* Low/Dirty Transmission Fluid: This is the first thing to check. Low fluid level can cause shifting problems, and dirty fluid can damage the transmission's internal components. Check the fluid level while the engine is running and warm, and note the color and condition (it should be reddish-pink and clear, not brown or black and gritty).
* Faulty 2-3 Shift Solenoid or Valve: The 700R4 uses solenoids and valves to control shifting. A faulty solenoid or valve can prevent the transmission from engaging second gear. This often manifests as skipping second gear entirely.
* Worn or Damaged Clutch Pack (2nd gear): The clutch packs are responsible for engaging the gears. Wear or damage to the second gear clutch pack can prevent it from engaging properly. This is a more serious internal problem.
* Problems with the Transmission Valve Body: The valve body houses the various valves and passages that control fluid flow throughout the transmission. Internal problems within the valve body can interfere with gear selection.
* Broken or Worn Shift Linkage: While less common, a problem with the linkage that connects the shifter to the transmission can prevent it from selecting second gear.
* Low Line Pressure: Insufficient hydraulic pressure in the transmission system can also lead to shifting issues. This often requires a more in-depth mechanical diagnosis.
* Torque Converter Issues: Though less likely to cause *only* second gear failure, a failing torque converter could contribute to shifting problems.
What to do:
1. Check the transmission fluid: This is the easiest and cheapest check. If it's low or dirty, add the correct type of ATF (Automatic Transmission Fluid) or have it flushed and replaced.
2. Consult a repair manual: A repair manual specific to your 1994 Chevy pickup and 700R4 transmission will provide detailed diagrams and troubleshooting steps.
3. Seek professional help: Unless you have significant experience working on transmissions, it's best to take your truck to a qualified transmission specialist or mechanic. Diagnosing transmission problems requires specialized tools and knowledge. They can perform a proper diagnosis and recommend the appropriate repairs. Ignoring the problem could lead to more extensive and costly damage.
