np231 aluminum shavings in case

So, has anybody run into something like this.

I pulled a 231 tcase from a 05 liberty due to noise/vibration at 50mph and the case running what I considered too hot (over 200 degrees with no load).

Cracked it open and found small chips of aluminum inside. Seems they are coming from the shift fork rod spring. It appears to be walking in a circle and the end of the spring is biting little chunks out of the housing (the chunks remind me of porting debris from porting aluminum heads). Should there be a washer on the end of the shaft between the case and the spring??? Anybody have a blow apart with good detail in that area?

Could it be that the case was run in 4wd over 45-50 and the chain slapping around eroded the case?

http://4x4trailhunters.com/media/pictures/article_20_3._NP231_TC_diagram.jpg

Nope, thats one of the first things I looked for. No evidence of the chain contacting the case. I think I've found the noise from a bearing, but belive it was caused by all the aluminum floating around in there.

THANKS for the diagram!!!

souske said:

Could it be that the case was run in 4wd over 45-50 and the chain slapping around eroded the case?

http://4x4trailhunters.com/media/pictures/article_20_3._NP231_TC_diagram.jpg

Click to expand...

the chain spins in 2wd also

ROBZ95Xj said:

the chain spins in 2wd also

Click to expand...

I believe he was referring to the chain stretching while over used in 4wd, not that it was only turning then.


I have given up on this one....the deeper I go, the worse it gets. Metal everywhere, every bearing is bad, and the case and tailcone have damage to the aluminum where the bearing sit.

Time for a new Tcase. Thanks guys.