January 30, 2018

GM & BMW 6L80 Family Identification Guide

This identification guide covers GM 6L45, 6L50, 6L80 and 6L90 valve bodies, plus the BMW early- and late-style transmission separator plates.
6L45/50 Early-Style ('10-Earlier) Upper Casting
6L45/50 Late-Style ('10-Later) Upper Casting
6L80 Early-Style ('10-Earlier) Upper Casting

Note: 6L90 Early-style ('10-earlier) also have the exhaust slots like shown above.

6L90 Late-Style ('10-Later) Upper Casting

Look for machined-down boss (A, B, C or D) on the upper casting. Generally, if the A boss is machined down, this indicates an MYA/6L45 (see chart below). This identification system is not foolproof, as some valve bodies do not have any bosses machined down.

Machined-Down Boss on Upper Valve BodyIndicates Valve Body Unit*
"A" Boss IDMYA/6L45
"B" Boss IDMYB/6L50
"C" Boss IDMYC/6L80
"D" Boss IDMYD/6L90
*Note: This is a general rule to follow, but may not always be true. Sometimes no bosses are machined.
6L45-6L90 Early-Style ('10-Earlier) Lower Casting
6L45-6L90 Late-Style ('10-Later) Lower Casting

Upper Casting NumberCenter Support Feed HolesLower Casting Number

6L8094040955Offset Front95810945
6L9094040955Offset Rear95810945
Centered9581 or 6351

BMW Early Separator Plate
BMW Late Separator Plate

BMW early versus late applications have a separator plate variation in the converter circuit. At this time, there are no known year breaks or external identification features that can be provided.

Related Units

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