Now this I don't get,

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I was pulling my 5er toy haler (about 12k) up a fairly good grade on Tuesday afternoon coming back from the desert and a long weekend. I got to the top of the hill and stopped so my buddy could finish up the drive. As I was looking at the truck I noticed some fluid on the trans cross member. I looked under the truck and to my surprise there was fluid covering the front drive shaft and most of the left side of the trany and dif. I could see no discernable leak from any one area, checked the trans fluid and it still showed full.... O.K. so just to be safe I check the dif as well, it's fine to. Drove the truck home 90+ miles and didn’t experience anything strange with it other than the trany running about 75 to 100 degrees hotter than normal..... Checked it when I got home and no more fluid loss and the level still looked ok..... At dealer now anyone got a clue, cause I sure don't? Oh truck has 19K on it no issues to this point.<O:p></O:p>

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The Breather Vent.

Most likely your Allison transmission was "slightly" over filled by GM ,dealer or you if you have changed the fluid recently or paid someone to service.
In other words if you were in near the HOT side with a cold Allison fluid check,a good run and some heat will cause the fluid to expand resulting in a wet vent episode.

I wouldn't fret it one bit I have done the same without any harm what so ever.

Thx Mackin,



I just got a call to pick it up so I would think that it was not that serious!



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