Also, I noticed that before it broke the pump both times it began shift shift really hard from 1st to 2nd gear. All others were normal. Now that I have my 3rd new pump, new filter, new gaskets, torque convertor....trans is back together and working fine. UNTIL today....started shifting hard again. Now I'm affraid to go very far from the shop. I'm going to check the trans fuse, but we couldn't find anything else that looked bad or wrong. My dad has been a 4x4 mechanic for over 35yrs...but he refuses to work on auto's, now I know why. He has a friend that owns a transmission shop and has gotten some tips from him, but even they didn't know what might be wrong. They also know the 4L60E inside and out. Guess I need to find someone with a tech 2 scanner? This thing is starting to really **** me off, needs to be fixed, and then SOLD

 

Your TPS sensor can cause harsh shifts if its output is erratic.

With a quick failure of the pump, I would question the source (manufacturer). Is the 3rd pump from the same place?

If it happens again, you should check to make sure that everything associated with the pump is proper (flatness, perpendicularity, etc). You may have somehow damaged the pump cover. That is unless you are replacing the entire pump cover.

But another thought popped into my head. Where did the replacement transmission come from? What was it out of? Did the pump cover have 'PWM' in raised lettering on it?