Low fluid. They say it is a sealed system but in fact it is not. Your fill hole is a red cap under the air intake box on the top of the transmission. You are to be able to see fluid when you remove the cap. DON'T OVER FILL!!!!. I just added some and still didn't see it but it worked fine after addingsome. Careful do not over fill !!!!
the transmission could be going out or slipping or your transmission fluid could be low
my son bought a 1996 cougar that felt like the transmition was slipping and we had the transmission flushed and it fixed it.
It could. When overfull the fluid can aerate, which will cause slipping and a loss of lubrication.
It could be a bad clutch.
Yes, it could. If the fluid contacts the spinning parts of the transmission, it could aerate. Air in the fluid will cause slipping and eventual failure.
Could be transmission bands are worn and require adjustment or replacement Try changing transmission fluid and filter
It probally is the transmission or your brakes could be slipping.
Whatever you do, do not use "Stop Slip" Additives. These thick and syrupy additives will gum up the filter, cause fluid starvation and hurt the transmission worse. If the transmission is slipping, It can be due to several things. The most common, is the Torque Converter, it can fail and cause the transmission to slip consistently. Next could be the seals on the Transmission engagement piston (found in AX4S transmissions) the seals tend to go bad causing the transmission to lose pressure during shifting and actuation causing the vehicle to slip into gear. In extreme cases, the piston itself maybe cracked. Another possibility is faulty solenoids. Solenoids that do not engage quickly and securely can cause slipping, particularly with those that manage pressure in the transmission. If only one gear is slipping, this is probably your culprit. And finally, another common cause of slipping is worn or loose clutch bands inside the transmission. These aren't like a regular clutch in a manual vehicle, and require knowledge to replace and tune. If in doubt, take it to a trusted mechanic.
If its slipping only in 4th gear, it could be that your releaser bearing is gone with the p/plate. Or your gearbox has had its days and would need to be replaced/ repaired.
The Trailblazers transmission could be slipping, or the engine could be idling too low to spin the transmission fast enough to combat the gravity of the hill. Either of these could cause the roll back issue.
A slipping clutch.
If your transmission is slipping when it is hot that could be a sign that you do not have adequate pressure in the transmission line. It could be because of wear, it's in need of service, or that it's low on fluid.