If you’re a Duramax diesel enthusiast or truck owner, you’re likely familiar with the Allison 1000 transmission. Revered for its durability, smooth shifting, and ability to handle the power of diesel engines like the GM Duramax, it’s a popular choice in heavy-duty trucks. However, even the best transmissions aren’t immune to problems. In this detailed guide, we’ll combine insights on diagnosing common issues, troubleshooting tips, and upgrading your Allison transmission to ensure your truck keeps running strong under any condition.

The Allison 1000 transmission has long been a cornerstone of GM’s HD truck lineup, particularly in conjunction with the Duramax engines. Over the years, this transmission has undergone continuous refinements to meet the evolving demands of power, performance, and emissions standards. In this post, we'll break down how the Allison 1000 transmission has evolved across six generations of the Duramax engine family: LB7, LLY, LBZ, LMM, LML, and L5P, highlighting key changes and comparing performance across each year range.

Diesel engines have many nuances when compared to their gas counterparts, fuel injectors being one of them. Unlike fuel injectors used on direct injection gasoline engines, diesel injectors often have a higher failure rate and shorter lifespan due to their more extreme operating conditions. When these injectors fail, it can lead to a cascade of performance issues, increased emissions issues, and even engine damage.

Diesel engines are renowned for their power and efficiency, but they also come with complex emission systems designed to reduce harmful pollutants. Two critical components of these systems are the Exhaust Gas Recirculation (EGR) valve and the Diesel Particulate Filter (DPF). When these components fail, it can lead to decreased performance, increased emissions, and costly repairs. Understanding the common causes of EGR and DPF failure can help you maintain your diesel engine in top condition. Here are the top three causes of failure for each component:

Adding power to your diesel, whether it be a  Cummins, Powerstroke, or Duramax, can be a fun and rewarding experience. However, when it comes to upgrading an emissions in-tact truck options can sometimes be limited and results can often be underwhelming. But that doesn't mean you have to suffer with poor performance, complicated upgrades or the cost of removing your emissions components! Emissions in-tact custom tuning is a solution that will not only blow you away in terms of performance and ease of installation but it can also improve the performance gains from other aftermarket upgrades that may not be pulling their weight as they stand.

Unleashing Hidden Potential Without Compromising Emissions

Emissions In-Tact Custom Tuning is specifically designed to optimize the performance of your diesel truck while keeping all emissions systems fully operational. This means you can enjoy improved power, torque, and fuel efficiency without the need to remove or tamper with your truck’s emissions equipment.

As the winter months rolls around us diesel owners get an unexpected bit of stress added to our plate. Diesel fuel gelling is a very common issue most diesel owners who live in areas where the temperature drops below 32 degrees will face at least once in their lives. Not only is this issue frustrating and stressful when it occurs, the mere trauma from past experiences can lead to constant stress during these cold times. No one wants to get out of work in the pitch black freezing cold only to find that their truck won't start at all. But what should you do in the event that your truck won't start or stay running? Luckily we have a step by step guide on how to properly fix this issue once it has occurred. 

As a preface, this issue is caused when the paraffin wax used in diesel fuels (for lubricity and proper viscosity) start to solidify.  While gelling can take on varying levels of severity from cloudy fuel all the way to a squishy solid mass. Diesel fuel gelling is never a thing you want to expeirince. At its most mild levels it can cause poorer fuel economy, less power, and be pretty hard on your fuel system. At its worst I can clog fuel lines, filters, pumps and even injectors while potentially causing irreversible damage to your fuel system.  If you live in a cold climate take precautions by adding anti-gelling agent into your fuel before severely cold temperatures start setting in to avoid all of these issues. 

Over the years, GM has changed a lot regarding the turbos they use on Duramax engines. Not only have they changed manufacturers a handful of times but each RPO has its own unique measurements for key components. This can make it a headache when trying to track down exactly what the measurements of your stock turbo are. Luckily we've compiled this list of stock Duramax turbo specifications along with other helpful information so you can get a good idea of what you're already working with before you dive into the sea of turbo upgrades these trucks have to choose from. However, while some turbos may have the same peak power output, the size and shape of specific components can affect things such as exhaust gas temperature, drive pressure, and turbo efficiency range.  

The ten-speed Allison 1000 is substantially better than previous Allison models we have seen come in Duramax trucks. Known for its superior towing performance, excellent fuel economy, and outstanding reliability. It utilizes some of the best technology GM has ever produced. Its reputation for excellence was earned largely because of the advanced electronic control systems provided by the TCM (Transmission Control Module).

One of the biggest advancements in turbo design since we first started applying them to diesel engines over 70 years ago has been the invention of Variable Geometry Turbos. These turbos utilize a set of movable vanes on the inside of the exhaust housing that allows the actuator to vary the area in which exhaust gasses can pass through them. This allows the exhaust side of the turbo to increase or restrict the flow of exhaust hitting the turbine wheel. In some designs it also changes the flow direction of gasses hitting the exhaust turbine as you can see illustrated below. 


When restricted, the velocity of the exhaust gasses increases which helps spin the turbine faster than a fixed geometry turbo would. This gives the turbo the ability to spool the turbine and compressor wheel up much better than it normally would even with a low volume of exhaust pressure traveling through the system. This helps to spool the turbo at lower RPMs to create boost where it would normally be lacking. This is why variable geometry turbos (VGTs) are such an advancement. They have the ability to significantly reduce turbo lag and provide much better response and turbo efficiency across a range of RPMs.