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.
Ultimate 700R4 Rebuild Kit Guide
"What 700R4 rebuild kit is right for me?" This is the question of a prospective rebuilder searching for the best 700R4 rebuild kit on the market. The 700R4...
6L90E Transmission Specs and Identification
The 6L90E is a high-performance component suitable for handling as much as 700 horsepower. This 6-speed automatic transmission built by General Motors...
E4OD Transmission Upgrades for Heavy-Duty Towing and Off-Roading
The E4OD transmission developed by Ford is a heavy-duty unit generally found in the Bronco, E-series vans, Expedition, and F-series trucks. This is a...
4L80 Torque Converter Basics for Reinforcing Speed and Drivability
There was a time when drivability, low emissions, and high horsepower were topics of discussion and disputes. Nowadays, auto-shift cars feature speed, fuel...
An Overdrive Transmission Is Awesome, Just Misunderstood
When the automatic transmission first appeared on the market in the 1920s, anyone could count the number of gears on just one hand. But today,...
Qualities of a Bulletproof 4R100 Transmission
The first electronically-controlled transmission from Ford was introduced in 1989 and named the E4OD (E = electronically controlled; 4 = Forward Gears;...