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Wehrli

Wehrli 17-19 L5P Duramax Billet Anodized Transmission Cooler Thermostat Bypass Plug

4.7 store rating · 572 reviews
SKU: WCFWCF100469

Fits 2015 Cadillac Escalade, 2014–2018 Chevrolet Silverado 1500 and more · Duramax

All 47 applications
$64.99
Ships in 1–2 business days.
9600 Entries150X
This purchase enters you to win FSD26, a 2024 F-350 Limited and $20,000 cash. See the truck · No purchase necessary
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  • 30-day returnsSee the return policy
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As a direct replacement for the failure prone OEM thermostat, the Transmission Cooler Thermostat Bypass Plug can drop fluid temperature from 15-50 degrees F by reducing fluid flow restriction to the trans cooler. In the stock application, we've seen the valve fail forcing trans fluid around the cooler in warm weather conditions that cause dangerous fluid temperatures for built and stock transmissions alike. - - Recommended for trucks with stock or built transmissions and performing heavy towing in warm climates to help keep fluid temperatures in check. - - The WCFab Transmission Cooler Thermostat Bypass Plug is a quick and easy install and will work with the following range of GM vehicles equipped with a factory installed transmission cooler thermostat bypass (6L80, 6L90, 8L90): - - 2017-2019 Chevrolet Silverado & GMC Sierra 2500HD/3500HD with 6.6L Duramax Diesel - 2014-2018 Chevrolet Silverado & GMC Sierra 1500 with 4.3L 6 Cyl, 5.3L 8 Cyl, and 6.2L 8 Cyl Gas Engines - 2015-2020 Chevrolet Suburban, Tahoe & GMC Yukon with 5.3L 8 Cyl, and 6.2L 8 Cyl Gas Engines - 2015 Cadillac Escalade with 6.2L 8 Cyl Gas Engine

  • Experience fluid temperature drops from 15-50 degrees F
  • Direct replacement of the failure prone OEM thermostat
  • CNC Machined Billet Aluminum Thermostatic Bypass Plug
  • Easy swap back to OEM setup for cold weather use
  • Reduces fluid flow restriction to trans cooler
  • High temperature silicone O-ring seals
  • Black Anodized Finish
  • Simple Installation

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Good to know

Questions, answered straight.

If it is not here, call or text the counter. Real people, real answers.

Fitment

  • Will this fit my truck?

    The Fits section at the top of the page lists the manufacturer's applications for this exact part. If your year, make and model is not there, or you are not sure, text us a photo of what you are replacing with your year and engine and we will confirm it before you order.

  • What if I order the wrong part?

    Call or text us before it ships and we will swap it. After delivery you have 30 days to return it in new, uninstalled condition. The return policy has the restocking details.

Shipping

  • When will it ship?

    In-stock parts usually ship within 1 to 2 business days from warehouses across the USA. The stock line under the options tells you the status of the part you are looking at. Large items ship LTL freight and we call to schedule delivery.

  • Why did I only get part of my order?

    We ship from multiple warehouses, so an order with several items can arrive in more than one box. Tracking for each shipment is emailed as it goes out. Full details in the shipping policy.

Returns and warranty

  • What is the return policy?

    30 days from delivery, in new and uninstalled condition, with a restocking fee. Everything is spelled out in the Returns & Refund Policy.

  • How do warranty claims work?

    We are an authorized dealer, so the manufacturer's warranty applies to every part we sell. Call or text us with your order number and we handle the claim with the brand for you.

Paying

  • Can I pay over time?

    Yes. Shop Pay installments are offered at checkout on qualifying orders, and the monthly estimate shows right under the price.

  • What is a core deposit?

    Some remanufactured parts, like injectors and turbos, carry a refundable core deposit. It is shown on the product page when it applies and refunded when your old part comes back to us.

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Why buy here

A diesel shop that sells parts, not a website that sells boxes.

Every part on this site is one our own techs can stand behind.

  • We run what we sell

    A working diesel repair and fabrication shop in Nazareth, PA. These are the parts our techs install every week.

  • Real techs on the phone

    Call or text 908-223-9744 and you get a diesel tech, not a script.

  • Authorized dealer

    Genuine parts straight from the manufacturer, with the factory warranty behind them.

  • Fast from stock

    Most in-stock parts ship in 1 to 2 business days from warehouses across the USA.

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Full Send Diesel, Nazareth, PA

A team of diesel people, not a call center.

Full Send Diesel is a shop full of techs, builders and parts people in Nazareth, Pennsylvania. When you call or text, you reach someone who works on these trucks and knows the parts.

Not sure what you need? Send a photo of what you are replacing with your year and engine. We will point you to the right part, confirm it is in stock, and get it moving.

Call 908-223-9744 Text us Email

Mon–Fri, 8am–4pm ET. After hours, text or email and we answer first thing in the morning.

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