The short answer is yes — if you suspect an issue with your transmission.
You may have experienced a problem with your transmission or are just encountering an issue at present. Perhaps you think you might drive on without an issue, but you should conduct a transmission inspection to rule out any issues.
“I can just use an OBD-II scanner and fix the issue myself,” you might be thinking. While you might be tempted to read the error code on a diagnostic scanner like an OBD-II scanner, sometimes the OBD-II scanner displays that an issue is occurring in a specific part of a truck, but the scanner doesn’t share the root cause of the issue.
If your check-engine light is on, or if you’re wondering whether your transmission is acting up, we recommend bringing it to a diesel truck repair shop for an inspection just in case. Still skeptical?
If you’re wondering whether your truck needs a transmission inspection, we encourage you to read on. In this article, we’ll discuss the importance of bringing your truck in for a transmission inspection to address the following transmission-related issues and concerns:
Before we dive into whether a transmission inspection is needed, we first need to understand the range of issues that can lead to transmissions.
Transmission issues tend to come in all different shapes, sizes, and textures. Below are some of the most common signs and symptoms that indicate a vehicle’s transmission needs troubleshooting:
| Transmission issue | What this issue indicates |
| Difficulty shifting gears | May indicate low transmission fluid, a worn clutch, or damage to the truck’s gears |
| The transmission is “slipping” | May indicate a failing clutch, valve body issues, or issues with torque |
| Leaking fluid beneath the truck’s interior | Damaged pan gasket, cooler lines, or transmission seals |
| Burning smells | Your transmission fluid may have overheated due to friction between parts or other issues within the truck |
| “Check Engine” light turns on | An internal computer code has turned on in the truck’s computer, indicating an issue with or around the transmission |
| Grinding, humming, or whining noises | You may have experienced internal damage to internal components or gears |
| Inconsistent shifting or gear issues | Low transmission fluid levels or dirty/ old transmission fluid could be the culprit |
| The truck won’t move in its gear | Your truck may be experiencing engine failure or transmission issues |
If you’re noticing any of the indicators above, which could signal issues with a transmission, you may want to start by observing the condition of your truck’s transmission fluid. You can determine the condition and level of transmission fluid by looking at the following:
If you’re unsure if you have an issue with the transmission of your vehicle, we highly recommend bringing it to a shop for repairs. In-shop repair technicians can place the vehicle on a lift so that the diesel can be inspected up close and diagnosed with greater accuracy.
Sometimes, though, a mere visual inspection doesn’t always cut it. On occasion, test-driving a truck can help you diagnose transmission issues with greater ease.
An experienced mobile repair technician will drive the vehicle in a variety of conditions to reproduce the transmission issues. The technician will inspect the vehicle for the following five common transmission issues:
A physical test drive is key in helping you and your diesel repair technician determine whether the issue under your hood is a result of the mechanic parts, electrical wiring, or fluid levels in your truck.
If you’re savvy and considering a transmission repair on your vehicle, we recommend pausing first and checking in with a technician. The reason is that you may have used a diagnostics scanner and found a code mentioning something is wrong with the transmission via your vehicle’s computer.
The issue is that you might be misdiagnosing a symptom for the problem, when the error code may just be a result of a faulty issue unrelated to the transmission.
Enlisting the eyes of an experienced mechanic can help you better understand the source of the error code, warning light, or data you’re receiving from your vehicle’s onboard computer.
Also, the technology under the hood of vehicles is always changing. Diesel repair technicians are trained in and responsible for staying up to date with vehicle diagnostic codes.
Your diesel repair technician may come to a different conclusion than you, because of their experience and knowledge of how error codes work within the systems of your vehicle.
As a result, we always recommend reaching out to a diesel repair technician, even if just for a second opinion on your truck’s transmission.
🍁 Cooler weather is here! Make sure your fleet is ready for the fall and winter seasons. Check out our fall maintenance checklist for key safety, tune-up, brake, and compliance-related fixes you can make to keep your transmission — and truck — healthy and happy all season long.
Yes, transmission inspections are a must, especially if you think your truck is experiencing issues with its transmission.
With the commercial transmission market projected to grow 4.2% from this year until 2033 (ProMarketReports.com, 2025), you couldn’t have picked a better time — or truck part — to receive support from your local mechanic. The more transmissions that are sold on the market, the better chance you stand of receiving top-quality service, repairs, and rebuilds for your new transmission.
That’s what we pride ourselves on delivering to new and returning customers. We’re all about providing expert advice, top-quality repairs, and efficient, speedy service.
If you’re in the Tacoma, Washington area, and you’d like help with your diesel’s transmission, don’t hesitate to give us a call at (253) 365-6591 for a quick and convenient in-shop or mobile truck repair appointment. Our diesel repair technicians have over 20 years of dedicated experience repairing and servicing diesel-powered equipment and trucks of all shapes and sizes.
For truck support from Tacoma, Washington’s premiere diesel experts, contact us today. Let the Experts take care of and provide you with professional and comprehensive diesel service.
Equipment Experts: Providing Thorough Automatic and Manual Transmission Inspections
