The PerformaBuilt Heavy Hauler 4L70E
You are looking at the PerformaBuilt Heavy Hauler Series transmission.
These units are built very similarly to our Pro Race units, but the focus is on durability while maintaining reasonable shift quality. These were specifically developed for commercial, heavy towing, and 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 staked bushings, 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 second and fourth 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 without the excessively harsh shifts associated with the aftermarket “super servos.”
For Fourth (OD), we use the Sonnax Dual Piston servo. This servo has 30 percent 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 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 BEAST. 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 Heavy Hauler Series uses 4 pinion planetaries.
For the Heavy Hauler Transmissions, we only use the thicker “K” cases that came in the very high performance cars and 4×4 trucks. You won’t have to worry about cracked bell housings and cases.
Lastly, we address the valve body. Here we perform all the updates for lube and durability, and eliminate the partial lockup function 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 hold 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! And, since we know you need your truck, handling time is 4 days or less in most instances. Shipping can be to your residence or any business address with no additional charge. 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.