Introduction to the Laser-Cut Aluminum 66RFE Output Shaft End Play Shim:
When assembling a 66RFE transmission, the plastic (yes plastic) factory output shaft end play shim can be easily broken by so little as a bump of the output shaft. It's a very likely failure point during assembly that few catch as it would only break once the transmission is assembled. Further, they can often break in operation by as much as a rough 2-3 or 4-5 upshift.
We tried using all aftermarket aluminum shims in existence, and none of them cleared out and fit properly. All were either far too tight, causing bearing heat or far too low, causing vibration and bushing wear. We designed the perfect shim, designed for fitment in any 66RFE transmission. Further, we anodized them to protect them from wear over time, ensuring a forever fit. These shims are affordable and quality, and belong in every single 66RFE transmission.