Chevy Silverado Transmission Identification Chart by Year and RPO Code
The fastest way to identify a Chevy Silverado transmission is the RPO code on its build label: M30 is a 4L60E, MYC a 6L80, M5U or MQE an 8-speed 8L90, and MQB or MQC a 10-speed.
Older trucks keep that label in the glovebox, while newer trucks put it on the driver door jamb as a scannable code. The full code list, including heavy duty units, is in the chart below.
If you cannot read the label, the model year, engine and transmission pan bolt count narrow it down quickly. This chart covers Silverado 1500 trucks from 1999 to 2026, with notes on heavy duty trucks where they share a transmission.
Chevy Silverado Transmission Identification Chart With 9 RPO Codes
| RPO code | Transmission | Speeds | Common Silverado use |
|---|---|---|---|
| M30 | 4L60E | 4 | 1999 to 2013 light duty, 4.3L, 4.8L and many 5.3L trucks |
| M32 | 4L65E | 4 | Higher output 1500 trucks in the 2000s |
| MT1 | 4L80E | 4 | Heavy duty gas trucks through the 2000s |
| MYC | 6L80 | 6 | 2007 to 2021 1500, including 2019 to 2021 4.3L and L82 5.3L |
| MYD | 6L90 | 6 | Heavy duty gas trucks from about 2007 |
| M5U or M5X | 8L90 | 8 | 2015 to 2018 1500 with 6.2L, plus some 5.3L |
| MQE | 8-speed automatic | 8 | 2019 and later 1500 with the L84 5.3L |
| MQB | 10L80 | 10 | 2019 and later 6.2L, plus later 5.3L and 3.0L Duramax trucks |
| MQC | 10-speed with electronic range selector | 10 | Later 1500 trucks with the electronic shifter |
Codes can vary between model years and sometimes between Chevrolet and GMC builds. Always confirm with your own truck’s label or a dealer VIN lookup before ordering a transmission or valve body.
Silverado Transmission RPO Quick Reference
Glovebox or door jamb labelM32 = 4L65E. Codes can vary by year and build. Confirm with your truck’s own label before ordering parts.
Where to Find the RPO Code on 2 Silverado Label Types
RPO stands for Regular Production Option. Every factory option on a GM truck, from the engine to the axle ratio, has a three-character RPO code.
Glovebox Label on Older Trucks
On most trucks built before about 2018, GM printed the full RPO list on a Service Parts Identification sticker, usually on the inside of the glovebox door. Look for a code starting with M in the transmission range listed above.
Door Jamb Label on Newer Trucks
Starting around 2018 to 2021, GM moved the label to the lower driver door jamb. The codes are now stored in a two-dimensional data-matrix code, which most smartphone camera apps can read and turn into a text list.
A full list of 2023 Silverado RPO codes published by GM-Trucks.com shows MQB and MQC as 10-speed automatics and MQE as an 8-speed automatic. That list matches what owners see when they scan the door code.
Silverado 1500 Transmissions Across 5 Generations
Each Silverado generation added gears. The table below shows what you will most often find, but engine choice changes the answer inside each generation.
| Model years | Generation | Transmissions offered |
|---|---|---|
| 1999 to 2006 | GMT800 | 4L60E, 4L65E |
| 2007 to 2013 | GMT900 | 4L60E, 6L80 |
| 2014 to 2018 | K2XX | 6L80, 8L90 |
| 2019 to 2026 | T1 | 6L80 (to 2021), 8-speed, 10L80 |
| 2027 and later | Next generation | 10-speed automatic only |
The 8L90 arrived for the 2015 model year, and at first only on Silverado and Sierra 1500 trucks with the 6.2L V8.
For 2027, the redesigned Silverado 1500 drops the 6-speed and 8-speed entirely. In its 2027 Silverado announcement, GM said the updated 2.7L TurboMax is now paired with a 10-speed transmission, and launch coverage reports that the new 5.7L and 6.6L V8s and the 3.0L Duramax also use a 10-speed.
2007 to 2013 Pairings by Engine
In the GMT900 trucks, smaller engines generally stayed with the 4L60E, and many 5.3L trucks used it as well. The 6-speed 6L80 arrived on more 1500 trucks for 2009, when Chevrolet added it alongside the new 6.2L V8.
By 2013, more 5.3L trucks had moved to the 6L80, so a 2009 to 2013 5.3L truck can have either transmission.
2014 to 2018 Pairings by Engine
In the K2XX trucks, the 4.3L and most 5.3L trucks used the 6L80 with RPO MYC. The 6.2L moved to the 8L90 for 2015, and some higher trim 5.3L trucks also received the 8-speed later in the generation.
