Transmission

Check your fluid level as described in your Owners Manual. At normal operating temp, engine running, Vehicle in Park and Park brake applied.If the fluid level is OK, you may have an internal parts failure. Transaxle malfunctions may be caused by these general conditions: Poor engine performance Improper adjustments Hydraulic malfunctions Mechanical malfunctions Electronic malfunctions Diagnosis of these problems should always begin by checking the easily accessible variables: fluid level and condition, gearshift cable adjustment. Then perform a road test to determine if the problem has been corrected or that more diagnosis is necessary. If the problem persists after the preliminary tests and corrections are completed, hydraulic pressure checks should be performed.

If your Caravan is downshifting to 2nd gear and remaining there. The computer is putting it in "limp mode" or "safe mode" This is so you can limp home or to a shop at a slow speed. Take it to a good diagnostics shop so they can run the codes and understand that the problem may have nothing to do with the transmission. The problem could be anything that the computer has detected and determined that you should not drive the car in current condition.

there is a transmission control computer on the firewall that causes this. mine had a short and we replaced it and now it don't do that any more.