Today I installed a trans cooler in preparation of my new stall converter. I'm now experiencing a bog or loss of power from the 2nd to 3rd shift. It happens under WOT. It will rev up and take off from a stand still and feels great, hit 2nd gear still feels good then bogs down for a couple of seconds then springs to life again once it's in third. I did not add additional fluid. Could that be the problem?

 

Depending on the size of the cooler, lack of fluid could be your problem.
You might as well try adding fluid 'til it's full again and see if that works. Otherwise, I can't see how adding a cooler could decrease the quality of shifts??

 

If you were a little low before the cooler, then that's the problem. Friend had the same problem. Usually have to be about a quart low before you notice any symptoms

 

You added capacity to the system. Adding more fluid should have been next.

 

Half a quart of fluid and all is good again. I get in such a hurry sometimes that I forget the simple stuff.