This causes many failed Allison Transmissions to sneak up on DuraMax owners with actively functioning Allisons. Here's a guide on what could be causing the issue and how to fix it. It shifts based on three input: 1. Loss of acceleration. An Allison Automatic uses the full torque from the engine and multiplies it with the torque converter. Some transmissions are considered adaptive in that they are consistently learning and adjusting to your driving patterns. The source of this problem could be obstacles building up in the governor, modulator, or valve body passages. However, if that doesnt work, you will need to have the vital transmission parts looked at. However, if you see dark spots on the surface where your motorhome is parked, you could well be dealing with a leaky transmission fluid reservoir. Transmission Fluid The hard shifting problem is often linked with low transmission fluid levels. It should have all the products that the company has in stock. Its notoriously thin and flimsy, often cracking during anything that generates high internal converter pressure, such as towing, hills or high performance. Allison is not with GM anymore and hasnt been for about 15 years. The High Pressure Oil Pump- may get too many clutch and steel particulates inside of it. Allison transmissions built in the mid-2000s had a recall issued for their TCM module. Another reason for the Allison Transmission system to give you shifting problems can be that it is heating up. 7. Sensors can become damaged because of old age, an electrical short, or excessive temperatures. You can also keep the engine running when checking it. In some cases, its caused by a clutch with an uneven surface. Reproduction in whole or in part without permission is prohibited. If it feels like it is shifting toward the engine red line you could have it hooked to the wrong port. It should help you in filling the fuel and closing off the bolts correctly. You can then check for any leaks to ensure the fuel has been replaced correctly. So, if the transmission fluid has turned dark brown, consider flushing it out and adding fresh fluid. Our goal is to facilitate superior shift feel without conflicting with Allisons adaptivity protocol. Here are a few potential fixes! Save my name, email, and website in this browser for the next time I comment. Sometimes the simplest things are overlooked or not known to be looked at. On a recent trip to the lower peninsula of Michigan, we were approaching the Big Mack Bridge from the west, and I noted a very hard down shift of the transmission in the last couple of miles before the bridge. Fuel filters do cause shifting problems and is most likely the cause of your problems. This mode is triggered by anything that could cause severe damage to the transmission, including severe overheating or towing a very heavy load. It would take a day or two then the check engine light would go away. Make sure that you check for supportability beforehand to ensure you dont run into any issues afterward. We were confident wed found the problem and could help the customer out with a repair. the way the Allison shifts with increasing speed (when in normal mode, not tow/haul), is to go 1st gear, 2nd gear, 3rd gear, 4th gear, 5th gear, then like 5 mph/couple seconds later after the 4-5 shift, the converter locks up and stays locked all the time in 5th gear until your speed drops below 45mph. Allison valve bodies are notorious for one problem in specific, valve seizure. This discussion is proudly sponsored by: Please support our sponsors and let them know you heard about their products on iRV2 Thread Tools Join the #1 RV Forum Today - It's Totally Free! After all, GM owned Allison for decades before they sold part of the unit back in 2007. Update your browser to view this website correctly. In the Allison 1000 Transmission, this is C2. Powertrain Expo One of the most common signs of a bad speed sensor is abnormal automatic transmission operation. 5. At Next Gen, we have spent years developing Allison transmissions that offer incredible longevity, stunning performance and staunch capability. CamperUpgrade.com is a participant of the Amazon Services LLC Associates Program, an affiliate advertising program it is designed to provide an aid for the websites in earning an advertisement fee by means of advertising and linking to Amazon.com products. I wasn't worried much about this at first until another problem started happening. It was announced in 2019, that the 2020 Sierras and Silverados would be coming out with this transmission option. The OEM Allison 1000 Transmissions C2 hub is a large failure point in this specific unit. You should check them immediately. The Allison 1000 Input Shaft is large and solid, but does incorporate an oil circuit in the middle in 2011. You might see this show up most commonly when shifting between first and second gear. Symptoms of a bad valve body present as sloppier shifts than when the truck was new, or being quick to downshift under load. Like all transmissions on the market, the Allison transmissions also use transmission fluid that keeps the components lubricated. Now it happened again last week and it wont move at all and the D just flashes. The gears should last for the lifetime of the transmission, but hard shifting is a sign that something might be wrong. He stated his only reservations depend on how long it had been driven like this, might have resulted in damage to the clutches. Many shift abnormalities involve the transmission shift controller's numerous valving operations, which utilize accumulators, solenoids, pistons, and piston shafts. For the most part, this transmission seems to be very reliable. The oil also helps in keeping the device healthy and should prevent most problems with it. TSB 04-07-30-018A - Ice buildup on shift cable - Allison 1000 Transmission 2001-2006 Chevrolet Silverado 2500HD - 2001-2006 GMC Sierra 2500HD Problem - In cold climates, it may not be possible to shift the transmission after operating it in snow, slush, or icy conditions. It is coupled with the Duramax diesel engine and that seems to be the perfect partnership. Throttle position that is an input via the modulator circuit. The best thing to do is take a more recent GM truck with this transmission out for a test drive and see for yourself. Allison was a GM company for decades so this new transmission should still be good even though GM spun it off recently. For heavy towing, or added power, a CNC Machined Billet Steel input shaft is imperative. The problem still exists and the transmission shop does not know how to proceed. That does not stop GM from building top