* Torque Converter Clutch (TCC): This is the most likely culprit. The TCC locks the engine and transmission together at higher speeds for better fuel efficiency and performance. If the TCC is malfunctioning (sticking, failing to engage properly, or slipping excessively), the added load in "Drive" might be enough to stall the engine. It works fine in Park, Neutral, and Reverse because these gears don't engage the TCC.
* Transmission Problems: Issues within the transmission itself could be responsible. This could include:
* Low Transmission Fluid: Check your transmission fluid level and condition. Low fluid can cause overheating and damage, leading to stalling in Drive. Also, look for burned or discolored fluid.
* Internal Transmission Damage: Worn gears, a failing pump, or other internal problems can prevent the transmission from handling the load in Drive.
* Shift Linkage/Solenoids: A problem with the linkage that controls the transmission shifting, or faulty solenoids that control fluid flow within the transmission, could be preventing the transmission from correctly engaging in Drive.
* Engine Issues: While less likely given the specific situation, engine problems could contribute:
* Crankshaft Position Sensor (CKP): A faulty CKP sensor can provide incorrect information to the engine computer, leading to misfires or stalling, especially under load (like in Drive).
* Throttle Position Sensor (TPS): A bad TPS could provide inaccurate throttle position information, resulting in erratic engine behavior and stalling.
* Ignition System Problems: Worn spark plugs, bad ignition wires, or a failing distributor (if applicable) can cause misfires, particularly under load.
Troubleshooting Steps:
1. Check the transmission fluid: This is the absolute first step. Low or dirty fluid is a common cause of transmission problems.
2. Listen for unusual noises: Any grinding, whining, or banging sounds from the transmission indicate internal problems.
3. Have the transmission scanned for codes: A professional mechanic can plug a scanner into your car's OBD-II port to retrieve any diagnostic trouble codes (DTCs) stored by the transmission control module (TCM). This can pinpoint the problem.
4. Check the engine's basic components: Inspect the spark plugs, wires, and air filter.
Important Note: Since this is a 1995 vehicle, it's crucial to get a professional diagnosis. Attempting complex transmission repairs without experience can cause further damage. The TCC issue is particularly involved and often requires specialized tools and knowledge. A mechanic specializing in older vehicles would be the best option.
