how much will the cable cost to fix the shifter,to stop it from bouncing back

I am a trans guy. I have seen this problem before. You will need a new shifter cable but you need to fix another problem with the shifter cable. The manual linkage in the trans need some attention. It can be costly but how I go about fixing this problem is. 1. I replace a cable 2. Remove the valve body and install a transgo update kit 3. Hone the trans case were the shifter rod goes through. What the problem is that the rod is too tight in the trans housing. I put the kit in the valve body is due to the problems with this transmission that make this trans go bad. If there is no problems with the trans then there won't be any problems in the future. But most of the time the car has 160000 miles on it and the trans needs help. So at that point I give out my menu price of a trans overhaul. In this case i can repair this car for about 2000