So today I was just checking my oil and wiping down the engine a little and noticed this hose. I don't feel like crawling under the truck right now because I have to leave in a few but I was wondering if someone could tell me what this hose goes to. It doesn't feel like it's attached to anything where it turns and goes back under the engine.

 

It's a vent line for the tranny. It's supposed to be there.

 

Partially correct. It is a vent, but it is the front differential vent.

 

My bad. But it IS supposed to be there.

 

ok so the next time i get under the truck i will chase it and check it out. if it happens to not be hooked up where does it hook into the front diff so i can make sure its doing its job?

 

It attaches to the differential. It is a vent hose, and that funny looking thing on top is a one way check valve.

There should also be a vent hose from your t-case and your rear axle. The rear axle ends at the bottom of the body.
The t-case by the distributor.
The tranny also has a vent tube, its located on the backside of the bellhousing on top of the tranny. Older versions its 4" long, newer versions its about 12" long nad hangs on the side of the tranny.

IF your doing any water crossings you need to be away of those hoses and its preferred to run them as high as possible in the engine compartment or better yet in the cab of the truck.

 

When I originally found this hose on my 97 Blazer LS it was lying loose under the oil filter in or near the oil filter access door. At first I could not for the life of me figure out where it went or what it went to. I noticed a vacant hose fastener/clamp near the top of my radiator, so I surmised that this where the hose originally went for one it was the right size to hold the hose and the hose seemed to reach that location beautifully. So I placed it there about two years ago. However I did not know that is is supposed to have a check valve in the end of it until I saw this post today. What is the exact name of this part? What kinds of problems might I have if I don't replace the missing check valve? As stated earlier I have been running without this check valve for going on two years now. Have done some considerable towing with this truck in the past and I currently tow a concessions cart with my truck 4 to 6 days a week. Any advice you have will be greatly appreciated. Also, I just wanted to say thank you for your post on fixing cold solders on wiper motors. I was experiencing wiper problems, that were exactly as you described as having a mind of its own. Last weekend I printed up your post and am very happy to report that my wipers now work beautifully. Thank again it was a quick fix and saved me some of my hard earned money.