I have a 2013 Silverado 2500 with 150000 miles, about 5 miles after an oil change I noticed two hard shifts.
The next day I drove 1/2 mile, the trans slipped and is now disabled.
I had mechanic look at it and suggested it might be engine oil in the transmission. They suggested I drain the transmission fluid and change filter. Less than 10 miles since oil changed mechanics said that the oil looked brown not red, which is consistent with transmission fluid. They suggested it may be engine oil.
What is your opinion ? Is there a recourse?