Rebuilds & Upgrades
How Long Does a Transmission Last? Mileage Is the Wrong Number
A healthy automatic in a stock car runs 150,000 to 250,000 miles. Behind a built engine, that number stops predicting anything, because the loads that...
Rebuilt, Remanufactured, or Built: Three Words the Industry Uses Loosely
Ask three shops for a transmission quote and you might get three very different numbers, all for something called a "rebuilt" transmission. One is a...
700R4 vs 4L60E: What To Know Before Upgrading
When it comes to GM overdrive automatics, few transmissions get talked about more than the 700R4 and the 4L60E. Both have proven themselves in everything...
4L70E vs 4L60E: Specs, Internals, and Which One Your Build Actually Needs
The 4L60E and the 4L70E share gear ratios, a valve body layout that looks familiar, the same case family, and the same overdrive operation. Externally...
4L80E Upgrades: Top Performance Parts to Boost Your Transmission
Discover essential 4L80E upgrades, including the Gearstar Billet Direct Drum with oversized sprag, 300M input and main shafts, and supporting components....
Essential 6L90 Transmission Upgrades
If there’s one thing GM got right with the 6L90 transmission, it’s that they built it to survive real work. Found behind heavy-duty trucks, performance...
4R70W Transmission Controller Explained
This guide explains the 4R70W transmission controller, the electronic brain that commands shifts and lockup. Learn why factory computer control fails for...