Transmission Prob?

Hi,

our sec. Lumina have an problem, at least this says my girlfriend.
When we drive the 1,2 gears are good, I didnt feel anything, but when we drive over 40 km/h the third gear comes and we feel that the third gear comes a little bit hard.

The oil is good, nothing smell burned, is red, and level is on max.

Any Idea?

Ok I will try new Attempt,

the trans shift fine from 1st to 2nd gear, but sometime it shift hard from 2nd to 3rd gear.

And sometimes very rarely the trans slams in P very hard.

Now any ideas? Sorry for bad english, I must write mor in english then it goes better.

First check the Dog Bone mounts on the radiator header, and as well check the front trans mount...