Hi all i have a 2007 hummer h3 78k miles and i have slipping when shifting under heavy acceleration(just to clarify when accelerating it does not slip until it tries to shift) and it seems like it shifts into drive and lock out to quickly causing it to constantly jump in and out of lockout. Fluid are clean and do not smell burnt. Per recommendation i have replace the Maf sensor and that did not change anything. Any input would be great.

 

Have you ever changed the transmission fluid and filter? Your miles are fairly low, but the truck is 12 years old and that fluid/filter may be tired.

A stock I5 H3 will shift in and out of full lock up often depending upon speed and load, more so on windy days and hills at highway speed.

 

Like Doc said, definitely drop the pan clean it out, new filter and fresh DexVI, before you destroy that trans. GL