How do I tell which Chevy transmission I have?

Check the identification tag on the transmission or decode your vehicle’s VIN/build sheet to identify the exact transmission model. In most Chevy vehicles, a tag or stamped code on the case reveals the transmission family (4-, 6-, 8-, or 10-speed) or indicates a particular manual unit, and the VIN can be used with GM’s decoder or a dealer to confirm the original specification.

Where to look on the transmission

Use the following steps to locate the identifying information directly on the unit. Each Chevrolet model may place tags or stamps in slightly different spots, but these locations are the most common starting points.

• Identification tag: Many GM automatics have a small metal tag affixed to the side of the case near the top or toward the rear of the transmission. The tag typically lists a model code, series, and a date.


• Case stamping: Some transmissions carry a stamped code directly into the aluminum housing or on a plate that sits over the bolt area. This code is usually a short alpha-numeric sequence that corresponds to a specific transmission family.


• Bellhousing and mounting pattern: The shape and bolt pattern of the bellhousing can hint at the family (for example, different patterns separate older 4-speed automatics from newer 6-, 8-, or 10-speed units).


• Shifter and linkage cues: The number of forward gears you can feel or see in the shift pattern can indicate the general family (4-, 6-, 8-, or 10-speed), though this is less precise without confirming the exact code.


• Auxiliary identifiers: Some vehicles carry a secondary tag or marking on the transmission cooler lines or near the pan that references the model family or part number.

Concluding: Reading the tag or stamped code on the transmission and comparing it to GM’s published identifiers is the most reliable on-vehicle method. If the tag is unreadable, move to VIN-based verification.

Decode using the VIN and build data

If you can’t read the tag or you want to confirm with official records, use the vehicle’s VIN and build data. This will tell you what transmission your car was originally equipped with and, in many cases, what it currently has if the original hasn't been swapped.

1. Locate the VIN: It’s on the driver-side dash near the windshield, the driver’s door jamb, and on the title and registration documents.


2. Use GM’s VIN decoder or contact a GM dealer: Enter the VIN to retrieve the original transmission code or option list for your specific model and year. This will typically identify the transmission family (for example, a 4L60-E, 6L80, 8L90, or 10L80, depending on the generation and model).


3. Cross-check with the window sticker or build sheet: If you have access to the original window sticker or the vehicle’s build sheet, look for an RPO (regular production option) code that corresponds to the transmission. A dealer can translate this code for you if needed.


4. Verify against service history: If you’ve had the transmission replaced or swapped, compare the documented part numbers or codes in service records to confirm whether the current unit matches the vehicle’s original specification or whether a swap occurred.

Concluding: VIN decoding and build data provide an authoritative cross-check. When tags are compromised or missing, this method is often the most reliable way to confirm your transmission’s identity.

Manual vs. automatic: what you’re looking for

Chevrolet has used a variety of manual and automatic transmissions across generations. Knowing whether you have a manual or automatic helps narrow down the possibilities before you read tags or decode the VIN.

• Automatic transmissions: Look for a model name such as 4L60-E, 6L80, 8L90, or 10L80 in the transmission’s official markings or in the VIN/build data. Modern GM automatics are typically 6-, 8-, or 10-speed.


• Manual transmissions: If your car has a manual gearbox, you’ll often see a model stamp (for example, TR6060 in some Camaros and Corvettes, or earlier Muncie/M20/M21 series in older Chevys) on the case or near the shifter linkage.

Concluding: Distinguishing automatic from manual early helps you choose the correct identification path—tag/stamp reading for automatics, and manual model stamping for older manuals.

Common clues and what they mean

These general indicators can help you categorize the transmission family, though they should be verified with a tag, stamping, or VIN data for certainty.

• Gear count: 4-, 5-, 6-, 8-, and 10-speed configurations map to distinct transmission families used by different Chevy models and generations.


• Electrical controls: Many newer automatics use electronic control modules and a modular valve body; the presence of such controls often points to later-generation GM automatics (6L80/8L90/10L80 families).


• Cross-reference with vehicle type: Trucks, SUVs, and performance cars may share families (for example, 6L or 8L series) but differ by tune and hardware.

Concluding: While these cues help narrow down the possibilities, the tag, stamping, or VIN-based verification remains the definitive approach.

When in doubt, get expert help

If you’re unsure after checking for tags, stamps, and VIN data, consult a Chevrolet dealer or a qualified shop. Have your VIN and vehicle details ready so they can pull the exact original specification and confirm whether a swap was performed.

Summary

To determine which Chevy transmission you have, start with the transmission’s identification tag or stamped code on the case, which usually identifies the exact model family. If tag information isn’t legible, use the VIN and build data to pull the official transmission specification from GM’s decoder or via a dealer, then cross-check with the window sticker or service history. Distinguishing between manual and automatic units and noting the number of gears helps narrow down the possibilities before you confirm with official records. Accurate identification supports correct maintenance, repairs, and part compatibility.

How do you tell if you have a TH350 or TH400?