Go-Parts, which sells these units, warns that the 6L80 for 4WD trucks uses a different output shaft and tailhousing than the 2WD version.
2019 Silverado 1500 Engine and Transmission Pairings for 4 Engines
The redesigned 2019 Silverado offered three automatic transmissions at once, which is why many owners are unsure what they have. GM’s own TechLink service bulletin for the 2019 launch lists the pairings.
| Engine (RPO) | Typical trims | Transmission (RPO) |
|---|---|---|
| 4.3L V6 (LV3) | WT, Custom, Custom Trail Boss | 6L80 6-speed (MYC) |
| 5.3L V8 (L82) | WT, Custom, Custom Trail Boss | 6L80 6-speed (MYC) |
| 5.3L V8 (L84) | LT, RST, LT Trail Boss, LTZ, High Country | 8-speed (MQE) |
| 6.2L V8 (L87) | LTZ, High Country | 10L80 10-speed (MQB) |
The same bulletin notes that each transmission uses a different fluid. The 6L80 takes DEXRON-VI, the 8-speed takes DEXRON-HP, and the 10L80 takes DEXRON ULV. Using the wrong fluid can cause shift problems, so confirm the transmission before a fluid change.
Two more engines joined this generation after launch. The 2.7L turbo four-cylinder, added later in the 2019 model year, used an 8-speed automatic, and the 3.0L Duramax diesel arrived for 2020 with a 10-speed.
Later model years shifted these pairings. The 6L80 left the 1500 after 2021, and more 5.3L trucks moved to the 10-speed in later years. The 3.0L Duramax diesel uses the 10L80 from 2020.
Identify a Silverado Transmission by Pan Bolt Count for 5 Units
If the label is missing or unreadable, the transmission pan is the next best clue. Count the bolts that hold the pan to the case, and note its shape.
| Transmission | Pan bolts | Pan shape |
|---|---|---|
| 4L60E and 4L65E | 16 | Rectangular |
| 4L80E | 17 | Larger, oval-style |
| 6L80 and 6L90 | 18 | Rectangular, ribbed |
| Allison 1000 | 12 | Deep pan |
| 8L90 and 10L80 | Not a practical ID | Use the RPO code |
Transmission builder Gearstar notes that the 6L80 family’s 18-bolt pan has the highest count among common GM automatics, which makes the gasket a fast way to tell it apart from older units. The 4L60E and 4L65E share the same pan, so bolt count cannot separate those two.
Telling a 6L80 From a 6L90
Both use 18-bolt pans, so the pan alone will not separate them. The RPO code is the reliable check, MYC for the 6L80 and MYD for the 6L90. The 6L90 is the heavy duty version and is about 1 3/8 inches longer.
Why the 8-Speed and 10-Speed Need the Label
The newer 8-speed and 10-speed units are packaged tightly with the chassis and wiring, so visual identification is unreliable. Some rebuilder guides also specify grade 10.9 pan bolts for the 8L90, so reuse or replace them with the correct grade.
2 Older Silverado Manual Transmission Codes
Early GMT800 Silverado trucks also offered a 5-speed manual, and those use their own RPO codes. The PerformanceTrucks.net forum lists MG5 for the wide ratio NV3500 and M50 for the close ratio NV3500.
If your glovebox label shows one of these codes, the pan bolt and automatic transmission charts above do not apply. A manual gearbox has no fluid pan, so identification relies on the label, the shifter and the clutch pedal.
Gear Ratios for 4 Silverado Transmission Families
Gear ratios show how each generation improved launch and highway cruising. These figures come from Chevrolet Performance transmission specifications and GM’s published 8-speed and 10-speed ratios.
| Gear | 4L60E family (4L70E spec) | 6L80 | 8L90 | 10L80 |
|---|---|---|---|---|
| 1st | 3.06 | 4.02 | 4.56 | 4.70 |
| 2nd | 1.62 | 2.36 | 2.97 | 2.99 |
| 3rd | 1.00 | 1.53 | 2.08 | 2.15 |
| 4th | 0.70 | 1.15 | 1.69 | 1.80 |
| 5th | None | 0.85 | 1.27 | 1.52 |
| 6th | None | 0.67 | 1.00 | 1.28 |
| 7th | None | None | 0.85 | 1.00 |
| 8th | None | None | 0.65 | 0.85 |
| 9th | None | None | None | 0.69 |
| 10th | None | None | None | 0.64 |
Each step deepened first gear and lowered top gear. That is why a 10-speed truck launches harder with a trailer yet cruises at lower engine speed than a 4-speed truck on the same axle ratio.
