Has no reverse in my 1997 Saturn SL2 4cyl?

Do you have any codes?How does it drive in the forward gears?To completely loose reverse you have too low of pressure in the transmission a leaking 2nd gear clutch piston a loose input shaft nut or a bad reverse servo piston. Most likely you have a loose input shaft nut or too low of pressure in the transmission. You would have to get a transmission pressure test gauge kit to test the pressure and go from there. It's most likely a on car repair Most places if you take it to get it repaired will tell you you need to replace the transmission or rebuild it. But most of the time they are wrong and just don't diagnose the problem correctly.