Identify Hose Hanging Off Auto Transmission

Gringo Loco · May 27, 2009

Hi,

Can someone identify what and where this hose hanging off my transmission goes to? I noticed something hanging below the truck, and went underneath to take a look. I can't find any glaring places it goes to. See attached pic.

My truck is a 99 GMC Sierra 1500 SLT Ext Cab 2WD 5.3L (New Body Style - SWB). I'm fairly certain it is a 4L60E Auto Transmission. It is a deep pan with an auxiliary cooler. Truck has about 125K on it and runs great.

Also a few other questions:

Seems to be a lot of gunk around the u-joint drive shaft ... could there be a leak? I've changed out the ATF and filter before and don't recall this. That was at about 35K and I've since had an ind. service shop do a flush. They used a machine. Hope one of those quick lube techs didn't mess something up.

Other question: This is a deep pan and I am considering doing another AT fluid and filter change myself. I've seen references to filters for 2 1/8 and2 7/8 deep pans for filter kits? I'm not sure which to order. Can a guy just take the external measurement to determine this? Last time, the parts store just got it right. I was not aware of more than one size of deep pan.

Thanks for any assistance you may provide.

Stevens03 · May 27, 2009

EXTRA long breather tube. Just cut it shorter, but before cutting make sure it's still goes into the transmission.

Gringo Loco · May 28, 2009

Well, just to follow up on this if someone else ever has the same issue, I found where I believe the hose is supposed to go. I've attached another pic and circled two plastic clips in red. The clip on the left attached to the three steel fuel lines is where I clipped the open end. The clip on the right is just to illustrate the clip a little better since the one on the left is difficult to discern in the pic. They are both identical. The one on the left had come open. I'm pretty sure a drive through a field in East Texas with 5' to 6' tall weeds probably snagged it and pulled it loose. I haven't traced the other end but don't believe it has pulled loose from the transmission. It seems to be pretty snug on the other end and the fluid looks good on the dipstick.

txab · May 28, 2009

Is the cat optional equipment?

Gringo Loco · May 28, 2009

... make sure it's still goes into the transmission.

Are you talking about the other end of the hose? ... or the end that hangs? This hose never hung this low before. Not sure when it happened. I'm not sure where the other end leads to. It goes on top of the transmission and that space is very tight. I'm not sure I could trace that.

The cat is optional. Friendly guy likes to come over from the neighbors and visit with our cats through the window. He loses no opportunity to investigate if I'm in the garage or tinkering. I call him Mr. Cat, because I don't know his name.

Draenor · May 28, 2009

Most likely the vent tube. I cant recall if a filter is supposed to be installed on the end.

Stevens03 · May 28, 2009

Follow the hose back to the transmission and make sure its pushed into the trans. Then the other part thats hanging low can be cut.

Gringo Loco · May 28, 2009

Follow the hose back to the transmission and make sure its pushed into the trans. Then the other part thats hanging low can be cut.

That's what I thought but wanted to be sure. I believe it is the vent hose. I looked it up in the service manual (see attached pic) ... only a very brief mention of it in there and a partial illustration which cuts off before it shows where it actually enters the trans ... wouldn't you know it?

I'll try to trace it but since it's on top, that is very tight and not sure if I'll be able to. Anyways, thanks for the assist guys.