Chevy trailblazer transmission

Sounds like it's time for a new transmission. A common failure point on these. Jim

I agree with the failing transmission. But if you want to try something then service it and add in 1 quart of TransX during the refill. Then carefully drive it around for 20 minutes then park it and let it sit for a few days. Then drive it and see if it helps. If it does then you bought yourself a little more time but eventually it will need overhauled.

I'm an old hotrodder from the 60s & 70s, and I've had a lot of experience with auto transmissions... Yes, you need a transmission rebuild at least. And additives, I've known people who get bad transmissions running well just to sell a car to people who don't know they've been swindled. If you've never used trans additives, there are lots of them that will work for a while. TransX is popular with big truckers. Others that should work for you, if your problem isn't destroyed seals are, Whatever It Takes, Hot Shot, Lubegard, and BG's AT+. But all-in-all, the eventual cost of trans repair will likely eat up half the value of your truck.