8L90E Specs, Performance, and Identification

8L90 M5U Specs

The 8L90E is an 8 speed automatic transmission developed by General Motors and introduced for the 2015 Model year.  It is currently phasing out the 6L80/6L90 transmissions (although it hasn’t done its all the way yet.  Structurally, the 8L90 is similar to the 8L45, except that it is made to handle more power and torque.

It is an incredibly advanced transmission and has the technology to perform at a high level in the Corvette, while at the same time being cost effective enough to use in high volume production.

The addition of two extra gears over the previous generation 6L80 was necessary to meet ever tightening Federal fuel economy laws.  The addition of the two extra gears allows the 8L90 to realize a real world 5% fuel economy improvement over the 6L80.

Navigation

Gear Ratios

Specs

Performance

Identification

Applications 

 

8L90 Gear Ratios

1ST4.56
2ND2.97
3RD2.08
4TH1.69
5TH1.27
6TH1.00
7TH0.85
8TH0.65
Reverse3.82

8L90E Specs

Like most GM automatic transmissions that have come before it, the 8L90E has an aluminum case, overdrive, and can handle a lot of power.  Through a combination of lightweight materials and wizardry, GM engineers were able to get the 8L90 to weigh in a couple of pounds less than the 6L80E, and keep it roughly the same size.

The max power and torque specs bump up a little when it is put behind the LT1/LT4 engines.  There’s more on this specific version of the transmission below.  Or use this link to take you there.

8L90 Specifications

RPO CodeM5U
ManufacturerGM
Production Years2015+
Number of Gears8 forward
Maximum RPM7000
Max Torque635 lb-ft
Max Horespower650
Max Transmission Torque738 lb-ft
Length
Case2 Piece Aluminum
Computer Control?Yes, External TCM
Weight210+ Pounds
Max Shift Speed RPM7000
Max GVW13,200
Max GCVW20,500
Tourqe converter258mm, locking
ATFDexron High Perormance

 

8L90 Performance

The 8L90 has four different gears sets and five clutches.  This allows for extremely tight shifts in a relatively small space.  The 8L90 offers a true manual paddle shifting experience.  And unlike the the Corvettes rivals at Porsche and Ferrari, the 8L90 also goes to work in pickup trucks.  Thats a lot of range to engineer into one transmission.

  • All models come with adaptive shift control
  • Highly efficient axis binary pump
  • Performance algorithm shifting
  • Performs like a clutches gearbox in manual mode
  • Redline shift protection
  • Utilizes VFS to monitor clutch pressure for more precise shifts
  • Adapts to wear and tear and compensates electronically
  • Paddle shifting
  • Grade control

LT1 + LT4

The 8L90E is the transmission GM chose to put behind the ultra high performance LT1 engine.  There are a few minor differences between the standard version and the LT1.

  • Max Torque is increased to 644 lb-ft
  • Gear ratios stay the same
  • LT1 uses a slip yoke design
  • LT4 uses a fixed yolk design

Identifying an 8L90E

The easiest way to determine if your vehicle is equipped with an 8L90 is to utilize the RP0 codes.  They can be found in the glove compartment of the vehicle in question.

You’ll want to find the code M5U.  That is proof positive that the vehicle in question was at a minimum equipped with the 8L90 from the factory.

 

8L90E Applications

Since the 8L90 has only been available for a few model years(production started in 2014 for the 2015 model year). It is not utilized in many vehicles.  It is only used in high performance vehicles and performance cars, otherwise the 8L45 is more than enough for the job.

 

Make and ModelModel YearsFinal Drive RatioNotes
Cadillac Escalade [2]2015–20173.23
Chevrolet Corvette (C7) Stingray [3]
2015–present
2.41Standard
2.73 (Z51)Z51
Chevrolet Corvette (C7) Z06 [4]2015-current2.41
Chevrolet Silverado/GMC Sierra[5]
2015–present
3.23Standard
3.42Towing Pacage
GMC Yukon Denali/Denali XL2015–20173.23
Cadillac ATS-V2016–present2.85
Cadillac CTS-V2016–present2.85
Cadillac CT62016–present3.27
Chevrolet Camaro2016–present2.77
Chevrolet Colorado/GMC Canyon[6]2017–present3.42