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Upgrading GM 4L70E Transmissions Via Gearstar

Gearstar performance transmissions are all custom. Building each transmission with to the specific needs of the customer is important to Gearstar. We’re looking to maintain a standard of excellence in the industry.

Gearstar 4L70E Transmission while you work

Upgrading GM 4L70E Transmissions Via Gearstar is promising. Rated for up to 650 hp and 650 lb-ft of torque makes the Gearstar 4L70E transmission a perfect upgrade solution. Read full specs for the Gearstar 4L70E Level Two Here.

Gearstar Performance Transmissions while you sleep

The 4L70E

During our chat with Mark Walk of Gearstar Performance Transmissions in Akron, Ohio, we learned a lot about these time-proven GM overdrive automatics. These are well engineered transmissions from the factory, however Gearstar knows how to make them better. “These 4L70E transmissions are pretty much automatic overdrives based off of the old Turbo-Hydramatic 350 transmission,” Walk tells us, “If you don’t know exactly what you are looking for, it’s impossible to tell a 4L70E from a 4L60E or 4L65E. There aren’t any physical differences externally in the case, furthermore, even the cases are still stamped 4L60E.”

Gearstar Performance Transmissions while you ride

The Gearstar 4L70E

First, each Gearstar 4L70E is custom built to order and engineered to perform. Raybestos Gen II clutches provide transmission blueprinting. Also heavy-duty steels and TransGo shift improvement kit. Finally, new high-performance hard parts throughout.

“When exceeding the factory ratings of around 450 horsepower and up, you’re going to need some improved performance components in the 4L70E transmission. Those improvement are determined by power, torque, and in addition what you’ll be using the car for.  The 4L65E Level II, is our entry level high-performance transmission and it starts at 450 horsepower and 425 pound feet of torque. Consequently, at that point is when you need to start entertaining something that can handle more power.”

The 4L70E is a vastly improved version of the 4L60E. However, Walk tells us there’s room for improvement so your 4L70E will last under demanding conditions. While most people want a smooth shift, smooth shifts happen due to slippage, as a result, slippage creates heat. Heat sheds clutch/band friction material in the fluid, which damages seals. You want a firm upshift while having a smooth, unnoticeable downshift. Additionally, upgrading the friction materials in a 4L70E can go a long way in improving it’s durability and power rating. Moreover, GM’s E model automatic overdrives are more versatile and intelligent transmissions. The driver can have direct control of shift timing, wide open throttle up shifts, torque converter lock up apply, and at what MPH this takes place.


The GM 4L70E transmission is a stout and healthy unit in stock form. We’ve shown you how it is a big improvement from the more common 4L60E and 4L65E. A few improvements in hard parts friction materials and the 4L70E can easily stand it’s ground.  Managing the type of power that today’s engines are capable of producing while maintaining the benefits of overdrive and electronic shift control.


Source: Upgrading The GM 4L70E Transmissions With Gearstar – Chevy Hardcore

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