The PerformaBuilt Extreme 4X4 4L70E
This Transmission has a Core Charge
Our Extreme 4X4 Series is ideal for rock and mud crawling. This series is very similar to our Heavy Hauler, except it’s built with climbing and spinning in mind. It has slightly more aggressive shifts and more punch built in. It is ready to head to the mountains or play in the bog – your choice.
These units are built very similar to our Pro Race units, but the focus is on durability while maintaining reasonable shift quality. These were specifically developed for 4×4 vehicles. The shifts on these units are designed to take the abuse and work associated with these vehicles, but without the tire chirping shifts of our race and performance units.
These units feature a heavy duty 13-vane pump with full-time lube modification to keep the heat down, and a modified lockup valve to improve the lockup converter’s durability so you can tow confidently in overdrive.
We use a heavy duty wide band for maximum hold in 2nd and 4th gear. To compliment this, we use the Corvette servo. This servo is the largest servo available from GM. It will supply the clamping force needed for these heavy units but without the excessively harsh shifts associated with the aftermarket “super servos.”
For Fourth (OD), we use the our Proprietary Performance Overdrive servo. This servo has more holding force than the stock overdrive servo. That, accompanied with the 20 percent wider band, will let you tow in overdrive with confidence. Now you have nearly double the load capabilities of the stock transmission in overdrive.
We use Alto High Energy carbon composite friction plates in the forward clutch set. These clutches have an outstanding friction coefficient for maximum holding. They have superior temperature capabilities and they don’t burn easily, even in the worst conditions. This is important because the clutch has to bear the load in every gear except reverse.
For the 3-4 clutch, we use 8 heavy duty friction and steel plates. More friction plates than stock; which is 6 in most cars and trucks. Some additional modifications to the 3-4 set and this clutch pack prevent scoring and burning and increase hold.
We next attack a weak link, the sun shell. In particularly heavy vehicles, vehicles used for heavy loads, and those used for off-roading, constant shifting occurs from first to second and reverse. To address this, we use only the GFX Shell. These sun shells do not break. They are almost twice as thick as a hardened or new OEM shell and they have a reinforced collar. You will not have to worry about that sudden loss of reverse, 2nd, and 4th gears associated with the breakage of this piece.
Moving on, in the planetary, both sun gears are modified to increase lube flow. This is a must in these heavy duty units. A lack of lube and cooling is a killer when pulling the boat, camper, or work trailer loaded down with equipment. The Extreme 4X4 Series uses 4 pinion planetaries.
Lastly, we address the valve body. Here we perform all the updates for lube and durability, and eliminate the partial lockup function, found in the 4L60E. This greatly extends the converter life and helps to keep everything much cooler. We improve the flow to the 3-4 clutch set, making sure it has enough supply to help ensure that it holds the load on this crucial shift. We enlarge the apply release feeds for the lockup clutch to make it apply positively and avoid converter clutch burn-up under heavy load. Finally, we include a low stall heavy duty carbon composite lockup clutch torque converter.
As with all our units shipping is free within the mainland USA and there is no core charge on all 60 & 65 units. This unit comes with our PerformaBuilt warranty for 2 years regardless of the miles you drive! If it dies, you simply return it, we repair it or replace it, and return it to you within days, not weeks. Warranty is limited to repair of the transmission at our facility. We are not responsible for any other loss incurred, such as wages, R&I cost or any other loss.