2004 Chevy trailblazer ext v6

Many TB owners think they have a v6, when it's a I6.
Most TB owners I've seen on RV forums, pulling a TT, end up trading for a better tow vehicle.
The short wheelbase doesn't make for a pleasant tow experience.

The door sticker doesn't tell you anything about towing.

In the owner's manual, in the section on towing, is a series of charts for tow capacities. These are based on engine, transmission, body style, trim level, and axle ratio. You need these specifications to figure out the tow rating of your Trailblazer.

Shooting from the hip, you could tow a SMALL travel trailer, at most 4000lbs loaded and ready to camp. One of those 16' or shorter single axle units would work fine. My old V6 1500 pickup had a tow rating of 5000lbs, and that was generous. The limiting factor there was power; you simply could not keep up with traffic towing much.

I had a 2003 TB EXT with I6, 3:42 gears. We need to know a bit more about the truck. EXT or not? Gear ratio, look in the glove box for the RPO sticker. Three axle ratios were offered for the GMT-360/370 platform. The 4:10s in a TB with an I6 is pretty rare.

GU6 = 3:42
GT4 = 3:73
GT5 = 4:10

Once you know this information you can cross reference it in your owners manual in the towing section to find out your max towing capacity.

The I6 is an excellent engine. My max towing capacity was 4099#. I towed a 3500# hybrid trailer with it, once out west in the Rocky mountains. Wonderful towing experience. Later for one season we towed our current Jayco X20E with it. 4750# GVWR. Adequate but not stellar. I would not have towed it in mountains. The TB had 160k on it so it was an easy decision the next season to upgrade to the Sierra in my sig.

That said all GMT-360/370s have the towing package standard. There is a built in transmission cooler that is more than adequate for most towing. I didn't add one until I got the bigger trailer. I would change your transmission fluid and make sure to use DEX VI instead of the factory installed DEX III. Dex VI is a synthetic blend that came out in 2006 and is recommended for older transmissions. It runs cooler and is a better fluid.

Another thing to consider is payload (found on the yellow sticker in the door) and tongue weight. With a WDH the max tongue weight is 920# as I recall.

If you keep the GVWR of the trailer 1000# under the max towing capacity of the TB you'll be fine in all respects. More than that and you'll be disappointed with the towing experience.

The sticker on your door should show axle weight and gross weight ratings, nothing for tow rating. Do you know your axle ratio (3.42, 3.73 or 4.10)?

If I recall, the ratings were 4800#, 5300# and 5800# for the I6. There was no external tranny cooler, so if you push the limits consider getting one and only tow in 3rd.

The I6 had good low end torque, but the HP is made at upper RPMs so you will need to let it rev.

The numbers on your door are generally specific to your truck. The numbers in the book are usually best possible ratings for a properly equipped truck with no extra options.
Post pictures of the stickers & book numbers.
Also, no V6 trailblazer in 2004. Either 4.2 straight 6, or V8

Is it a Blazer or Trailblazer? The Trailblazer never had a V-6. I pulled a small 1795# 17' trailer with my 4.3L Blazer and as long as I stayed out of overdrive it did just fine. The Trailblazer has more power and larger vehicle.