Transmission slips on all gears on 2000 Chevrolet Express 1500

transmision is sliping, it can only speed to 45mph on all gears.

2 answers
Time to buy another transmission, either a used one or a rebuilt one.
fluid full???check engine light on??? we can give free estimate stacks auto call us and bring car in we can check it ,stacks auto 631-422-4010