1. Low Voltage/Charging System Issues: This is the most likely culprit. The flashing wait-to-start light is the truck's way of saying it's not getting enough voltage. This prevents the engine computer from functioning properly, leading to the transmission problems (no OD) and preventing the engine from starting reliably.
* Alternator Failure: The most common cause. The alternator isn't generating enough power to charge the battery. This could be due to a bad alternator, failing alternator bearings, bad wiring to the alternator, a bad voltage regulator (internal or external, depending on your alternator), or a broken alternator belt.
* Battery Problems: A weak or failing battery won't hold a charge, even if the alternator is working. Check the battery's voltage with a multimeter. It should be around 12.6V when fully charged. A load test can determine its ability to deliver current under load. Corrosion on the battery terminals is also a common problem that impedes current flow.
* Wiring Issues: Damaged or corroded wiring in the charging system circuit can prevent proper current flow, mimicking the symptoms of a bad alternator or battery. Check all wiring connections from the battery, to the alternator, and to the starter.
2. PCM (Powertrain Control Module) Problems: Since the transmission isn't shifting into overdrive, and the wait-to-start light is flashing (indicating a communication problem), the PCM might be malfunctioning. A bad PCM can cause a variety of issues, including those you're experiencing. This is less likely than a charging system issue, but it's possible.
3. Transmission Issues (Less Likely given other symptoms): While transmission problems can cause shifting issues, the other symptoms (no charge, flashing wait-to-start) strongly suggest a primary electrical problem. However, low voltage *could* cause the transmission to malfunction, but fixing the electrical issues should be the first step.
Troubleshooting Steps:
1. Check Battery Voltage: Use a multimeter to measure the battery voltage both with the engine off and running. Low voltage with the engine off indicates a bad battery. Low or no increase in voltage with the engine running indicates an alternator problem.
2. Inspect Alternator Belt: Check for wear, breakage, or slippage.
3. Check Battery Terminals: Clean any corrosion from the battery terminals and cables.
4. Test Alternator Output: A more thorough test requires a multimeter to check the alternator's output voltage while running. Consult a repair manual for the correct voltage specifications.
5. Inspect Wiring: Look for any damaged, loose, or corroded wiring in the charging system, particularly around the alternator, battery, and starter.
6. Have the Alternator Tested: If you suspect the alternator, have it tested at an auto parts store. Many stores will test alternators for free.
7. Check PCM Codes: Using a code reader for your year and model Dodge will help determine if there are any stored diagnostic trouble codes (DTCs) within the PCM which might shed more light on the problem.
Important Note: Don't just replace parts randomly. Systematic troubleshooting is essential to pinpoint the root cause. A multimeter is crucial for accurate diagnosis. If you're not comfortable working on electrical systems, take it to a qualified mechanic specializing in older diesel trucks. Improperly diagnosing and repairing electrical systems can lead to more damage.
