Suncoast PLSD-46RH-4X 4WD Transmission | 89-93 Dodge 5.9L Cummins

(No reviews yet) Write a Review

Suncoast PLSD-46RH-4X 4WD Transmission | 89-93 Dodge 5.9L Cummins


Warning: This product can expose you to chemicals that are known to the State of California to cause cancer. For more information, visit

For over two decades SunCoast has continually led the industry in both innovation and performance. Dating back to the days of Redneck Nationals and Team Green before outlaw racing was even thought of SunCoast transmissions were breaking records and winning world championships. The phrase "copied but never caught" could never be truer than now.  Each one of our Dodge Torqueflite transmissions receives what we call our base packages. This base package can be built and improved upon with a plethora of options and upgrades to suit your individual needs. These units are not "cookie cutter" units but rather something individually catered to your specific needs. Each one of our calibrations to the valve body, pump, separator plate, and even the clutch stack-ups are meant with your intended usage in mind. These units include having many upgrades from the factory not just for performance but restoring hydraulic integrity to some very crucial circuits,

The Torqueflight transmission utilizes a band to shift the transmission into 2nd gear, then this band is released when shifting into 3rd gear. This band is wrapped around the direct drum (right behind the transmission pump)this drum house the direct clutches (3rd gear). When thinking about the amount of torque these trucks can make coupled with the torque multiplication of the converter and it soon becomes apparent why this area could be problematic. The band itself from the factory is a very flexible band, these band will stretch and require constant adjustment. When even modest attempts of increased apply pressure occur these band break due to the flimsy construction. You will some aftermarket attempt to use a very rigid material to keep these from flexing or breaking. SunCoast took a different approach and just redesigned the band altogether. Each one of our units receives a new SunCoast custom billet band machined in house. This new SunCoast billet band is also lined with a Carbon Fiber friction material offering the best friction coefficient available.
Our next focus is with the hydraulic integrity of this band actuation. The best band in the world is useless without proper clamping force when applying and a quick release off the drum when needed. This is where our SunCoast billet 2nd gear servo comes into play. The factory uses a cast servo, the servo offers two simple O-rings to help control cross-leaking within the bore. This bore over time will wear, as it wears cross leaking occurs causing lazy shifts, slips going into 2nd gear, and of course in some events bind-ups and dragging of the band going into 3rd. SunCoast corrects this by installing a custom CNC billet intermediate servo. This servo is made with 4 sealing rings both Teflon and rubber, That is double what the factory uses. This servo is also larger in the application area, over 20% larger than the factory. This larger apply surface area allows for not only a dramatic increase in apply pressure giving you an enormous amount of clamping load, but this also allows for a faster shift time. As almost everyone in our industry lust over the additional clamping force and much quicker applies to time, we often overlook the release of the band. The release of the band can be just as an import if not more. When they drag on release it can cause bind-up issues, scoring of the band material, and of course premature wear. SunCoast also modifies the length of this servo to achieve much crisper shifting.
Now that we have increased the clamping force we must address the two other problematic issues with the band strut and the band anchor. Just as an engine builder would change to a stronger chrome moly push rod when changing the camshaft to ensure no deflection occurs the same can be said for the band strut and band anchor. With now having a more apply pressure on the band we must correct or issue with the factory band strut as well. SunCoast replaces the factory band strut with a much stronger billet band strut to keep any deflection at bay. The band anchor is also replaced with a billet one as well.

Customers Also Viewed

Need help? We're available at208.719.7400 - Email us orlive help
to top