The Banjo twist and turn.

The Banjo twist and turn.

"In this Special SeriesI document my various experiences with DCT leaks, failing clutches, and their solutions, including the  GTS Motorsport Oil Pan Kits

This journal entry documents the installation process of the GTS Banjo bolt, the GTS filling procedure along with my fluid recommendations for your installation of the GTS Motorsport Oil Pan Kits."
- 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 GTS Motorsport Oil Pan Kits kit comes with everything you need to install it: 

  1. The threaded, holed bolt
  2. The "banjo"
  3. The 2x copper washers
  4. The cap

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

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 GTS filling processes.

The filling process can begin once the transmission is fully bolted and connected to the car, with no fluids beyond any that may remain from the DCT cooler hoses. Before you begin the process, make sure the drain plug on your new pan is properly torqued. 

There are various processes to filling the GTS, I outlined 2x below. 

Notes on DCT fluid. 

Before proceeding, be aware that the original BMW fluid is expensive, and often in short supply.

As of 2021, various oil manufacturers have developed DCT compatible fluids, notably LiquiMoly and Motul. I had rapid access to LiquiMoly at a great price and opted for this. For clarity, I have no preference regarding DCT fluids. 

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 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. 

It's the most precise method to achieve filling specifications. 

The DIY process.

The DIY process makes due with accessible tools to replace the software used by BMW. You will need a few simple tools to perform the fill process when using this method: 

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


My original DCT-001 lasted a while, until something else let go.

Up next: we revisit this with another DCT transmission, or two.

Obviously, they both leaked - it presented the ideal opportunity to improve upon the initial design of the pans. 

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