The OE case bushing in vehicles with a GM TH400, 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. High-quality bronze Flange on the transmission case side prevents bushing from walking completely through the bore Flange accurately locates and helps retain the selective washer Machined oil grooves allow for a supply of lubricating oil to enter the extension housing as well as the transmission case. The OE case bushing in vehicles with a GM TH400, 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. High-quality bronze Flange on the transmission case side prevents bushing from walking completely through the bore Flange accurately locates and helps retain the selective washer Machined oil grooves allow for a supply of lubricating oil to enter the extension housing as well as the transmission case.