If you’re asking “S80 Transmission – What Does It Come Off Of?”, you’re likely holding a part, shopping for one, or trying to fix a vehicle. The quick answer is that the S80 transmission is primarily known as the robust automatic gearbox from the legendary GM 4L80-E family. It’s a heavy-duty workhorse found in many full-size trucks and vans from the late 80s onward.
This article will clear up the confusion, tell you exactly which vehicles used this transmission, and explain why it’s so highly regarded. We’ll cover its specs, common problems, and what you need to know if you’re buying or rebuilding one.
S80 Transmission – What Does It Come Off Of
The S80 is a model designation within General Motors’ 4L80-E automatic transmission series. It’s not a standalone model; think of it as a specific version or build. The “S80” code is typically stamped on the transmission’s case or on the vehicle’s service parts identification label. When you see S80, it specifically refers to a 4L80-E transmission built for heavy-duty applications in rear-wheel-drive vehicles.
It’s crucial to understand that the 4L80-E (and thus the S80) is the electronic evolution of the older, mechanical 3-speed Turbo 400 (TH400) with an added overdrive gear. It was designed to handle big engines and heavy loads.
Primary Vehicle Applications: The Main List
So, what vehicles did the S80 transmission actually come in? It was used in a wide range of GM trucks, vans, and even some performance cars from roughly 1991 into the 2000s. Here is a comprehensive list:
* Chevrolet & GMC Trucks/SUVs:
* Chevrolet Silverado 2500/3500 (1991-2002+)
* GMC Sierra 2500/3500 (1991-2002+)
* Chevrolet Suburban 2500 (1991-1999)
* GMC Yukon XL 2500 (1999-2000)
* Chevrolet Tahoe (limited use in 2500 models)
* Chevrolet Avalanche 2500 (2002-2006)
* Hummer H1 (1992-2006)
* Commercial Vans & Chassis:
* Chevrolet Express 2500/3500 (1996-2002+)
* GMC Savana 2500/3500 (1996-2002+)
* Chevrolet Step-Van & P-Series chassis
* Performance & Specialty Vehicles:
* Chevrolet Corvette (1991-1996) – specifically the ZF6 manual was an option, but the auto was the 4L80-E/S80 in some years.
* Chevrolet Camaro (1998 B4C Special Service Package)
* Various motorhome and RV chassis.
The S80 was commonly paired with big-block and high-torque small-block V8 engines, such as:
– The 7.4L (454) Big Block V8
– The 6.5L Detroit Diesel Turbo-Diesel V8
– The 6.0L and other high-output LS-based Vortec V8s in later models
Identifying Your S80 / 4L80-E Transmission
Don’t just assume you have an S80. Here’s how to positively identify it. The easiest way is to locate the metal Service Parts Identification (SPID) tag. This is usually found in the glove box, on the driver’s side door jamb, or under the center console lid in some vans.
1. Find the SPID tag, which is a sticker or metal plate covered in three-character codes.
2. Look for the transmission code. Common codes for the 4L80-E/S80 include:
* MT1 – This is the most common RPO code for the 4L80-E transmission.
* M18 – Another frequent code for the 4L80-E.
* M38 – Also indicates a 4L80-E.
* The letters “S80” may also appear seperately on this tag.
You can also identify it physically. The 4L80-E/S80 has a distinctive shape:
* It’s a long, heavy transmission (about 155 lbs dry).
* It has a deep, finned aluminum pan with a slight rear sump and a unique shape—it’s not perfectly rectangular. The pan has 17 bolts.
* The electronic connector is on the driver’s side, near the rear of the transmission case.
Key Specifications & Strengths
Why is the S80 transmission so sought after? Here are the specs that made it famous:
* Gear Ratios: 1st (2.48), 2nd (1.48), 3rd (1.00), 4th (0.75), Reverse (2.07).
* Torque Capacity: Rated to handle up to 440 lb-ft of torque in stock form, making it vastly stronger than the lighter 4L60-E.
* Construction: It uses a massive 32-spline output shaft and a stout 298mm torque converter. The gear sets and clutch packs are significantly larger than those in half-ton transmissions.
* Electronic Control: The “E” in 4L80-E stands for electronically controlled. It relies on the vehicle’s PCM and a dedicated transmission control module (TCM) in some applications to manage shifting, line pressure, and torque converter lockup.
Common Problems & Issues to Watch For
Even tough transmissions have weak points. Being aware of these can save you time and money.
