Our tech team would be happy to help you directly. They can be reached via email at sonnaxtechsupport@sonnax.com, or phone at (800) 843-2600 ext. 398. Thanks for reaching out!

This is a 4WD output shaft, also. Another thing.. where the case bushing (7) is pressed into the bore, there are two oil passages that are mostly covered by the bushing, at the notch positions, and definitely allow oil to pass into the after-section, case extension (6-bolt, for the 4wd adapter to the t-case). Why in the world would anyone want ATF to pass into the extension adapter for the 4WD application ? The oil is just pooled in this area, cannot, obviously enter the t-case, due to input shaft seal, and there is no drain-back holes into the transmission body. When I loosened the adapter nuts to take down the unit, ATF poured out of this volume, and, of course, on the 4L60E, there is no case rear seal, as in the 4L80. So, what is the purpose of these two oil passages that trench under the case rear bushing ?

@@boogerhead0 Our tech team would be happy to help you. They can be reached directly via email at sonnaxtechsupport@sonnax.com, or phone at (800) 843-2600 ext. 398. Thanks for reaching out!

Hello, we recommend checking with Transtar. If you need any additional help, feel free to reach us via email at info@sonnax.com, or phone at (800) 843-2600 or +1 (802) 463-9722. Thank you, and have a great day!

@@sonnax thanks

Spline twist is a factor of four variables: power, weight, traction and firmness of shifts. Generally speaking, this part becomes a liability at 650HP -750HP. Thanks for your question, and have a great day!

@@sonnax thanks for the reply this was very helpful 👍

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