1987 Nissan Pickup Speedometer Not Working

Hey there! Running into a little trouble with the speedometer on your 1987 Nissan Pickup? A non-functional speedometer can be frustrating, especially since it affects your ability to accurately gauge your speed and mileage. Let's walk through the common causes and how you can diagnose and potentially fix this problem yourself. We’ll keep it practical and provide some estimated costs, so you know what you're getting into.

Understanding the Problem: Why Your Speedometer Quit

Before diving into the fixes, it's important to understand what makes your speedometer tick. In a 1987 Nissan Pickup, the speedometer is mechanically driven. This means a cable connects your transmission to the back of the instrument cluster. As the transmission spins, the cable rotates, which then turns the speedometer needle. Therefore, the problem likely lies in one of these areas:

Speedometer Cable Issues: This is the most common culprit. The cable can break, become disconnected, or get kinked.
Transmission Speedometer Gear: Inside the transmission, a gear drives the speedometer cable. If this gear is worn or damaged, it won't properly rotate the cable.
Instrument Cluster Problem: The speedometer mechanism itself within the instrument cluster can fail, although this is less common than cable or gear issues.
Wiring (Less Likely but Possible): Though mechanically driven, some lighting and grounding issues *within* the instrument cluster could indirectly affect its function.

Diagnosis: Pinpointing the Problem

Let's start with the easiest and most likely issues first.

Step 1: Inspect the Speedometer Cable at the Instrument Cluster

Tools Needed: Screwdriver (Phillips and potentially flathead, depending on your dash), possibly a small flashlight.

Access the Instrument Cluster: Gently remove the trim around the instrument cluster. This usually involves removing a few screws. Be careful not to scratch or break the plastic.
Locate the Speedometer Cable: It's a thick cable connected to the back of the speedometer.
Check the Connection: Make sure the cable is securely connected. Sometimes, it can simply come loose. Tighten the connection if possible.
Visual Inspection: Look for any obvious signs of damage to the cable sheath (the outer covering). Kinks, cracks, or breaks are red flags.

Tip: Take pictures of everything as you disassemble it. This will make reassembly much easier!

Step 2: Inspect the Speedometer Cable at the Transmission

Tools Needed: Jack and jack stands, wrench (size will vary, but likely 10mm or 12mm), gloves, safety glasses.

Safety First: Securely jack up the front of your truck and support it with jack stands. Never work under a vehicle supported only by a jack.
Locate the Speedometer Cable on the Transmission: It's usually on the side or rear of the transmission.
Check the Connection: Similar to the instrument cluster end, ensure the cable is securely connected to the transmission.
Check for Damage: Look for the same signs of damage as before – kinks, cracks, or breaks in the cable sheath.

Tip: It's a good idea to wear gloves and safety glasses when working under your truck. A little grime is unavoidable!

Step 3: Testing the Speedometer Cable

Tools Needed: Small square shaft screwdriver or drill with a square bit attachment, pliers.

Disconnect the Cable at the Transmission: Carefully disconnect the cable from the transmission.
Expose the Inner Cable: You should see the end of the inner speedometer cable.
Test Rotation: Use pliers to try to turn the cable from the transmission end. If it rotates freely, this suggests the cable is broken inside. The *inner* cable should be firmly attached to the outer sheath at the instrument cluster end.
Alternative Test (Requires Assistance): With the cable still connected to the instrument cluster, have someone sit in the truck and watch the speedometer. Carefully insert a small square shaft screwdriver (or drill with appropriate square bit) into the cable end at the transmission and manually rotate it. Be extremely careful. If the speedometer needle moves, this confirms the cable is functional and the problem likely lies within the transmission's speedometer gear.

Caution: When manually rotating the cable, do it slowly and smoothly. Jerky movements can damage the instrument cluster.

Step 4: Inspecting the Transmission Speedometer Gear

Tools Needed: Socket set, wrench set, jack and jack stands, drain pan, transmission fluid, RTV sealant (optional).

Drain Some Transmission Fluid: Place a drain pan under the transmission and remove the drain plug (if equipped) or carefully loosen the transmission pan bolts to allow some fluid to drain. You don’t need to drain the entire transmission, just enough to get the fluid level below the speedometer gear housing.
Remove the Speedometer Gear Housing: The speedometer cable housing is typically held in place by a single bolt or retaining clip. Remove it.
Extract the Speedometer Gear: Carefully pull out the speedometer gear. It's usually a small plastic gear.
Inspect the Gear: Look for worn, broken, or missing teeth. If the gear is damaged, it needs to be replaced.
Reinstall: If the gear is in good condition, reinstall it and the housing, ensuring the O-ring or seal is in good condition. Consider using a small amount of RTV sealant to ensure a good seal.
Refill Transmission Fluid: Top off the transmission fluid to the correct level.

Tip: Make sure you know what type of transmission fluid your 1987 Nissan Pickup requires *before* starting this process. Using the wrong fluid can damage your transmission.

Solutions: Getting Your Speedometer Working Again

Based on your diagnosis, here's how to fix the problem:

Replace the Speedometer Cable: If the cable is broken or damaged, this is the most common solution. New speedometer cables are relatively inexpensive and readily available.
- Estimated Cost: $20 - $50 for the cable.
- Installation: Straightforward replacement. Simply disconnect the old cable at both ends and connect the new one. Route the cable the same way as the old one to avoid kinks.
Replace the Transmission Speedometer Gear: If the gear is worn or damaged, replacing it is necessary. Make sure to get the correct gear for your specific transmission and axle ratio.
- Estimated Cost: $15 - $40 for the gear.
- Installation: As described in the diagnosis section.
Instrument Cluster Repair: If you suspect the problem lies within the instrument cluster itself, you have a few options:
- Replacement: Find a used instrument cluster from a junkyard or online. This is often the easiest and most cost-effective option. Estimated Cost: $30 - $100 (used).
- Professional Repair: Some shops specialize in instrument cluster repair. This can be a good option if you want to keep your original cluster. Estimated Cost: $100 - $300.
- DIY Repair (Advanced): If you're comfortable with electronics, you *might* be able to repair the speedometer mechanism yourself. This requires specialized knowledge and tools. Not recommended for beginners.
Check and Repair Wiring: Inspect wiring harnesses and connectors leading to the instrument cluster. Look for corroded or damaged wires. Clean connectors with electrical contact cleaner and repair or replace damaged wires.
- Estimated Cost: Varies greatly depending on the problem and solutions
- Installation: Use a multimeter to test for continuity and voltage. Repair or replace wires and connectors as needed.

Preventative Maintenance

To keep your speedometer working smoothly in the future, consider these tips:

Avoid Sharp Bends: When routing or replacing the speedometer cable, avoid sharp bends that can kink or damage the cable.
Regular Inspection: Periodically inspect the speedometer cable for signs of wear or damage.
Lubrication (Optional): Some older cables can be lubricated with a graphite-based lubricant. Consult your vehicle's service manual for recommendations.

Important Note: The estimated costs provided are just that – estimates. Actual costs may vary depending on your location, the parts supplier, and whether you do the work yourself or hire a professional mechanic.

By following these steps, you should be able to diagnose and fix most speedometer problems on your 1987 Nissan Pickup. Good luck, and happy motoring!