This information guides you through the key characteristcs and differences between BMW 8HP 45 / 50 / 51 / 70 / 75 / 76 / 90 / 95 transmissions

It describes the different bellhousings, different torque converters, oil cooler ports, output flange dimensions etc.

Please be aware! All information here is based on the 3D scans we made and information we collected from these, that being said all information might not be 100% correct. 

Last updated: 2024-04-17

Identify your transmission

Start by looking at the left hand side of the transmission, in the rear bottom (A). You will find some numbers, the last row identicates the transmission model. 

Identify your oil cooler port size (B) in mm. Identify the mounting thread size, M6 or M8.

Identify the output flange PCD and insert size. Not applicable on AWD transmissions.

Identify the length of the transmission (D).

Use our Transmission Technical Information page to see reference measurements on all the above dimensions.

BMW 8HP45 (Gen 1)

There are four different 8HP45 variants:

- 8HP45 from N55 engine
- 8HP45 from N20 engine
- 8HP45 from N13 engine
- 8HP45 from N47 engine

BMW 8HP45 N55 F-series

This transmission has the N20/N55 bellhousing bolt pattern. It has a smaller converter with a flat mounting face, fastened with 6x M10 bolts. 32mm guiding nose.

It has 18.5mm oil cooler ports, uses a M8 mounting bolt for the oil cooler adapter.

Output flange is 105.0mm PCD and insert size of 22mm.

BMW 8HP45 N20 F-series

This transmission has the N20/N55 bellhousing bolt pattern. It has a smaller converter with a C-shaped mounting face, fastened with 6x M10 bolts. 32mm guiding nose.

It has 18.5mm oil cooler ports, uses a M8 mounting bolt for the oil cooler adapter.

Output flange is 105.0mm PCD and insert size of 22mm.

Note! This pictures features the N55 6-bolt converter, not the C-shaped N20 converter.

BMW 8HP45 N13 F-series

This transmission has a unique bellhousing bolt pattern only available on N13 engine.. It has a smaller converter with a flat mounting face, fastened with 4x M10 bolts. 16mm guiding nose.

It has 18.5mm oil cooler ports, uses a M6 mounting bolt for the oil cooler adapter.

Output flange is 96.0mm PCD and have a flat mounting surface (No insert size).

BMW 8HP45 N47 F-series

This transmission has N47/B48/N57/B58/B57/S58 bolt pattern, which we normally refer to as N57 bolt pattern. It has a smaller converter with a flat mounting face, fastened with 4x M10 bolts. 32mm guiding nose.

It has 18.5mm oil cooler ports, uses a M6 mounting bolt for the oil cooler adapter.

Output flange is 105.0mm PCD and insert size of 22mm.

Note! This pictures features the N55 6-bolt converter, the N47 has 4-bolt converter.

BMW 8HP50/51 (Gen 2 / Gen 3)

So far we have identified 7 different 8HP50 / 51 Transmissions

- 8HP50 from B37 engine F-series
- 8HP50 from B38 engine F-series
- 8HP50 from B47 engine F-series
- 8HP50 from B48 engine F-series
- 8HP50 from B58 engine F-series
- 8HP51 from B47 engine G-series
- 8HP51 from B58 engine G-series

All the transmissions listed in this section share the same bellhousing pattern aka N57 pattern. It has a converter with a flat mounting face, fastened with 6x M10 bolts. 32mm guiding nose.

The F-series shares the same oil cooler ports size of 17.0mm and M6 thread size.

The G-series has the larger oil cooler ports of 18.5mm and M6 thread size.

BMW 8HP70/75/76 Small Bellhousing (Gen 1 / Gen 2 / Gen 3)

So far we have identified five different 8HP70 / 75 / 76 Transmissions with small bellhousing pattern (aka N57).

- 8HP70 from N57 engine F-series
- 8HP75 from N57 engine F-series (X5 X6 AWD)
- 8HP75 from B57 engine G-series
- 8HP76 from B57 engine G-series
- 8HP76 from S58 engine G-series

All the transmissions listed in this section share the same bellhousing pattern aka N57 pattern. It has a converter with a flat mounting face, fastened with 6x M10 bolts. 32mm guiding nose.

Output flange is normally 105.0mm PCD with 22mm inserts both F- and G-series.

The F-series shares the same oil cooler ports size of 17.0mm and M6 thread size.

The G-series has the larger oil cooler ports of 18.5mm and M6 thread size.

 

BMW 8HP70 / 75 Big Bellhousing (Gen 1 / Gen 2)

So far we have identified two different 8HP70 / 75 Transmissions with big bellhousing pattern (aka N63)

- 8HP70 from N63 engine F-series
- 8HP75 from N63 engine G-series (AWD)

All the transmissions listed in this section share the same bellhousing pattern aka N63 pattern. It has a converter with a C-shaped mounting face, fastened with 6x M10 bolts. 32mm guiding nose.

8HP70 F-series has a output flange PCD of 110.0mm and 18.0mm insert size. 
It features the larger oil cooler ports with 18.5mm and mounting thread size is M8.

BMW 8HP90 / 95 (Gen 1 / Gen 2)

So far we have identified two different 8HP90 / 95 Transmissions

- 8HP90 from N74 engine F-series
- 8HP95 from N74 engine G-series (AWD)

All the transmissions listed in this section share the same bellhousing pattern aka N74 pattern. It has a converter with a C-shaped mounting face, fastened with 6x M10 bolts. 32mm guiding nose.

8HP90 F-series has a output flange PCD of 110.0mm and 18.0mm insert size. 
It features the larger oil cooler ports with 18.5mm and mounting thread size is M8.