The Banjo twist and turn.

The Banjo twist and turn.

"These build journal entries are part of a Special Series on the DCT major service, updated GTS filling specifications and upgraded, oversized, DCT pans

This journal entry documents the installation process of the OE+ DCT GTS main oil pan and its GTS Banjo bolt, the filling procedure  along with my fluid recommendations."
- Matt

Banjo who?

The banjo bolt is made to allow overfill of the main oil pan as the fill point sits higher than your OEM fill plug. 

The banjo bolt included in the OE+ DCT GTS main oil pan kit comes with everything you need to install this, and help you fill the pan: 

  1. The threaded, holed bolt.
  2. The "banjo".
  3. The 2x washers. 
  4. The cap. 
  5. The filling adapter. 

You torque this black bolt to the casing per OEM specs. 

Fitting the GTS style Banjo Bolt.

The GTS style Banjo Bolt takes place for the main fill plug on the right side of your DCT. 

Look for the main fill plug by the lower left of the side pan, near the green sticker. 

Make sure you have a washer on each side. This shows the filling adapter fitted. 

This shows the banjo bolt with the treaded cap. This is the final look. 

The Filling Process.

I assume you've fitted the transmission back on, haven't filled any transmission fluid off the car, properly bolted and triple checked your torque specs of the transmission itself and properly refitted all coolant lines. 

Congratulations, you're nearly there. 

The official BMW process. 

BMW officially recommends this to be accomplished using the dealership GT1 tools. 

My understanding is this tool allows the tech to monitor the transmission temperatures as they deem it critical to precisely measure the fill rate of the transmission. 

The reason is thermodynamics. 

The process we used. 

You will need a few simple tools to perform the fill process when doing it the DIY way. 

  1. Fluid pump
  2. Fluid thermometer
  3. Minimum of 9x liters of DCT fluid

Before you begin the process, make sure the drain plug on your new pan is properly torqued. 

Step 1: Fill her up cold.

Using the pump, fill up the pan with the engine off until it drips from the Banjo bolt fill plug. 

The fluid must be below 90F. 

Step 2: Heat her up and fill her up hot. 

Start her up, maintain 2,000 RPM for 1 minute. 

Using the pump, fill up the pan with the engine off until it drips again from the Banjo bolt fill plug. The fluid must be below 104F. 

Reassemble, test drive and re-check torque specs & any leaks. No coding or adaptations are needed. It is recommended to run the DCT adaptation as fluid plays a major role in the transmission's operations.

If it all checks out, you're good to go. 

Notes on fluid. 

We had 9 liters of LiquidMoly 8100 Series DCT fluid ready to go. This beyond what is usually needed as we needed to account for 2 things:

  1. We overfilled from OEM specs by 1.8 liters. 
  2. We needed to account for fluid loss from the coolant hose change. 

The LiquiMoly fluid is inexpensive enough and readily availably for you to overstock on it. 

Up next: my DCT lasted a while, until its clutches let go.

We revisit this with another transmission. 

Guess what? The replacement DCT leaked too. 

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