A car rolling chassis is basically the complete body, suspension, steering system and transmission of the car. It does not, however, have an engine yet nor does it have any of the upgraded accessories that drivers choose once the car is completely put together. If you have repairs that need to be done, here is a layout of what you may have to do.
Step 1 - Body
The body of the rolling chassis is much like other car bodies and can be repaired in similar ways. Often times you may need a paint job or if there is a dent that needs to be fixed you can either suction it out or hammer out the dent in the opposite way. Scratches can be filled in and then painted over or you can buy a filler in the same color paint that the body is.
Step 2 - Suspension
The suspension is basically to keep the car running evenly on the ground and make the ride as comfortable as possible for the driver. If you have a problem here you can tell if the ride is bumpy. Generally, you would need to fix or replace the springs. When there is something wrong with the springs it will cause the seats to go up and down with the car instead of holding still. Shock absorbers are also part of this section and they provide control over the bumpy ride. If replacing the springs does not fix the problem then new shock absorbers will be your next step.
Step 3 - Steering System
If you are experiencing a shimmy when you are steering then this is the result of an imbalance. You will want to check each wheel to make sure that it isn't bent. You can tell this by lifting up the car and manually rotating each wheel while watching to see if it favors one side to the other. If this is the problem then you will want to get a replacement. if it is even .050 of an inch sideways there could end up being major problems with the car if you drive on it. Replacing right away is your best option.
Step 4 - Transmission
For the transmission you will want to check a few things if you are experiencing a problem. You will want to replace any fluids. This is a likely answer to most of the problems. If this does not fix it then you can move on to the gears and filter. You will want to check to see if the gears are cracked or broken or if the filters are dirty and if so a replacement or cleaning will be in order. Finally, check the bell housing to make sure that the center is not stuck on either side and if it is it will need to be loosened.
Most likely your problem can be fixed under one of these categories.