You save on gas by doing it but defenitely wear and tear on transmission.
nothing
If it has a manual transmission, you simply put it into neutral. If it has an automatic transmission, you would need to remove the driveshaft during towing.
would an automatic transmission car jerk when shifting after having had a transmission flush
That would be a version of the A4LD automatic transmission
You would need to take the shift cable off at the transmission and move the lever manually.
Transmission in Park, Transfer case in neutral.
If it's a 4x4 with a manual transfer case, you can do this by putting the transfer case in neutral. If it has a manual transmission (either 2x4 or 4x4), you can do this by putting the transmission in neutral. If it's an automatic and it doesn't have a manual transfer case, you would have to remove the driveshaft(s).
That is exactly how you would tow it on all 4's.
That would be a 4L80E automatic transmission.
The transmission fluid capacity for your truck, automatic transmission would be 3 quarts.
That would be a 4L60E Transmission.
Yes it can be done, but there is really no point as it is a big job and will cost more than its worth. Plus a manual transmission is way better than a automatic. If you would rather have a automatic transmission it would be wise to just sell the vehicle that has the manual and buy a vehicle equipped with an automatic.