* Transmission Issues: This is the most likely suspect given your description. The symptoms suggest a problem with the automatic transmission's ability to engage properly, especially under load. Here are possibilities:
* Low Transmission Fluid: Check your transmission fluid level. Low fluid can cause slipping, sluggish acceleration, and shaking. Also, check the fluid's condition – it should be bright red, not dark brown or burnt smelling.
* Worn Transmission Bands or Clutches: These components wear out over time and can cause slippage and poor shifting. This requires a transmission rebuild or replacement.
* Torque Converter Problems: The torque converter connects the engine to the transmission. Problems here can also cause slippage.
* Solenoid or Valve Body Issues: These control the transmission's shifting. A faulty solenoid or valve body can lead to erratic shifting and poor performance.
* Engine Problems: While less likely given the specific description, engine issues *could* contribute:
* Spark Plugs/Wires: Worn or faulty spark plugs and wires can cause misfires, leading to poor acceleration and shaking.
* Ignition Coil: A failing ignition coil can also cause misfires.
* Fuel System Issues: A clogged fuel filter, malfunctioning fuel pump, or dirty injectors can restrict fuel delivery, resulting in poor performance.
* Mass Airflow Sensor (MAF): A dirty or faulty MAF sensor can give the engine incorrect information about the air intake, leading to poor running.
* Drivetrain Problems:
* U-joints: Worn universal joints in the driveshaft can cause vibrations and power loss.
What to do:
1. Check the Transmission Fluid: This is the easiest and cheapest check. Do this first!
2. Check Engine Light: Is the check engine light on? If so, have the codes read at an auto parts store (often free) to get clues about potential issues.
3. Listen Carefully: When the shaking occurs, listen closely to the engine and transmission. Are there any unusual noises like whining, grinding, or banging?
4. Professional Diagnosis: Given the combination of symptoms, taking your Blazer to a qualified mechanic for a proper diagnosis is recommended. They have the tools and expertise to pinpoint the exact problem. Describing the symptoms (sluggish acceleration, shaking, only happens when accelerating) will help them narrow down the possibilities.
Your dad's intuition about a transmission problem is plausible, but there are other possibilities. A professional diagnosis is the best way to solve this. Don't continue driving it extensively with these problems as you could cause more damage.
