1975 cadillac coup deville acts like brakes or parking brakes are locked up engaged. In a bind and will barely move in gear. parking brake pedal is up in the disengaged position. Help?

Something wrong with the shift lock system maybe. Safety system that won't allow the gear selector to move from park unless the driver is pushing the brake pedal . Do your brake light's work ? Does your caddy have floor or column shift ?
Automatic Transmission Shift Lock Control Description and Operation (Floor Shift)
The automatic transmission shift lock control system is a safety device that prevents an inadvertent shift out of PARK when the engine is running. The driver must press the brake pedal before moving the shift lever out of the PARK position. The system consists of the following components:
• The automatic transmission shift lock solenoid (serviced as the automatic transmission shift lock actuator), as well as the body control module (BCM) and the engine control module (ECM).The shift lock solenoid is located within the floor shift control assembly with vehicles equipped with floor shift.
• The BCM controls the voltage supply circuit of the shift lock control solenoid. The following conditions must be before the BCM will supply voltage to the shift lock control solenoid.
The BCM controls the voltage to the shift lock control solenoid through the shift lock control solenoid controlled voltage circuit. The following conditions must be met before the BCM will supply voltage to the shift lock solenoid:
• The ignition is in the ON position.
• The ECM sends an input via GMLAN serial data to the BCM indicating the transmission is in the PARK position.
• The BCM determines the brake pedal is applied according the brake pedal position.
Since the shift lock control solenoid is permanently grounded, the BCM supplies voltage to the automatic transmission shift lock control solenoid, mechanically unlocking the shift lever allowing the driver to move the shift lever out of the PARK position as the solenoid energizes. When the brake pedal is not applied, the BCM turns the control voltage output of the shift lock control solenoid OFF, de-energizing the shift lock control solenoid. The de-energized solenoid mechanically locks the shift lever in the PARK position.
During remote start operation, the BCM will de-energize the shift lock control circuit, locking the shift lever in the PARK position.

Do you have column or floor shifter ?
All automatic transaxle models use an electric park lock system. Within the housing assembly, a lock cylinder is connected to an actuator which rotates and engages on the electric park lock solenoid. When the floor-shift lever is not in the park position, the actuator disengages from the electric park lock solenoid slider. This allows the lock cylinder to move to the lock position. With the shift lever in PARK and the lock cylinder in LOCK, the actuator cam is positioned against the electric park lock solenoid slider. This prevents the shift lever from shifting out of the PARK position.
The column-shift automatic transaxle model uses a flexible cable actuator instead of an electric park lock system. One end of the cable is attached to the gate assembly. The other end of the cable is attached to the column mounted housing assembly. This system functions similarly to the floor-shift ignition lock system.
The manual transaxle model uses a push button lock cylinder. A clutch start switch is used. The clutch pedal must be pressed before the engine will crank. Refer to Park Lock System Check .
CAN you turn the key on ?
The gear selector does not shift out of PARK with the brake pedal depressed and the ignition switch in RUN.
Automatic Transmission Shift Lock Control Always On with Ignition in Run
Action
Value(s)
Yes
No

1

Was the BTSI System Check performed?
--
Go to Step 2
Go to Automatic Transmission Shift Lock Control System Check

2

Is this a column shift vehicle?
--
Go to Step 3 yes
Go to Step 4 no

3

1. Move the gear selector to the PARK position.
2. Disconnect the automatic transaxle control connector
3. Turn the ignition switch to RUN.
4. Connect the test lamp between terminal B and ground.

Does the test lamp light?
--
Go to Step 4
Go to Step 8

4

1. Disconnect the brake switch connector C2.
2. Move the ignition switch to RUN.

Can you shift the transaxle out of the PARK position?
--
Go to Step 5
Go to Step 8

5

Is the brake switch adjusted properly?
--
Go to Step 6
Go to Step 7

6

Replace the brake switch.
Is the repair complete?
--
System OK
--

7

Adjust the brake switch.
Is the repair complete?
--
System OK
--

8

1. Disconnect the BTSI solenoid connector (column shift vehicles) or disconnect the automatic transaxle control connector (console shift vehicles).
2. Move the ignition switch to RUN.

Can you shift the transaxle out of the PARK position?
--
Go to Step 9
Go to Step 10

9

Repair the short to power in CKT 1135.
Is the repair complete?
--
System OK
--

10

Test for sticking or binding in the shift linkage.
Does the shift linkage stick or bind?
--
Go to Step 11
Go to Step 12

11

Repair the shift linkage.
Is the repair complete?
--
System OK
--

12

Replace the BTSI solenoid (column shift vehicles) or replace the automatic transaxle control (console shift vehicles).
Is the repair complete?
--
System OK
Go to Step 1

Could be the brake pedal switch which allows gears to change has become dislodged or failed.

It should move freely with the transmission in neutral and parking brake released. The parking brake may be stuck engaged - it should release if you put the transmission in drive first (manually check that the parking brake pedal has released).

Simple thing is that the brake sensor is not reading that you have you foot on the brake pedal. Not sure where it is on your Caddy, however. Check to see if your brake lights come on, on some cars I believe the two were connected.

Is your car Parked on a hill. Do you use the E-brake.
1st. Make sure you, press the bake peddle.
2nd.If the car is parked on a little hill facing up or down
you'll need to move the car a little. Up or down.
3rd. When the car is parked not level the transmission
parking PAW or PARKING lock inside the Transmission
may have to mush pressure on on it to move easily
So, that is probably the problem. Move the car eighter way
to relieve the presser off the parking Paw. When parking the car
when stoped, Leave your foot presure on the brake pedal.
set the E- Brake then put, the trans into PARK.This way
The presure, in the trans parking lock is not to tight.

Hello, Look up under the dash next to the inside of the car, between the foot pedal for the park brake assembly, on the park brake assembly there should be a short lever, it may even be yellow on the end. pull it back toward you, that should release the park brake. The System is suppose to release automatically when you put the car in gear. It works off vacuum, the switch is mounted on top of the steering column and the actuator is mounted on the park brake assembly

there is a manual release on the park brake assembly I think yellow tip lever. The unit releaases automatic by vaccum, if there is vaccum to the release vaccum solenoid but it doesn't release you need a new solenoid

The parking brakes unlock automaticly when shifted into gear. If it is not working the actuator for the release is at fault. It is located ablove the parking brake pedal. The part is not that expensive as well at any Cadillac dealer

Although you've released the parking brake, inside the car, are you sure the cable moved and disengaged the rear brakes ? A physical removal of the rear wheels will be required and parking brake cable and linkage operation inspected. If the cable appears to be a BINDING , a heavy dose of WD-40 will cure it. Hope this helps