Auto Transfer Case?

2004rado · June 30, 2008

Question on transfer case fluid level? I change the Oil in my 2004 K1500 Silverado w/ auto transfer case. When I pulled the fill plug, I got about 1.5 to 2.0 quarts of reddish blue fluid out. Then I pulled the drain plug to drain the rest of the fluid. All fluid removed totals about 3.5 to 4.0 quarts. Manual states fluid level just below fill plug. When I replaced with 1.8 liters of Auto-Trak II fulid. My question is was the transfer case over filled at the factory, or could the auto transmission be leaking into the transfer case?

MS3DALE · June 30, 2008

Sounds like the trannsmission fluid is leaking into the transfer case,The transfer case fluid should have been Blue...Not Reddish-Blue,And it should have only had 2 quarts of fluid in it,Not 4.

None,to very very little fluid should have come out when you pulled the fill plug.

MS3DALE · June 30, 2008

BTW.....Check your transmission fluid,I bet its a couple quarts low!!

2004rado · June 30, 2008

Thanks MS3DALE, Trans fluid is low. I guess I will be going by the dealer tomorrow. Do you think the transfer case will need to be flushed out? Anything else I should know before I see the GM Dealer?

MS3DALE · June 30, 2008

Yes,If the transmission fluid is leaking into the transfer case I would flush out the fluid once you get the leak repaired and put fresh AutoTrakII fluid in.

akram · April 1, 2009

Sounds like the trannsmission fluid is leaking into the transfer case,The transfer case fluid should have been Blue...Not Reddish-Blue,And it should have only had 2 quarts of fluid in it,Not 4.
None,to very very little fluid should have come out when you pulled the fill plug.

I'm changing the transfer case fluid on my 06 Sierra 1500 and saw your comment that very little fluid should come out the drain plug, this seems odd since it takes two quarts to fill. Where is the rest of the fluid? When I pulled the plug on mine the same thing happened, very little fluid came out, I'm reluctant to pour two quarts of fluid in there without getting more out. Is there a second drain plug somewhere?

alaska511 · April 1, 2009

Sounds like the trannsmission fluid is leaking into the transfer case,The transfer case fluid should have been Blue...Not Reddish-Blue,And it should have only had 2 quarts of fluid in it,Not 4.
None,to very very little fluid should have come out when you pulled the fill plug.

I'm changing the transfer case fluid on my 06 Sierra 1500 and saw your comment that very little fluid should come out the drain plug, this seems odd since it takes two quarts to fill. Where is the rest of the fluid? When I pulled the plug on mine the same thing happened, very little fluid came out, I'm reluctant to pour two quarts of fluid in there without getting more out. Is there a second drain plug somewhere?

He said fill plug, not drain plug.

If you got very little, then there is an issue. The drain is at the bottom.

I can confirm, they do hold 2 quarts, and that is what you should have drained.

akram · April 3, 2009

Any idea on what issue I might be looking at, there were no visable leaks to the Tcase, could it be leaking in the transmission? Or maybe it was never filled right to begin with. I bought the truck used last fall so who knows what the previous owner did.

alaska511 · April 3, 2009

Any idea on what issue I might be looking at, there were no visable leaks to the Tcase, could it be leaking in the transmission? Or maybe it was never filled right to begin with. I bought the truck used last fall so who knows what the previous owner did.

Not possible. It would not leak into the transmission. If there was a leak at that seal, you would have trans fluid in the t-case, and the t-case would be over full.

The previous owner must have not filled it properly.

akram · April 3, 2009

That's what I'm thinking, are you in Anchorage? I'm in Fairbanks.

alaska511 · April 3, 2009

That's what I'm thinking, are you in Anchorage? I'm in Fairbanks.

I am right now. We are in the middle of relocating to Oregon. House sale should be closing on the 16th.

BrockwayMT · April 28, 2009

Any idea on what issue I might be looking at, there were no visable leaks to the Tcase, could it be leaking in the transmission? Or maybe it was never filled right to begin with. I bought the truck used last fall so who knows what the previous owner did.

Not possible. It would not leak into the transmission. If there was a leak at that seal, you would have trans fluid in the t-case, and the t-case would be over full.

The previous owner must have not filled it properly.

It is possible. If the pilot bearing in the input gear of the transfercase walks aft the mainshaft in the transfercase can wear hole in the bearing cup. The transfercase then pumps oil into the transmission.

alaska511 · April 28, 2009

Any idea on what issue I might be looking at, there were no visable leaks to the Tcase, could it be leaking in the transmission? Or maybe it was never filled right to begin with. I bought the truck used last fall so who knows what the previous owner did.

Not possible. It would not leak into the transmission. If there was a leak at that seal, you would have trans fluid in the t-case, and the t-case would be over full.

The previous owner must have not filled it properly.

It is possible. If the pilot bearing in the input gear of the transfercase walks aft the mainshaft in the transfercase can wear hole in the bearing cup. The transfercase then pumps oil into the transmission.

On a 246 mated to a 4l60? I have heard of this on older models (non auto NVGs), but I didn't think the input bearing on a 246 had the lube pressure from the pump.

BrockwayMT · April 28, 2009

Any idea on what issue I might be looking at, there were no visable leaks to the Tcase, could it be leaking in the transmission? Or maybe it was never filled right to begin with. I bought the truck used last fall so who knows what the previous owner did.

Not possible. It would not leak into the transmission. If there was a leak at that seal, you would have trans fluid in the t-case, and the t-case would be over full.

The previous owner must have not filled it properly.

It is possible. If the pilot bearing in the input gear of the transfercase walks aft the mainshaft in the transfercase can wear hole in the bearing cup. The transfercase then pumps oil into the transmission.

On a 246 mated to a 4l60? I have heard of this on older models (non auto NVGs), but I didn't think the input bearing on a 246 had the lube pressure from the pump.

Input bearing doesn't have direct lube from the pump, but the pilot bearing does. Oiling system is pretty much the same as on a part time except there is a restrictor in the end of the mainshaft to put more oil through the clutch. If the pilot bearing leaks the oil doesn't have to get past the input seal as the oil bypasses the seal inside of the input gear.