Here's why both issues are connected and what to check:
* Brakes: The brake booster uses engine vacuum to multiply the force applied to the brake pedal. Without sufficient vacuum, the pedal will feel very hard and brakes will be ineffective or non-existent.
* Transmission (Automatic): Many automatic transmissions rely on engine vacuum for the shift linkage or the modulator valve (controls shift pressure). Loss of vacuum will prevent proper shifting, often leading to the inability to shift out of Park.
Troubleshooting Steps:
1. Check for Vacuum Leaks: This is the most likely culprit. Inspect all vacuum lines connected to the brake booster. Look for cracks, loose connections, or any damage. Pay close attention to the line running from the intake manifold to the booster. You might even use a spray bottle with soapy water – if bubbles appear when spraying around connections, you've found a leak.
2. Check the Vacuum Line Routing: Make sure the vacuum line from the intake manifold is correctly connected to the brake booster. An incorrect routing will prevent the booster from working.
3. Inspect the Brake Booster Itself: Ensure you installed the new brake booster correctly and that the vacuum connection is airtight. A faulty new booster (though less likely) is still possible.
4. Check the Vacuum Source (Intake Manifold): A very rare possibility is a significant problem with your engine's vacuum system preventing sufficient vacuum from reaching the booster. This is less likely if other vacuum-dependent systems on your truck (like the power brakes) are also affected.
5. Master Cylinder: While less likely given the transmission issue, a faulty master cylinder could also contribute to brake failure. However, the transmission issue makes this less probable.
Important Note: If you aren't comfortable working on your vehicle's braking system, take it to a qualified mechanic immediately. Driving a vehicle with faulty brakes is extremely dangerous.
