PPE 125065020 Transmission Fluid Thermal Bypass Valve (2017-2019 6.6L Duramax)

Fitment

This valve is listed for the L5P 6.6L Duramax in 2017-2019 Chevrolet Silverado 2500HD, Silverado 3500HD (single and dual rear wheel), GMC Sierra 2500HD and Sierra 3500HD (single and dual rear wheel). Our catalog tags it for the L5P, which runs from 2017 to current, but PPE's title limits this part number to 2017-2019 trucks, so verify fitment by VIN. If you have a 2020 or newer L5P, don't assume it fits. Send us your VIN or call the shop and we'll check it before you order. Browse more Duramax parts for your truck.

Why this part

The factory thermal bypass valve works like a thermostat that controls fluid flow to the transmission cooler, and it has restrictive internal passages. When the OEM valve fails in the closed position, transmission fluid doesn't reach your cooler. Mechanical failure or debris can cause it. The result of a stock valve failure can be a transmission that dangerously overheats.

Without properly cooled transmission fluid, the demands of towing and rigorous stop-and-go driving shorten the life of transmission components. The PPE bypass valve eliminates the extremely restrictive mechanical factory valve and maximizes fluid flow to and from the transmission cooler. It feeds 100% of the fluid through the front-mounted coolers, and it flows more than the factory thermostat does even when that thermostat is fully open. You get more cooling capacity, and you take a known failure point out of the cooling circuit.

PPE added another measure of protection, too. The service plug carries a neodymium magnet and seals with an O-ring. The magnet traps ferrous debris, and you can pull the plug to remove those particles from the system. The factory bypass valve does not have this feature.

What you get

• PPE 125065020 billet aluminum transmission fluid thermal bypass valve
• Neodymium magnet equipped service plug with O-ring seal

Specifications

PPE's feature list for this valve:

• Feed 100% of the transmission fluid through the front-mounted transmission coolers
• Neodymium magnet equipped service plug removes metal particles
• Increased flow compared to the factory-restrictive thermostat even when it’s fully opened
• Billet aluminum construction
• Easy bolt-on installation

Installation notes

PPE rates this as an easy bolt-on installation in place of the factory valve. After it's in, the magnetic service plug stays accessible, so you can pull it at service time and clear out whatever metal particles the magnet has caught.

About Pacific Performance Engineering

Pacific Performance Engineering (PPE) started in 1985 and is based in North Las Vegas, Nevada. The company made its name on 6.6L Duramax parts before branching out into Ram Cummins and Ford Powerstroke trucks. Its line covers transmission, exhaust, fuel system, cooling and steering parts, plus cast aluminum pans and covers.

Frequently asked questions

What happens if the factory bypass valve sticks closed?

Transmission fluid stops reaching the cooler. Debris or a mechanical failure can cause it, and the result can be a dangerously overheated transmission, especially when you're towing or stuck in stop-and-go traffic. The PPE valve removes that restriction and feeds 100% of the fluid through the front-mounted coolers.

What does the magnet in the service plug do?

The neodymium magnet traps ferrous debris circulating in the fluid. The plug seals with an O-ring and can be removed so you can clean the particles out. The factory valve has no magnet.

Will this fit my 2020 or newer Duramax?

This part number is listed for 2017-2019 L5P trucks. For a 2020 or newer truck, call the shop or send us your VIN and we'll tell you what fits before you buy.

Questions on fitment? Call the shop at the number in the header. We install everything we sell.