transmission failed - 911

[Humdong]

Wife was driving along up a hill at 25mph and the engine began to rev. The transmission will not engage. Engine idles fine but it will not go into any gear - engine just revs. She says she did not hear any unusual noises when it happened. The code reader did not detect any codes. Fluid appears to be fuller than normal - I think. We have not had this very long but I think I had checked the tranny fluid at purchase and it was normal. I have checked all the related fuses I can find. The previous owner had a magnacharger put on and also supposedly beefed up the transmission and put in a shift kit to handle the additional power. I do think it was somewhat abused by the previous owner but the transmission has never acted up in the 3000 miles we have driven. Vehicle is not under warranty and was 37k miles. Ideas? Is the tranny fried or could it be some electronic issue. What should I check? Any help is greatly appreciated? Thanks.