slipping auto transmission?

[yaris05]

hey guys

i have a 2005 yaris (99100kms). Sometimes when im driving it seems like my transmission slips into gear (it only does it once) then it just drives normally.

could this be a major problem?

[CTScott]

When you say it slips into gear, when it does it does it rev higher than you'd expect it to as it is moving between gears?

With my experience with owning almost exclusively automatics over the past 30 years, once you start noticing an issue with an automatic it is typically too late. If it is doing what is called "flaring", you can try changing the AT fluid, but it is more likely a an issue with wear, which changing the fluid won't fix.