transmissions for its trucks. Therefore, it would be a good idea to refer to the operator manual to know about the model-specific information if you cannot find the dipstick. We won't send you spam. The Stator- this is the part that controls the stall speed and it is not very strong. Should have done that maaaany kms ago. Now connect them back in carefully and your issue should now be gone. A loose valve spring adjustment or stuck modulator valve causes problems during low and rough shifting. In fact, when we cut the converter apart to begin manufacturing our popular Allison Torque Converters, we often see 6 distinct burn spots over the pads of the cover where the bolts thread in. Unsubscribe at any time. Later, in 2006.5 when the LBZ DuraMax was introduced, came the 6th gear accessible Allison 1000 Transmission. This will also help you in selecting a product that will best suit your usage. Given the power many modern motors come with, there are limits to what the 10-speed Allison can handle. . A broken reaction carrier could prevent the transmission from. The operational tenure of the Allison 1000 Series transmission was ultimately from Model Year 2001 to Model Year 2019. Dealer service writer and other mechanics state problem is very common and part should be recalled. A Logic Diagnostic Process for an Intermittent Temperature-Related Shift Problem, In a Sticky Spot An 09D Ratio Code Problem, Computer hardware or software malfunctions, Circuit leaks that wed check, with other testing. The installation procedure should be given along with the equipment. If you are still unable to figure out what might be wrong with the connection. Allison and GM have been together for so long it is hard to think of them being two separate companies now. This isnt an easy part to get to. We were confident that it was not a computer issue, and that it was time to do further inspection. It is a good upgrade that should help you tow over those mountain roads a lot better than you had in the past. Now it has developed losing the indicator under the cluster for drive on the dash and can happen while driving once that happens the tranny doesnt shift and starts to heat up. Fortunately, the scan tool we were using provided actual and desired amperage (figure 2). Until the transmission reaches its normal operating temperature, the operation could be rougher than normal. I have a 2018 GM duramax 6 spd.trans that appears to shift in to too high of a gear [like trying to starts a standard trans in 4th]. I would not tamper with too much as you probably have a lot of weak parts in the Alli. With all of these complaints and problems, the review still states that this is a long awaited upgrade. If it's shifting to early and bogging, you may have it in the wrong port. The Allison also only features one incredibly thin clutch from the factory. Allison Transmission is an American company that is mainly known for its transmission systems. 6 Signs Of Low Transmission Fluid And How To Check the Level, 5 Symptoms Of A Bad Transmission Cooler and Replacement Cost, 6 Symptoms Of A Bad Transmission Control Module (TCM), 5 Symptoms Of A Bad Transmission Mount and Replacement Cost, Transmission Fluid Leak When Parked - Causes And Fixes, Car Wont Accelerate But RPMs Go Up: Causes & Fixes. A large part of Allisons adaptivity protocol is complying with stringent EPA regulations regarding efficiency, and maintaining lower RPMs and engine loads has a positive correlation on emissions control. We decided to check the computers' ability to properly operate the trim solenoids first. 4. Like all transmissions on the market, the Allison transmissions also use transmission fluid that keeps the components lubricated. A dipstick is usually used for this purpose. If yours appears to have never been replaced, your best bet is to contact the manufacturer and ask about the replacement process. A forum community dedicated to Chevrolet and GMC diesel truck owners and enthusiasts. The alternative that resolves this is a billet steel P2 carrier, it is at about 800HP where these begin to fail, but we have also witnessed these failures in ultra-heavy towing applications. Therefore, a failing speed sensor will have a direct impact on automatic transmission operation. Trim solenoid A and B work together to control the quality of each shift. The good news is that the new 10-speed transmission may have been designed by top engineers who stayed at GM when they sold Allison to another company. The clutch pedal can also become stiff, making it hard to shift when the time is right. Which would be causing those pistons that direct the flow from your 2nd and 3rd rail to be sticking and keep it in second. You should only be putting 15000 miles max on the fuel filter. The vehicle has experienced torque converter shudder since the purchase date of 06/28/2016. Coinciding with the previous 2 problems, is the clutch pack associated with them. However, it could be a u-joint. You can do this by leaving the trans in nuetral (set the e-brake of course). A forum community dedicated to Chevy and GMC Duramax diesel owners and enthusiasts. Cart It is for this that many Allison 1000 Transmission owners report that it will often shift just fine up until its final moments. 8. The 10-speed Allison is no exception. At the time, and currently, General Motors owns a considerable portion of Allison, and was able to use the coveted Allison transmission in their trucks at a market-competitive cost. The issue with this is that it presents many places where the valve can hang up on a valve bore. New Member. Our next step was to let the vehicle sit overnight to cool off, and then drive it and monitor everything when it was working properly. Introduction to the Allison 1000 Transmission: When we build our coveted and durable Allison transmissions and rebuild kits, each one is designed to never return broken. Line pressure was good, no codes have been set in any system, and no abnormalities with any sensors on the scan tool. After the repair, the trim A valve held 22 hg of vacuum. Although the transmissions manufactured by Allison are quite durable, you may run into a few issues sometimes. You can reset the 4-5 shift adapt by it self with a Tech 2. 6.4 Hemi vs 6.2 Ford- Which One Is Better? Oh yeah , change the filter, i change mine every other oil change on both trucks, thats 7 k on mine and 10 k on the wifes! would that cause it to lock up only when shifting at higher gears? The Allison 1000s bushings are made from a weak babbitt material from the OEM. The valve itself can also go bad. There could be many reasons for this problem that we have mentioned in this article.