2003 Chevy Trailblazer Transmission

The 2003 Chevy Trailblazer was built on the same platform as the Colorado and GMC Canyon twins.  They were both rear wheel drive and used the same drivetrain components (for the most part).  Trailblazers used the 4L60e across the board regardless of which engine was in front of it.  But, these particular versions of the 4L60E use a different bell housing than the LS engines.  This means you need to be really careful when you’re looking for a replacement transmission, because they’re not easily swapped for one another.

The later 4L60E transmissions use a two piece bell housing, which means that you can swap the bell housings out.  The Trailblazer came from the factory with Dex III transmission fluid.  General Motors suggests that you replace it with Dex VI.  The “drain and refill” transmission fluid capacity is 5.0L.

2003 Trailblazer Transmission

Common Trailblazer Transmission Problems

By 2003 the 4L60e had a decade of refinement to it, which made the transmission one of the most reliable things on the vehicle.  In fact, there were so many issues with the L6 engines that were put in these vehicles that the engine would almost always give out before the transmission.  I don’t really have any statistics to back that one up, but I have seen plenty of real life examples of that exact scenario.  If you’re one of the few people lucky enough to have a v8 version of the Trailblazer you’re

If you’re reading this at the time it was written, the 2003 Chevy trailblazer is 15 years old. That means that there has been a lot of time for parts to degrade.  Fifteen years is a lot of time for a wiring to go bad, harnesses to come loose, or not have any maintenance done.

Here’s more on 4l60e problems.

Bad Fluid

When you’re looking for a transmission problem in an older vehicle a good place to start is to take a look at the transmission fluid.  Does it smell burnt? What color is it?  It can tell you a lot about the condition of the transmission.

If your Trailblazer has it’s original transmission it may have never been changed at all.  Transmission fluid is one of the most neglected pieces of automotive maintenance.


Limp Mode

When it comes to entering limp mode, these transmissions are notoriously fickle. The transmission enters limp mode because their is some sort of electronic sensor that is giving it a signal that is out of it’s normal operating range, usually one of the shift solenoids.

Here’s much more on limp mode.


Swap Compatibility

If you choose to replace the transmission yourself you need to be really sure that you are getting another 4L60E that is compatible with the one that you are pulling from your Trailblazer.  Certainly a 4L60E from the 90’s is not going to match up.

You’ll need to find a transmission from an L6 GMC Envoy or Trailblazer, if that is the engine you have.  If you have a V8, your options are wide open.  Just make sure that you are checking that they are compatible.  Here are a few good resources for that:




How much should a rebuild cost?

The 4L60e has been around for very long time, and is one of the most mass-produce transmissions ever made. That’s good news for you, because that means that there’s plenty of replacement parts available, and they’re relatively cheap.

Also, another thing that you have going for you is that The 03′ Trailblazer is rear wheel drive, which means that pulling the transmission is relatively easy to do.  This will keep your labor cost down quite a bit compared to working on a front wheel drive vehicle.

If you are looking to take an 03′ Trailblazer in to have the transmission rebuilt and replaced, $2000 is a pretty good price.



While the 4L60E that comes in the Chevy Trailblazer ( and GMC Envoy) is incredibly durable, they can go bad.  If they do go bad it’s important to replace it with a similar transmission.  There are many compatibility issues.  If you do your due diligence, you will have your 03′ Trailblazer back on the road in no time.

Further Reading:

2004 Trailblazer Transmission