January 29, 2020
The OE case bushing in vehicles with a GM THM-400, 4L80-E and 4L85-E transmissions tends to walk out of the housing bore. This leaves the output shaft unsupported, ruins the governor gear and can cause case damage. The no-walk flange feature of the Sonnax case bushing 34006-SP is specially designed to keep the bushing in the case bore.
The housing bore should not measure more than 2.1285" in diameter for an ideal fit.