what is it and how do i know it happening?

thanks

Defueling occurs between shifts to save the trans.

so that hesitation during the shift is defueling and it is on pourpose? is there a fix for this after i go throught the trans

The only fix that I know of is a PPE Programmer for the LBZ. There is a thread on it. You may be able to find it using the search.

PPE hot + 2 et does remove defuel on levels 3 - 7. The shifts are so much better, this is what it should be from g.m.