WCFab Transmission Cooler Thermostat Bypass Plug WCF100469

WC Fab Transmission Cooler Thermostat Bypass Plug, 2017-2019 L5P

Part# ‍WCF100469

$59.17

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Fits: 2017 thru 2019 Chevy Silverado/GMC Sierra 2500/3500HD L5P Duramax Diesel

The stock thermostatic bypass for warming up the Allison transmission quickly in cold weather conditions is a good idea in principle, but in practice we've seen the valve fail forcing trans fluid around the cooler in warm weather conditions that causes dangerous fluid temperatures for built and stock transmissions alike. This design has been run on Wehrli Custom Fabrication's shop development trucks and with built transmissions successfully. 

Features:

  • CNC Machined Billet Aluminum Thermostatic Bypass Plug
  • Black Anodized Finish
  • High temperature silicone O-ring seals
  • Great for stock or built transmissions towing heavy in warm climates
  • Reduces fluid flow restriction to trans cooler
  • Experience fluid temperature drops from 15-50 degrees F
  • Direct replacement of the failure prone OEM thermostat
  • Simple installation, easily swap back to OEM setup for cold weather use

Includes:

  • Thermostatic bypass plug
  • O-Ring seals

Customer Reviews

Based on 7 reviews
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Anonymous
Cautiously optimistic

Very happy with it. Doing exactly what it's supposed to. Only concern is in the dead of winter, or a winter like we just had this past season, can the fluid be too cool

A
Anonymous
Brought my temp down by at least by

Brought my temp down by at least by 30

j
jesse hubbell
Trans stays cold

Trans stays cold. Was surprised the difference

J
J Oliver

Finally got around to installing the Werhli bypass thermostat. Installation was a breeze (when you have the proper tools). Temperatures have started to drop here in central Texas so I’ll get a chance to see cold weather functionality over the next few months. I’ll provide an update in about 6 months. Fingers crossed that I don’t have to reinstall the OEM thermostat. Takes longer to remove the air box than anything else.

S
Sean
Works as advertised

Pretty easy, straight forward install. Avg trans temp before were 170-180. Now the trans temps sit at roughly 145 in mid summer desert heat. Temp are cooler on avg towing as well. Good investment for the price.

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