Today when driving on the highway in the Uplander (2005 Chevy Uplander 3.5 V6) The trans would clunk then shoot the RPM up to around 3500, it feels as if it just drops out of over drive for no reason, then after this happens, you let off the gas and the engine revs down to 1000 RPM. Its odd, after driving for a mile or so of 3500 RPM at 70 MPG the TC will lock back up, but almost partially it seems like. About 5 miles later the same thing happens again. I get a clunk and the RPMs shoot up to around 3500 RPM. Here is a pic of me cruising at 70 after the clunk, and I let my foot all the way off the gas, it sits at 1000 rpm.... **NOTICE, the trans IS in drive, not neutral. To get any power you have to step on the gas and it just revs to 3500 RPM where the trans catches (assuming 4th gear) and will start to pull the van. Again, after a mile or so of this the TC will decide to lock up a little. NOTE: this is on our rebuilt transmission going on 2 years. What could the problem be?