Built to Hold
Build guides, transmission tech, and install notes from the Gearstar shop floor. Every unit we ship is assembled by one builder, matched to your combo, and dyno-tested before it goes out the door. This is where we show the work: what holds, what grenades, and how to spec it right the first time.
Will a 4L60E torque converter fit a 4L65E?
Will a 4L60E torque converter fit a 4L65E transmission? While doable, swapping from an older transmission to a newer or stronger one may call for an...
Turbo 400 vs. 4L80E – Which Transmission Delivers More Power?
The Turbo 400 (TH400) and 4L80E are two powerhouse transmissions, but which one delivers more power? Let’s look at their differences, construction...
How Do I Know if My Transmission Solenoid is Bad?
A bad transmission solenoid can cause delayed or erratic shifting, transmission slipping, or even failure to shift gears. Warning signs include harsh...
Are 4L60E and 4L65E Interchangeable? Understanding the Differences and Compatibility
The 4L60E and 4L65E have many similarities, to the point that some car enthusiasts skip selling and buying a new transmission, and instead learn to...
Can You Drive with a Bad Transmission Valve Body? What You Need to Know
Driving with a bad transmission valve body can cause serious damage to your vehicle’s transmission, harm your driving experience, or even result in avoidable...
TH350 vs. TH400 Performance: Which Transmission Offers Better Power and Reliability?
The TH350 and TH400 are both iconic automatic transmissions built by General Motors, but they cater to different needs. The TH350 is lighter and more...