Transmission Failure

Hey!
My wife broke down yesterday, we have a 97 venture with a recently replaced tranny and engine so thought it was a good deal to buy it. But about a week ago check engine light came on took it to a Auto store and they checked the code "P1870 internal transmission part slipping" well he cleared the code and it dissapeared until yesterday it came on and car was just revving like it was in neutral and my wife pulled over we tried multiple times to put in gear but it just shakes. If we turn the car off and let it sit for 10 sec. we can start it up and take of up to 10-15 mph and then same problem again and the problem is the same in all positions R,D,3,2,1 After starting it we can even "burn rubber" so to me that dont seem to be a slippage because then it wont be able to give that much power to the wheels a electronic problem maybe?

I was told by a friend, to check so the TCS is working properly. So how would i do that any suggestions besides turning it off at the dash???

Is there any way to bypass it if that would be the problem??