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  • Bushing walks out
  • Case damage
  • Metal contamination
  • Output shaft & case damage


Lack of flange or stop surface on the case bushing.


These no walk-out case bushings are flanged to prevent movement in either direction.

400, 4L80-E, 4L85-E

Case Bushing
Part No. 34006-OS


View Instructions

The OE case bushing in vehicles with a THM-400 or 4L80-E transmission tends to walk out of the housing bore. This allows the bushing to wander into the extension housing, leaves the output shaft unsupported, and may ruin the governor gear and cause case damage. Sonnax oversized case bushing 34006-OS for severly damaged cases is specially designed to remain in the case bore.

  • Oversized bushing has an oversized outer diameter where it presses into the case
  • Made from high-quality bearing bronze
  • Flange on the transmission case side prevents bushing from pushing 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 housing bore should measure between 2.1285"/2.1295" in diameter for an ideal fit. If the
bore meets this measurement, use Sonnax standard-size bushing 34006-SP. See instructions for details.

  • Material: Bronze
  • Bushing Style: Precision
  • Width: 0.690"
  • Shaft Dia.: 1.990"
  • Housing Bore: 2.171"
  • 34006 os