front seal on rear hog head

Capt. Morgan · Post by **Capt. Morgan** » Sat Dec 01, 2007 12:56 pm

this topic is to help other cc owners keep an eye open for this issue me and 2 other of my friends who also own cc 1 reg. LS and another a zr5. the front seal failed and water sipped in to the rear hog head and pushed out the oil which in turn costed me almost 1000 bucks right before christmas last year.

Post by **HenryJ** » Sat Dec 01, 2007 1:00 pm

It must be an IL thing? Is "Hog Head" , the differential housing? The seal you refer to being the pinion seal?

Capt. Morgan · Post by **Capt. Morgan** » Sat Dec 01, 2007 1:12 pm

yes that is correct.I have also heard it called a pumpkin

F9K9 · Post by **F9K9** » Sat Dec 01, 2007 1:30 pm

There is a TSB concerning the issue. You need to reroute your rear diff. vent hose from between the bed and cab to somewhere else. Water is getting into the rear diff via that hose. I'll try and relocate it for you.

F9K9 · Post by **F9K9** » Sat Dec 01, 2007 1:37 pm

GM DATA wrote: Document ID# 1548738
2002 Chevrolet S10 Pickup - 4WD
Diagnostic Information on Rear Axle Vent Hose to Avoid Moisture/Water Intrusion #04-04-20-003 - (Sep 3, 2004)
Diagnostic Information on Rear Axle Vent Hose to Avoid Moisture/Water Intrusion

2001-2004 Chevrolet S-10 Four-Door Crew Cab Pickup

2001-2004 GMC Sonoma Four-Door Crew Cab Pickup

When diagnosing a rear axle leak or noise concern on the above-listed vehicles, a technician may find that the rear axle fluid is contaminated with water.

First inspect the rear axle vent hose routing location. The vent hose may be positioned directly below the gap between the cab and the pickup bed. In this location, the vent hose may be more susceptible to water/moisture intrusion from the elements or from automatic car washes. It may be necessary to relocate the vent hose to a new location under the pickup bed that will prevent moisture/water from entering the hose.

Post by **HenryJ** » Sat Dec 01, 2007 2:51 pm

I would say Reeds advice is sound. Removing the rear cover and inspecting the condition of the bearings is a good idea. The contamination may have been just the beginning. Usually a loose pinion leaks. Sure the seal can go first, but I would at least check the condition of the internal parts to rule out a bearing failure as the cause of the pinion seal leak.

Post by **HenryJ** » Sat Sep 27, 2008 4:10 pm

HenryJ wrote:Usually a loose pinion leaks.

"Usually" had to be the key word. Not always is for sure.
Doing a good service on my truck, I found my pinion loose. The driveshaft moved quite a bit. i thought maybe U-joints, but no they are smooth and tight. No leaks and the diff is full.
It took probably a good half turn to take the slack out of the pinion bearings. glad I caught it here rather than in the middle of Moab somewhere.

If you happen to be crawling around underneath, give the driveshaft a good push and pull.