The 8L90 and the 10L80 share similar first and second gear ratios, but the 10-speed splits the middle gears more finely. In practice that means smaller rpm drops between shifts, which owners notice most when towing up long grades.
Ratios also help with identification. If you can log engine speed and road speed in each gear with a scan tool, the ratio pattern points to the transmission family.
Known Issues by Transmission for 4 Families
Knowing your transmission also tells you what to watch for. These are the problems most often reported by rebuilders and owners for each family.
- 4L60E: Sun shell failure, burned 3-4 clutches and torque converter slip are the classic failures on older trucks.
- 6L80: Torque converter shudder, failures of the transmission control module, and overheating while towing.
- 8L90 and 8-speed: Harsh or erratic shifts and shudder. The Speerly v. General Motors lawsuit concerned alleged defects in 8L45 and 8L90 transmissions in certain 2015 to 2019 GM vehicles.
- 10-speed: GM recalled 2020 to 2022 Silverado 1500 trucks with the 3.0L Duramax, along with Duramax heavy duty trucks, because transmission control valve wear could lock the rear wheels. Gas trucks used a different transmission and were not included.
For engine-side context on these trucks, our Chevy Silverado years to avoid guide explains which model years drew the most complaints. Before buying a used truck, check the VIN on the NHTSA recall lookup for open transmission recalls.
4 Steps After You Identify Your Silverado Transmission
- Write down the RPO code and drivetrain. A 2WD and 4WD version of the same transmission often use different output shafts and housings, so a used unit must match both.
- Confirm the fluid. Match the DEXRON specification to your transmission and model year before a fluid change. Mixing fluids between the 6L80, 8-speed and 10-speed families can cause shift problems.
- Check for updates. Ask a dealer whether software updates, service bulletins or recalls apply to your VIN. GM has issued recalls and service procedures for some 8-speed and 10-speed concerns.
- Order parts by RPO, not by year alone. Filters, pans, valve bodies and complete units differ between families even inside one model year.
Rebuilders and used parts sellers almost always ask for the VIN for this reason. The same model year Silverado can carry three different automatic transmissions depending on engine and trim.
Silverado Heavy Duty Transmissions in 3 Common Pairings
Heavy duty Silverado trucks use stronger units than the 1500. The pan and RPO checks above still apply.
- Gas HD trucks: The 4L80E (MT1) served older trucks, and the 6L90 (MYD) became the main gas HD automatic from about 2007.
- Duramax diesel HD trucks: The Allison 1000 six-speed was the long-running pairing, identified by its 12-bolt deep pan.
- 2020 and later Duramax HD trucks: The Allison-branded 10L1000 ten-speed is the heavy duty sibling of the 10L80.
If you need gear and axle data for an HD truck, our Silverado gear ratio chart pairs axle codes with model years.
Chevy Silverado Transmission FAQ in 7 Quick Answers
How Do I Know if My Silverado Has a 6-Speed or 8-Speed?
Read the RPO code. MYC means the 6L80 6-speed, while M5U, M5X or MQE means an 8-speed. On 2019 trucks, the L84 5.3L used the 8-speed and the L82 5.3L used the 6-speed.
Can I Tell the Transmission From the VIN?
The VIN identifies the engine but not always the transmission. A dealer or GM parts lookup can pull the full build sheet, including the transmission RPO, from the VIN.
Is the 6L80 the Same as the 6L80E?
Yes. Both names refer to the same 6-speed automatic with RPO code MYC.
Which Silverado 1500 Has the 10-Speed?
From 2019, trucks with the 6.2L V8 used the 10L80, and the 3.0L Duramax used a 10-speed from 2020. For 2027, every Silverado 1500 engine uses a 10-speed automatic.
What Transmission Is in a 2014 Silverado 5.3L?
Most 2014 Silverado 1500 trucks with the 5.3L use the 6L80 6-speed with RPO MYC. Confirm with your label, since later K2XX trucks added 8-speed options.
Does 4WD Change the Transmission?
The transmission family stays the same, but 4WD versions use a different output shaft and tailhousing to mate with the transfer case. A 2WD unit will not bolt into a 4WD truck without changes.
Do All Silverado Transmissions Use the Same Fluid?
No. GM specifies DEXRON-VI for the 6L80, DEXRON-HP for the 8-speed and DEXRON ULV for the 10L80 in 2019 trucks.
