How To Adjust Automatic Transmission Shift Cable Shift linkage serves as the vital connection between your gear lever and the transmission, and when it’s not in good condition, it can lead to several issues. In this article, we’ll delve into the mechanics of shift linkage, how to identify signs of trouble, and most importantly, how to fix these problems yourself. By following these steps, you can save a considerable amount that would otherwise be spent on professional labor.
How Does Shift Linkage Work?
For those of us who possess some knowledge about the inner workings of powertrains, any transmission-related issue raises immediate concerns. However, it’s important to note that while most transmission problems require specialized expertise, shift linkage issues are often straightforward.
In essence, shift linkage consists of a cable connecting the gear selector lever to the transmission. When you shift gears using the gear lever, you mechanically switch the transmission mode between park, reverse, neutral, and various forward drive modes.
Symptoms of a Failing Shift Linkage:
Identifying shift linkage problems is crucial as these issues can cause the transmission to malfunction while the engine itself remains operational.
- Gear Shifting Problems: One of the most noticeable signs of linkage trouble is difficulty shifting the gear selector through various positions. As the issue worsens, shifting into neutral or drive becomes increasingly challenging.
- Mismatching Gears: When the linkage collet loosens or the cable stretches due to years of use, the cable’s travel length between different positions may not be sufficient to change gears on the transmission. For example, shifting from park to reverse may not engage the reverse gear, leading to gear mismatches.
- Engine Won’t Turn Off: Some vehicles have a safety feature that prevents the engine from shutting down unless the gear shifter is in the park or neutral position. When shift linkage problems cause gear mismatches, the vehicle may remain in reverse even when you try to put it in park, making it challenging to turn off the engine.
- Engine Won’t Start: Most vehicles with automatic transmissions won’t allow the engine to start unless the gear shifter is in park or, rarely, neutral. While this symptom is challenging to identify as everything else may seem normal, cycling the transmission through gears a few times might help you shift it back into park and start the vehicle.
How to Fix Shift Linkage Problems:
There are a couple of failures that can lead to shift linkage problems, and here are the two that you can address at home: adjusting the cable length and repairing the linkage collet.
Adjusting Cable Length:
Adjusting the length of the shift linkage cable is a delicate process but relatively straightforward. You’ll need a helper to shift gears while you make adjustments from beneath the vehicle.
Here’s a step-by-step guide:
- Ensure your helper is in the driver’s seat before you start.
- Safely raise the front of the vehicle using jack stands and secure the rear wheels with wheel chocks.
- Confirm that the vehicle is securely elevated before proceeding.
- Instruct your helper to place the transmission in neutral while you observe the movement of the transmission bracket.
- Behind the bracket, you’ll find a pair of nuts on a threaded rod. Use two wrenches to gently tighten these nuts.
- Have your helper cycle through the gears again while you monitor the bracket’s movement.
- If the cable is still too loose to follow the gear selector’s movement, return the selector to neutral and repeat the process.
- Be cautious not to overtighten the cable, as this could result in damage.
How to Repair the Shift Collet:
In some shift linkage systems, a collet (or bushing) sits between the cable and the transmission bracket. When this collet breaks or wears out, it can create enough distance for the gears not to synchronize or even cause the cable to disengage.
Here’s how to address this issue:
- Raise the front of the vehicle using jack stands and secure the rear wheels.
- Examine the point where the bracket and shift linkage connect to check for a worn or missing collet.
- Measure the diameter of the linkage hole and the bracket mount.
- The replacement collet should be a bushing that fits perfectly on the bracket mount. Trim it to size with a scalpel if it’s too large.
- Place a washer on the bracket mount and apply some grease.
- Grease the makeshift collet and insert it into the shift linkage, sliding it over the bracket mount.
- Secure the collet from falling out by placing a second washer over it.
- Use a retaining clip at the end to hold everything together.
- Can automatic transmission be adjusted? Shifting gear problems related to shift linkage can be fixed by adjusting it or replacing the assembly. However, internal transmission issues should be addressed by professionals.
- Does an automatic transmission have a shift linkage? Yes, automatic transmissions have a shift linkage that connects the gear shift lever to the transmission bracket, allowing the driver to control the transmission mode.
- How much does it cost to fix shift linkage? Repairing shift linkage is relatively inexpensive, with labor costs averaging between $50-100. The shift linkage itself can range from $50 to $200.
- What are the symptoms of a bad shift solenoid? A faulty shift solenoid can lead to symptoms such as a check engine light, transmission warning light, delayed or skipped gears, and general shifting problems.
- Why is my gear shift loose? A loose gear shift lever is often due to a worn or stretched shift linkage cable, which can occur with high mileage and aggressive shifting.
- How much does a shifter bushing cost? A shifter bushing, if purchased separately, is relatively inexpensive, averaging around $10. However, it’s often bundled with the entire shift linkage kit, which can cost more.
Repairing shift linkage issues is a manageable task that requires patience and attention to detail. Adjusting the cable length may require some trial and error, but by proceeding carefully and testing all gears while monitoring the transmission bracket, you can resolve the problem effectively.