Finding Your Allison Transmission Temp Sensor Location
Finding your allison transmission temp sensor location isn't always as simple as looking with regard to a spark put or an essential oil dipstick, mostly due to the fact these heavy-duty models like to maintain their sensitive elements tucked away. If you're driving a Silverado or Sierra with a Duramax, or maybe a medium-duty work truck, you most likely already know that will Allison transmissions are usually absolute beasts. But even the most difficult gearboxes have their particular "bad days, " and a faulty temp sensor is the common culprit when your dash starts acting funky or maybe the truck goes straight into limp mode.
Usually, when somebody asks where the sensor is, they're hoping for a fast plug-and-play fix on the side of the casing. I hate in order to be the bearer of bad information, but for most modern Allison 1000 and 2000 collection transmissions, the temp sensor is in fact located within the transmission . It sits directly on the valve entire body, integrated into the particular internal wiring control. This means you aren't just reaching under the vehicle having a wrench; you're going to have in order to drop the skillet and get your hands a little oily.
Why the Internal Location Issues
You may question why engineers would certainly put a sensor inside the transmission where it's more difficult to reach. Well, it's all about accuracy. By placing the sensor directly on the inner harness or the particular pressure switch manifold, the computer will get a real-time reading of the liquid temperature as it circulates with the nearly all critical parts of the device.
In the event that you've got a good older Allison, state from the early 2000s, the sensor is often part of the internal wire harness assembly . In these models, the thermistor (the actual sensing element) is clipped directly into the harness itself. If the sensor fails, you're usually replacing that whole internal harness area. It sounds intimidating, but it's really quite a common restoration for anybody who will their own upkeep.
Signs You should Find the Sensor
Before you go through the trouble of falling the pan, a person want to be sure that the allison transmission temp sensor location will be actually where your own problem lies. There are some telltale signs that this little part has given up the particular ghost.
The particular most obvious the first is a "Trans Temp" gauge that's either stuck at the bottom or pinned at the maximum. If you begin your truck upon a freezing early morning and the measure immediately jumps to 250 degrees, you've clearly got the issue. Another red flag is the dreaded P0711, P0712, or P0713 diagnostic trouble codes. These codes basically tell the ECM that the temperature signal is away of range or even totally missing.
Sometimes, the transmission will even decline to shift in to overdrive or will certainly stay in the "limp mode" to protect itself through perceived overheating. It's frustrating once you understand the truck is usually cold, but the computer thinks it's melting down. That's when you know it's time for you to get under there.
Being able to access the Sensor Step-by-Step
Since we've established the allison transmission temp sensor location is usually internal, you'll want to prepare for a fluid change in the same period. Here's how you in fact get to it:
- Empty the Fluid: There's the drain plug within the bottom of the pan. Use this. Allison pans hold a fair amount of fluid, so make sure your catch bucket is big enough.
- Remove the particular Pan: You'll have a number of or so bolts to remove. Keep some in place till you're ready to lower it, or you'll end up with a transmission fluid shower.
- Recognize the Harness: After the skillet is off, you'll see the valve body. Looking up at it, you'll view a plastic wiring harness with different colored wires heading to solenoids.
- Locate the Sensor: On most multitude of series units, the particular temp sensor is really a small, black plastic material piece clipped to the harness, usually near the front or side of the control device body. It appears like a tiny put with two cables.
It's important to note that if you're functioning on a 6-speed Allison (roughly 2006 and newer), the sensor is frequently incorporated into the Internal Wiring Harness . When the sensor is bad, you replace the particular harness. On the particular 5-speed versions, it was sometimes a separate, replaceable element, but the funnel is generally the way to go intended for a long-term repair.
Is It the particular Sensor or the Exterior Wiring?
Just before you tear in to the transmission pan, there is one "gotcha" you need to check. The allison transmission temp sensor location may be internal, but the wires have to come out of the case somewhere. Upon the back of the transmission, around the passenger side, there's a large circular connector. This is definitely where the internal harness plugs in to the truck's primary wiring.
Sometimes, oil can leak into this connection, or the pins can get damaged from road sodium and grime. In case that connection is definitely dirty, it can cause the exact same symptoms as a poor sensor. I always recommend unplugging that external connector plus creating a great blast with some digital cleaner. If the pins look bent or green with corrosion, that might end up being your real issue. It's a lot easier to clean a plug than you should drop the pan and exchange a harness.
What About the Pressure Switch Manifold?
In certain specific Allison models, the temperature sensor is in fact a part of the Pressure Switch A lot more (PSM) . This particular is a smooth component bolted in order to the bottom associated with the valve body. It has a number of diaphragm switches that tell the computer what gear the particular transmission is within, plus the temp sensor is often cooked right into this assembly.
If a person have a mid-2000s truck and you're getting shift mistakes along with temp readings that don't seem sensible, the PSM is a likely applicant. Replacing it isn't much harder as opposed to the way replacing a funnel, but it's one more reason why understanding the exact allison transmission temp sensor location is dependent slightly on your own specific model season.
Tools You'll Requirement for the Work
If you've decided to tackle this yourself, a person don't need a massive shop, yet several specific equipment will make your existence much easier. * A 15mm socket: For the drain plug. * The 13mm socket: For the particular pan bolts. * Rpm Wrench: This is non-negotiable. The pan mounting bolts and the valve body components are made of aluminum. If you over-tighten them, you're heading to have a very bad day. * A brand new Filtration system: Considering that you're in there, you should definitely substitute the internal "sump" filter. Don't forget the external spin-on filter either! * Quality Fluid: Allisons are particular. Use a high-quality fluid like Transynd or a Dexron VI equivalent, depending on what your manual specifies.
Final Thoughts around the Swap
Dealing with a faulty sensor is annoying, yet it's one associated with those things that keeps your transmission alive. Without an precise temperature reading, the particular TCM (Transmission Handle Module) can't adapt the line pressure or shift timing correctly for cold or hot fluid.
Remember, while the allison transmission temp sensor location is nestled away inside, the task is mostly just the glorified fluid switch. Take your time, keep everything surgically clean—transmissions detest dirt—and make sure the new use or sensor steps securely into location. Once you've started using it back together plus topped off with fresh fluid, your own gauge should behave again, and your Allison will proceed back to doing what it does best: pulling weighty loads without breaking a sweat.
If you're still seeing weird psychic readings after a substitute, it's worth looking at the TCM itself, but nine times away from 10, it's either the particular internal sensor or that big circular plug on the particular outside from the situation. Happy wrenching!