Need help will 03 corvette c5 4l60e transmission fit in my 03 chevy silverado or wat will I need to do to make it fit its a 300mm same as the c5

 

Sorry, no.

This is what a 2003 Silverado 4L60E transmission looks like:

Standard type Bell-Housing, and an Output-Shaft that will either fit a Transfer-Case or fit a Tail-Housing.


This is what a 2003 Corvette 4L60E transmission looks like:



The Bell-Housing ONLY fits a 6-Foot long "Torque-Tube", which the other end of attaches to the rear of the engine (there are no Drive-Shafts used).
Torque-Tube:



The Output-Shaft ONLY fits into that Differential (making the assembly essentially a "Trans-Axle" instead of a Transmission with a separate Rear-Differential).

If absolutely necessary... the Corvette 4L60E could have the Output-Shaft swapped with the Silverado Output-Shaft.
However this process requires complete disassembly of the Transmission, along with other necessary parts (Bell-Housing, ETC...) from the Silverado Transmission to be swapped.

The 4L60E is the most common and the most produced Electronic Longitudinal 4-Speed Automatic Over-Drive transmission in the world.
Just find another 4L60E from another truck like yours... there are TONS of them around.

If your Silverado is Four Wheel Drive... then you can not use a transmission from a Two Wheel Drive vehicle.
Any 2001 through 2005 Chevrolet or GMC SUV or Pick-Up transmission should work.