Transfer Case Repair Kit for Retrofitting Oil Drain Plug on BMW ATC35L Transfer Cases

Special tool kit designed for retrofitting an oil drain plug to BMW ATC35L transfer cases used in xDrive all-wheel-drive vehicles.

Many BMW F-series xDrive models suffer from premature transfer case failures. Common causes include:

• Transfer case wear caused by aged transmission oil
• Wear particles from clutch friction materials
• Oil oxidation caused by moisture contamination

BMW specifies these transfer cases as lifetime-filled units and no oil drain plug is installed from factory. As a result, changing the transfer case oil normally requires complete removal of the transfer case.

This repair solution was developed in cooperation with professional workshops to enable efficient servicing of these transfer cases.

Integrated Precision Drilling and Milling System

The kit includes a specially designed holding bracket with drill guide sleeve acting as a precision template.

The system determines the exact drilling position and drilling depth required for the retrofit process.

The included drilling and milling tool simultaneously:

• Drills the housing opening
• Mills a flat sealing surface for the drain plug sealing ring
• Creates an internal chamfer for easier thread cutting

The transfer case can later be refilled through the upper filling plug using a hook-style filling adapter and hand pump.

Installation Procedure

• Attach the drilling template bracket to the transfer case
• Screw in the drill guide sleeve until seated
• Drill and mill the housing using the supplied tool
• Fully drain the transfer case oil
• Apply grease to the thread tap and cut the thread into the housing
• Install the drain plug and tighten to 10–15 Nm

Compatible Transfer Cases

Suitable for:

• ATC35L

Reference numbers:

• 27105A371F3
• 27105A4A093
• 27108612557
• 27108643150

Compatible BMW Vehicle Models

Suitable for the following BMW models:

• 1 Series: F20, F21
• 2 Series: F22, F23
• 3 Series: F30, F31, F34, F35
• 4 Series: F32, F33, F36
• 5 Series: F07, F10, F11, F18
• 6 Series: F06, F12, F13
• 7 Series: F01, F02
• X1 Series: E84
• X3 Series: F25
• X4 Series: F26
• X5 Series: F15, F85
• X6 Series: F16, F86

Package Contents

• 1 x item.no. 123154 Angle drilling template bracket
• 1 x item.no. 123154 Drill guide sleeve
• 1 x item.no. 123154 Drill and milling tool with depth stop
• 1 x item.no. 123154 M8 x 1 finishing thread tap
• 1 x item.no. 123204 Drain plugs M8 x 1 with sealing rings, 5-piece set*
• 1 x item.no. 115268 Storage case

*Drain plugs are available separately as a 5-piece set under the specified item number.

Tool Reference Number

To be used as:

• BMW 27105B8C3E4

Product Features

• Stahlmaxx quality tool
• High-quality precision-manufactured components
• Spare parts available
• Designed for professional workshop use

Original numbers are provided for comparison purposes only. This is not an original BMW tool.