro offers universal ATF.
Checking and topping off your ATF level
Raise the car on jackstands. The vehicle must be sitting level to get an accurate reading.
Start the vehicle from cold.
Set the parking brake. Put the transmission in neutral. Allow it to idle for a few minutes as the ATF warms up.
Remove the ATF fill plug. This is the large bolt located toward the upper rear driver side of the transmission sump.
The transmission fluid should be between 85 and 130 degrees Fahrenheit when the fluid level is checked. Use either a digital infrared thermometer aimed inside the fill hole or an analog thermometer that has a probe and that can be slipped into the transmission’s fill hole.
Monitor the temperature with a thermometer.
If a small trickle of fluid does not come out of the fill plug when the ATF reaches 85- 130 degrees Fahrenheit, the transmission ATF level is low. Use a transfer pump to add fluid until you see a small trickle from the fill plug.
Reinstall the fill plug.
Put the transmission in park. Turn off the engine.
Lower the car. Take it for test drive.
While you are down there
Check for leaks around transmission sump gaskets.
Inspect driveshaft bushing for cracks.
