Heavy Duty Bypass Coolant Valve Upgrade Kit For Gm 6L80 6L90 8L90 10L90 Allison Automatic Transmissions Keeps Fluid Flowing Smooth Crushes Heat Soak Direct Fit Swap

Single Pack Heavy Duty Transmission Cooler Bypass Kit
✔️ Steel Bypass Plug Fits GM 6L80 6L90 8L90 Trans 1 Set

This single pack upgrades your stock thermostat valve and drops right into the transmission housing. You get steady coolant circulation whether you are hauling trailer weight or sitting in traffic. The direct bolt pattern skips extra plumbing lines and saves serious garage time.

✅ Constant cooler flow ignores engine temperature swings
✅ Cuts transmission fluid temps and stops heat soak fast
✅ Lets you check fluid levels right after the swap
✅ Solid steel build lasts through seasons of hard use

💡 Why do builders replace thermostat assemblies in heavy duty auto transmissions?

The old valve traps fluid until it hits a set threshold.
You need a fixed route for continuous oil circulation today.
- Steel plug blocks old restriction paths fully
- Moving liquid pulls heat straight to the cooler
- Sealed gaskets hold pressure and stay handy on tough jobs ✝️