2001 Saturn SL2 1.9 DOHC - Hesitates when accelerating and downshifts into gear hard.

First of all thank you so much for your donation. The code po733 is for incorrect 3rd gear ratio. Code p0734 is for incorrect 4th gear ratio. Code p0326 is for your knock sensor that could be caused by excessive engine noise or the knock sensor or circuit itself. Code P0184 I can't find if you could check your code number's again and make sure what that last code was we can go from there. The code's I would start with first would be the P0733 and P0734 there usually caused be a transmission line pressure issue in the transmission and sometimes a leaking clutch piston and a actuator or electrical problem. The first thing we need to check when the transmission fluid is hot is the high and low line pressure you will need a transmission fluid pressure gauge kit. Also iam warning you now to properly diagnose this problem it requires a scan tool that can buzz the transmission actuator's and you will have to remove the valve body at some point and air check the clutch pack's with compressed air. Do you have a delay in reverse?

You could try to tackle the other code's yourself but the transmission ones that's going to take a lot of special expensive tool's plus some skill and knowledge of transmission's like air checking the clutches and doing the pressure test's etc. On that model car if you have a delay bang into reverse I would have the input shaft nut checked for being loose it's real common for the later S model saturns for that nut to loosen up and cause a delay or no reverse if the nut get's loose enough. Also valve body issue's cause pressure issue's in the transmission causing delay bang's and those two transmission code's you have. Let's get the transmission code's fixed first then worry about the other code's. The other code's really aren't that serous like the transmission code's are.I wouldn't just take it any where a lot of place's will want to just remove the transmission and tear it down without testing anything. Most likely you will have to have the input nut checked for looseness because there really isn't anyway I have found to see if it's loose without physically checking it and replacing the valve body. You will need to ask question's like how they will be diagnosing the problem then relay the information to me and I will help you keep them honest and help you figure out if they know what there talking about.I have had to fix a few transmission's for the transmission shop's one tore apart the whole transmission rebuilt it and still had the same problem. All that was wrong was a bad line pressure solenoid. That was a major transmission chain also AA**o you can figure that one out.I had more then one of that chain call with problem's fixing that transmission. Most of the time it's a in car repair haven't had to remove many for repair compared to the one's I fixed in the car.