GM Service Manual Online
For 1990-2009 cars only

Fluid Leak From The Extension Housing Seal On 4L80E/ 4L85E Transmission - keywords engineering investigate prop shaft yoke

Subject:Fluid Leak From The Extension Housing Seal On 4L80E/4L85E Transmission

Models:2008-2009 Chevrolet Express Van 2500/3500
2008-2009 GMC Savana Van 2500/3500
Equipped With a 4L80E/4L85E Transmission RPO MT1 or MN8 and Two Wheel Drive



This PI was superseded to extend investigation and update models. Please discard PIP4207A.


The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

Condition/Concern:

Customer may comment on transmission fluid coming out of the transmission extension housing seal on either the 4L80E or 4L85E transmissions.

Recommendation/Instructions:

Until November 30, 2008, GM Powertrain Division is requesting that additional parts be replaced and returned for analysis of extension housing seal leaks. If a fluid leak is diagnosed as coming from the transmission extension housing seal (use fluid dye if necessary), please replace the extension housing and seal together, without removing the seal from the housing. Also replace the slip yoke to facilitate analysis of the yoke and seal inner diameter.

Use Labor Operation K6390: Housing and/or Housing to Case O-Ring Seal or Gasket, Extension - Replace.

After November 30, 2008, please disregard this request and repair the fluid leak condition in the normal manner.

Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.