I have always said that if the vehicle hasn't beena a money pit and mechanically and physically is sound otherwise then a transmission should be replaced if needed. That being said, have you gotten any other opinions on whether the trans. really needs replacement or can it be rebuilt? Some shops will just say - "Yup, new transmission" and don't explore the options with the customer, rebuilt, used , etc. Make sure you are explained why they ant to put a new transmission in. Sometimes it is valid, others not so much.
Follow the recommendation in your owner's manual. Or change it every 36,000 miles unless it is a sealed for life transmission.
recommended at 100,000 miles. mine had 88,000 miles and i changed them but they were in great shape.
If it has not been abused and had regular maintenance it can last 200-300 miles. Without maintenance and abuse they can last 35000 miles.
Value of a 2003 Trailblazer w130,000 miles
The transmission may need to be rebuilt. If it is automatic you can try dropping the transmission oil pan and replacing the filter and fluid.
I have had to replace my 2002 Mazda Tribute Transmission at around 150,000 miles. I am not sure if this is normal, and all of my miles were mostly highway. I replaced it with a rebuild and it cost me around 3600 dollars.
You can follow the manual or do it every two years or 24,000 miles. www.trailvoy.com All the answers for your Trailblazer from true enthusiasts.
Volvo says that their automatic transmission has a lifetime fluid that does not need to be changed. On the other hand, most experts recommend replacing the transmission fluid every 30,000 miles to extend transmission life and prevent premature transmission failure.
400 miles
My 02 Trailblazer has 184,000 mile on the original motor. Does not leak or burn oil.
I'm no mechanic but a well known transmission told me that if a vehicle had 80,000 miles on it, the fluid shouldn't be changed and he said that was because if you did it could stir up shavings and actually cause the transmission to go bad but use this info at your on digression.
It could be the pressure control solenoid inside your transmission. Try replacing the transmission fluid and filter first to see if that resolves your issue.