Finding Your Allison Transmission Temp Sensor Location
Finding your allison transmission temp sensor location isn't always as simple as looking intended for a spark plug or an oil dipstick, mostly due to the fact these heavy-duty models like to keep their sensitive elements saved. If you're driving a Silverado or Sierra along with a Duramax, or even maybe a medium-duty work truck, you probably already know that Allison transmissions are absolute beasts. Yet even the hardest gearboxes have their "bad days, " and a faulty temp sensor is a common culprit when your dash starts acting funky or the truck goes into limp mode.
Usually, when somebody asks where the particular sensor is, they're hoping for a quick plug-and-play fix quietly of the casing. I hate in order to be the bearer of bad news, but for many modern Allison a thousand and 2000 collection transmissions, the temperature sensor is in fact located inside the transmission . It sits directly on the valve body, integrated into the internal wiring use. This means a person aren't just achieving under the pickup truck using a wrench; you're likely to have to drop the skillet and get both hands a little greasy.
Why the particular Internal Location Matters
You might wonder why engineers would certainly put a sensor inside the transmission where it's harder to reach. Properly, it's all regarding accuracy. By placing the sensor directly on the inner harness or the particular pressure switch manifold, the computer will get a real-time reading through of the liquid temperature as it circulates through the almost all critical parts of the device.
In case you've got a good older Allison, state from the early 2000s, the sensor is often part of the internal cable harness assembly . In these models, the thermistor (the actual sensing element) is clipped in to the harness itself. If the sensor fails, you're usually replacing that whole internal harness area. It sounds overwhelming, but it's really a pretty common maintenance for anybody who does their own maintenance.
Signs You should Find the Sensor
Before a person go through the particular trouble of falling the pan, a person want to be sure the allison transmission temp sensor location is definitely actually where your problem lies. There are some telltale signs that this little part offers given up the particular ghost.
The particular most obvious one is a "Trans Temp" gauge that's possibly stuck at the bottom or pinned at the maximum. If you begin your truck on a freezing early morning and the gauge immediately jumps to 250 degrees, you've clearly got an electrical issue. Another red light is the dreaded P0711, P0712, or P0713 diagnostic trouble codes. These codes essentially tell the ECM that the heat signal is out there of range or even totally missing.
Sometimes, the transmission will even decline to shift in to overdrive or can stay in a "limp mode" to protect itself from perceived overheating. It's frustrating if you understand the truck is definitely cold, but the particular computer thinks it's melting down. That's when you know it's time to get below there.
Accessing the Sensor Step by step
Since we've established the allison transmission temp sensor location will be internal, you'll need to get ready for a fluid change from the same period. Here's the way you in fact get to it:
- Deplete the Fluid: There's a drain plug around the bottom of the particular pan. Use it. Allison pans keep a fair amount of fluid, so make sure your catch bucket is big enough.
- Remove the Pan: You'll possess a number of or so can be bolted on to remove. Keep a few in place until you're ready in order to lower it, or you'll end up with a transmission fluid shower.
- Identify the Harness: When the pan is off, you'll see the valve body. Looking up at it, you'll see a plastic wires harness with numerous colored wires going to solenoids.
- Locate the Sensor: On most one thousand series units, the particular temp sensor is a small, black plastic piece clipped into the harness, usually close to the front or aspect of the device body. It appears like a little plug with two cables.
It's important to note that if you're functioning on a 6-speed Allison (roughly 2006 and newer), the particular sensor is usually incorporated into the Internal Wires Harness . If the sensor is poor, you replace the harness. On the particular 5-speed versions, this was sometimes a separate, replaceable element, but the funnel is generally the method to go for a long-term repair.
Could it be the particular Sensor or the External Wiring?
Before you tear into the transmission pan, there is one "gotcha" you need to check. The allison transmission temp sensor location might be internal, but the wires have in order to come out associated with the case somewhere. On the back of the transmission, around the passenger side, there's a large round connector. This is usually where the inner harness plugs into the truck's major wiring.
Occasionally, oil can leak into this connector, or the hooks can get corroded from road salt and grime. When that connection is definitely dirty, it may cause the very same signs and symptoms as a bad sensor. I usually recommend unplugging that will external connector and giving it a great blast with some electronic cleaner. When the hooks look bent or green with deterioration, that might become your real problem. It's a great deal easier to clear a plug than it is to drop the pan and change a harness.
How about the Pressure Switch Manifold?
In certain specific Allison models, the temperature sensor is actually a part of the Pressure Switch Manifold (PSM) . This particular is a smooth component bolted to the bottom associated with the valve entire body. It has many diaphragm switches that will tell the pc what gear the particular transmission is in, and the temp sensor is often cooked right into this assembly.
If you have a mid-2000s truck and you're getting shift mistakes along with temp readings that don't make sense, the PSM is a likely candidate. Replacing it isn't much harder when compared to the way replacing a harness, but it's one more reason why knowing the exact allison transmission temp sensor location is dependent slightly on your own specific model year.
Tools You'll Requirement for the Work
If you've decided to deal with this yourself, a person don't need a massive shop, yet some specific equipment can make your living much easier. * The 15mm socket: For the particular drain plug. * The 13mm socket: For the pan bolts. * Rpm Wrench: This is non-negotiable. The pan mounting bolts and the valve body components are made of aluminium. If you over-tighten them, you're going to have a very poor day. * A New Filtration system: Since you're in there, you should definitely change 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, based on what your own manual specifies.
Final Thoughts on the Swap
Dealing with a faulty sensor is annoying, yet it's one of those things that maintains your transmission alive. Without an precise temperature reading, the particular TCM (Transmission Control Module) can't modify the line pressure or shift timing correctly for chilly or hot liquid.
Remember, while the allison transmission temp sensor location is tucked away inside, the task is mostly just the glorified fluid transformation. Take your time, keep every thing surgically clean—transmissions hate dirt—and make certain the new use or sensor keys to press securely into place. Once you've got it back together and topped off along with fresh fluid, your gauge should act again, and your Allison will go back to carrying out what it does best: pulling large loads without splitting a sweat.
If you're still seeing weird psychic readings after an alternative, it's worth looking at the TCM itself, but 9 times from ten, it's either the particular internal sensor or even that big circular plug on the particular outside from the situation. Happy wrenching!