Chevrolet Repair: question about a chevy berretta, chevy berretta, gas mileage

Question
Would a speed control sensor be the problem for my car not wanting to shift or go in drive. At first I had to warm it up and then it would go into gear. My son unhooked the crankshaft lock up(?) and it would go into drive but not reverse. PLease help!

Answer
Hello Penny.....You must first know whether you have a four speed transmission or a 3 speed transmission. In either case, disconnecting anything will not prevent any transmission from going forward or backwards. If you have a 3 speed the selector will read PRND21 OR PRN321. If you have a 4 speed the selector will read PRND321 OR PRND(WITH A CIRCLE AROUND IT)321. If the transmission is a three speed have your son drop the lower pan and install a new filter and seal. The three speeds had a problem with the filter falling off or at least coming loose. The 4 speeds on the other hand have a problem with the ''input'' clutch drum and that is a little too complicated for us to fix here.Make sure the fluid level in full after the vehicle is warmed up What your son probably disconnected is the torque converter ''lock-up'' solenoid on the front side of the 125c three speed transmission. This will only hurt your gas mileage and create undo heat for the transmission...Try and see ...best