* Electronic Failures: The most common issues are not mechanical but electrical. Faulty sensors, like the Vehicle Speed Sensor (VSS) or Transmission Fluid Temperature (TFT) sensor, can cause erratic shifting or limp mode.
* Solenoid Pack Issues: The internal wiring harness and shift solenoids can fail, leading to harsh shifts, no shifts, or getting stuck in a single gear.
* 3-4 Clutch Burn-Up: Under high load or if towing without proper cooling, the 3-4 clutch pack can wear prematurely, causing slippage or failure of 4th gear (overdrive).
* Torque Converter Clutch (TCC) Problems: A worn TCC solenoid or valve body issue can cause shuddering during highway cruising or prevent lockup entirely, leading to overheating and reduced fuel economy.
* Input & Output Speed Sensor Correlation Codes: If the PCM sees an illogical difference between input and output shaft speeds, it will set a code and often default to a fail-safe mode.
Rebuild & Upgrade Considerations
If you’re rebuilding an S80 for performance or heavy towing, here are key areas to address:
1. Replace the Solenoid Pack & Internal Harness: Always install a new, high-quality solenoid pack and wiring harness during any rebuild. This solves a huge percentage of potential future problems.
2. Upgrade the 3-4 Clutch Pack: Add extra clutch plates or use high-energy friction materials to handle more power.
3. Install a Superior Valve Body Kit: A shift correction or “transgo” kit can improve shift firmness, line pressure consistency, and overall durability.
4. Choose the Right Torque Converter: Match the converter stall speed to your engine’s powerband and intended use (towing, street performance, etc.).
5. Add an Auxiliary Cooler: This is non-negotiable for towing or high-performance use. It keeps fluid temperatures in a safe range, extending the life of all internal components.
Swapping an S80 into Another Vehicle
The S80/4L80-E is a popular swap transmission due to its strength and electronic controls, which can be managed by standalone controllers. Here’s a basic outline of what’s involved:
* Controller: You will need a standalone transmission control unit (like from US Shift, TCI, or Holley) to manage shift points and TCC lockup.
* Crossmember & Driveshaft: The transmission length and mount location are different from other models. You’ll likely need a custom crossmember and a shortened or lengthened driveshaft.
* Torque Converter: Ensure you have the correct converter for your flexplate. The bolt pattern and hub size must match.
* Wiring & Sensors: You’ll need to integrate the transmission’s input and output speed sensors, solenoid pack connector, and TFT sensor into your new control system.
FAQ: S80 Transmission Questions Answered
Q: Is the S80 the same as a 4L80-E?
A: Essentially, yes. The S80 is a specific model code for a 4L80-E transmission. All S80s are 4L80-Es, but not every 4L80-E may have the S80 code stamped on it, depending on the year and plant it was built in.
Q: What’s the difference between a 4L60-E and a 4L80-E/S80?
A: The 4L80-E is much larger, heavier, and stronger. It’s designed for 3/4-ton and 1-ton applications, while the 4L60-E is for 1/2-ton trucks and cars. The 4L80-E has a significantly higher torque capacity.
Q: Can I put an S80 transmission behind my LS engine?
A: Absolutely. It’s a very common and recommended swap for high-horsepower or towing applications. You will need the correct flexplate/adapter and a standalone controller or a compatible PCM tune.
Q: How much fluid does an S80 transmission hold?
A: Dry fill is approximately 12.5 quarts (about 11.8 liters). A pan drop and filter change usually requires around 5-7 quarts, but always check the dipstick level with the engine running and fluid at operating temperature.
Q: What year did they stop making the S80?
A: The 4L80-E transmission, including S80 models, was produced from 1991 well into the 2010s for various heavy-duty and commercial applications. It began being replaced by the 6L90 in many consumer trucks in the late 2000s, but remains in service.
Q: My S80 is slipping in overdrive, what’s wrong?
A: This is a classic symptom of a worn 3-4 clutch pack. It could be due to normal wear, but is often accelerated by towing without an auxiliary cooler, low fluid, or degraded fluid. A rebuild focusing on that clutch pack is usually needed.
In summary, when you find an S80 transmission, you have a piece of heavy-duty GM engineering history. Knowing it comes from 3/4-ton and 1-ton trucks, vans, and some performance vehicles helps you understand its potential. Whether you’re maintaining the one in your truck, buying a used unit, or planning a swap, its reputation for strength is well-earned. With proper care, identification, and potential upgrades, this transmission can reliably handle massive power and demanding jobs for hundreds of thousands of miles.