You can tell a TH350 from a TH400 by the pan shape, with the TH350 having a square-like pan with a corner cut off, and the TH400 having a unique, more irregular shape with one side straight. Other differences include the kickdown mechanism: TH350s use a cable, while TH400s have an electrical switch and plug on the case. The TH400 is also visually larger and heavier than the TH350.
 
You can watch this video to see a visual comparison of the TH350 and TH400 transmissions: 58sPrecision TransmissionYouTube · Jun 6, 2020
Key differences

• Pan shape:
  • TH350: Square-ish with one corner cut off. 
  • TH400: Irregular shape, with one side straight and a bulge on the other ("elephant ear"). 
• Kickdown mechanism:
  • TH350: Has a mechanical kickdown cable that runs from the carburetor or throttle linkage to the transmission. 
  • TH400: Uses an electrical kickdown with a slide switch and a plug on the side of the case, eliminating the need for a cable. 
• Size and weight:
  • TH350: More compact and lighter. 
  • TH400: Larger, heavier, and visibly more rugged. 
• Strength:
  • TH350: Designed for lighter-duty and moderate-performance applications. 
  • TH400: Built for heavy-duty and high-torque applications. 

How do I know if I have a 4L60E or 700R4?

The easiest way to identify a 700R4 vs. a 4L60E is by looking for an external TV cable on the 700R4 or a large electrical connector and a missing governor cover on the 4L60E. Other key differences include the 4L60E having a separate, removable bellhousing (on later models) and a 17-bolt pan, while the 700R4 has a one-piece case and a 16-bolt pan.
 
This video shows the key differences between the 4L60E and 700R4 transmissions: 49sMonster TransmissionYouTube · Feb 25, 2015
Primary identification methods 
This video explains the evolution of the 700R4 to 4L60E and their key differences: 1mSpeedway MotorsYouTube · May 7, 2025

Feature	700R4	4L60E
Throttle control	Has a physical TV (throttle valve) cable on the driver's side.	No TV cable; controlled electronically.
Electrical connection	No electrical case connector on the driver's side.	Has a large electrical harness connector on the driver's side, near the servo cover.
Governor	Has a governor cover on the rear tail shaft housing.	Does not have a governor cover.
Bellhousing	One-piece case with a fixed bellhousing.	Later models (1996+) have a removable bellhousing.
Oil pan	Has a square-shaped oil pan with 16 bolts.	Has a more rectangular oil pan with 17 bolts.

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How do I tell if my transmission is a 4L60E or 4L80E?

You can tell the difference between a 4L60E and 4L80E by checking the transmission pan shape, which is a reliable visual cue: the 4L60E has a rectangular pan with 16 bolts, while the 4L80E has a larger, more irregular (often described as rectangular with clipped corners) pan with 17 bolts. The 4L80E is also physically larger, heavier, and was used in heavier-duty applications like 2500/3500 series trucks and SUVs.
 
This video explains how to identify a 4L80E and 4L60E based on their physical differences: 1mPSI ConversionYouTube · Dec 8, 2020
Pan shape and bolt count

• 4L60E: Rectangular pan with 16 bolts.
• 4L80E: Irregularly shaped pan (like a rectangle with two clipped corners) with 17 bolts. 

Size and weight

• 4L60E: Lighter and smaller, weighing around 150 lbs.
• 4L80E: Significantly larger and heavier, weighing around 236 lbs. 

Vehicle application

• 4L60E: Used in light-duty applications like 1500 series trucks and SUVs. 
• 4L80E: Heavy-duty transmission used in 2500/3500 series trucks, heavy-duty Suburbans, and vans. 

Will my VIN number tell me what transmission I have?

Yes, you can often tell your transmission type by checking the VIN, but it's not guaranteed because transmission data isn't always encoded in the VIN according to a single standard. To find out for sure, you can use the VIN with an online decoder like the NHTSA VIN decoder, check with a dealership's parts department, or look for physical identifiers on the vehicle itself. 
How to find your transmission using the VIN

• Use an online VIN decoder: Input your 17-character VIN into a decoder, such as the one provided by the National Highway Traffic Safety Administration (NHTSA). Look for a "Transmission" or "Engine" category in the results. This is the most direct way, but it may only provide basic information like "manual" or "automatic". 
• Contact a dealership: Provide the VIN to the parts department of your vehicle's dealership. They can look up your specific vehicle's original factory options and tell you the exact transmission it was built with. 
• Check the vehicle's build sheet or window sticker: If you have them, these documents will list the original factory options for your vehicle, including the transmission type. 
• Use a specialized decoder (if available): For certain vehicle brands, like BMW, there are specialized online resources (e.g., RealOEM) that can provide detailed information by inputting the last seven digits of the VIN. 

If the VIN doesn't provide the answer

• Inspect the physical transmission: Crawl under the vehicle and look for a tag on the transmission itself, which will have a specific model number. You can also get a general idea of the type by looking at the shape of the oil pan or checking online for images of your vehicle's transmission.
• Provide other vehicle information: If the VIN decoder doesn't work, provide your vehicle's make, model, year, and engine size to a knowledgeable person or online forum, and they may be able to determine the correct transmission based on that information.