Vacuum line?

[jays96]

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96 k1500 w 243c transfer case. I've been having rear output shaft seal leak on my transfer case and I heard vacuum line could be clogged and I noticed the elbow at the top of the transfer case in the center of the photo coming out of the transfer case with nothing connected to it. Is that where my vacuum line should be? I have already replaced my output shaft seal and is still leaking. Thanks

 

[xXxPARAGONxXx]

That's not a vacuum line. It's a vent line. A rubber vent hose should be connected to it.

 

[jays96]

That's not a vacuum line. It's a vent line. A rubber vent hose should be connected to it.

Thanks, how long should it be or where should it go. I was told my vacuum line could be clogged causing pressure which could cause the rear output seal leak. Not sure which line is the vacuum line.

 

[xXxPARAGONxXx]

Thanks, how long should it be or where should it go. I was told my vacuum line could be clogged causing pressure which could cause the rear output seal leak. Not sure which line is the vacuum line.

He was probably referring to that hose, but that hose is not a vacuum line or hose.

The engine produces a vacuum, but since that hose is not connected to the engine, there is definitely not a vacuum being pulled inside that hose.

A vacuum can also be created by a pressure or temperature differential (e.g., a railcar imploding after being steam cleaned and sealed off), but not going to happen within a transfer case.

We can't diagnose why your seal is leaking. It can be caused by many things. If you do think the vent line is plugged, all you have to do is stick a wire brush down into it or blow a brief shot of compressed air into it.

Edit: I think the vent hose mounts along the firewall attached to the fuel feed & return hose bracket.

If I am not mistaken, #3 in the first photo is a stud/bolt fastener that bolts into the transmission. Then #2 (hose bracket) in the second photo goes over that stud/bolt fastener and is secured by #4 (nut) in the first photo/ #3 (nut) in the second photo.

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[jays96]

He was probably referring to that hose, but that hose is not a vacuum line or hose.

The engine produces a vacuum, but since that hose is not connected to the engine, there is definitely not a vacuum being pulled inside that hose.

A vacuum can also be created by a pressure or temperature differential (e.g., a railcar imploding after being steam cleaned and sealed off), but not going to happen within a transfer case.

We can't diagnose why your seal is leaking. It can be caused by many things. If you do think the vent line is plugged, all you have to do is stick a wire brush down into it or blow a brief shot of compressed air into it.

I think the vent hose mounts to the back of the engine via small bracket on the hose. But, I don't have a photo of it.

He was probably referring to that hose, but that hose is not a vacuum line or hose.

The engine produces a vacuum, but since that hose is not connected to the engine, there is definitely not a vacuum being pulled inside that hose.

A vacuum can also be created by a pressure or temperature differential (e.g., a railcar imploding after being steam cleaned and sealed off), but not going to happen within a transfer case.

We can't diagnose why your seal is leaking. It can be caused by many things. If you do think the vent line is plugged, all you have to do is stick a wire brush down into it or blow a brief shot of compressed air into it.

I think the vent hose mounts to the back of the engine via small bracket on the hose. But, I don't have a photo of it.

 

[jays96]

Thank you. I believe this is the vent hose that should be on there and I will clean out the vent as you suggested. Go from there

 

[xXxPARAGONxXx]

gmpartsgiant is pretty good about providing exact part numbers.

Go here: https://www.gmpartsgiant.com/
Enter VIN.
Look under Transfer Case > Transfer Case Adapter & Vent Hoses.

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[jays96]

gmpartsgiant is pretty good about providing exact part numbers.

Go here: https://www.gmpartsgiant.com/
Enter VIN.
Look under Transfer Case > Transfer Case Adapter & Vent Hoses.

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Gotcha thanks

 

[89RCLB]

I have already replaced my output shaft seal and is still leaking.

A persistent leak after replacing the tail shaft seal is most likely a worn tail shaft bushing. (TH400 tail shaft for reference but directly applies).

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[Schurkey]

If that vent has not had a hose and valve connected to it for awhile, you'd do well to drop the transfer case fluid and replace with fresh. Remove the fill plug BEFORE you remove the drain plug.

The whole point of the hose and the vent-valve at the end, is to keep water/road splash out of the transfer case. Especially important if you're driving through deep water.

A persistent leak after replacing the tail shaft seal is most likely a worn tail shaft bushing. (TH400 tail shaft for reference but directly applies).

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Or a scored/worn driveshaft yoke--damaged at the seal area.