Please Help Guess the Part!!!

[warriormagee]

2007 GMC Yukon XL 2WD 5.3L

I was trying to run down a vibration/rubbing sound I thought was coming from the rear differential. The outside of the transfer case is dry. Hanging down beside the transfer case was what looks like some sort of inline filter, connected on one side to a rubber hose. I assume the other side is supposed to be connected to another rubber hose. Looking for the other hose, I noticed what looked like a squarish box bolted to the bed, just in front of and above the rear transfer case. This whole area is covered in some type of fluid that I assume is because the filter looking piece isn't correctly attached any more. Couldn't detect an identifying smell.

** What is the inline filter looking thing?

** What kind of fluid might it be?

** What is the squarish box bolted to the underside of the bed.

 

[Doubeleive]

pics? were playing guess a whack a mole, fluid color? square box could be air ride pump but is generally close to the drivers side rear axle

 

[warriormagee]

pics? were playing guess a whack a mole, fluid color? square box could be air ride pump but is generally close to the drivers side rear axle

It was too dark for pics tonight. The fluid looked dark/black. It wasn't dripping wet (not sure how long it had been there/the filter looking thing had been unhooked). I was hoping that there couldn't be many inline filters in that area, so it would be easy to name. Not a fuel filter though, as there is no gas smell and I'm not losing fuel.

 

[Doubeleive]

I don't think there is any unless someone added one to something, if so I would be maintenancing mine, fuel filter is in the gas tank they eliminated the one that used to be under the driver against the frame.

 

[Rocket Man]

If you're talking about a big squarish box in front of the rear differential and not the " rear transfer case" it might be the vapor canister which is part of the emissions. There are hoses going to it, as well as at least one valve. If something is disconnected to that system you should be getting a message on the DIC though. The only fluid in that area should be either differential fluid or fuel. I would suspect you'd know if it was fuel though from the smell.

 

[warriormagee]

Best pics I could get tonight. It felt like the hose connected to the filter went to the top of the rear transfer case. I'm thinking that the hose not connected to anything is the one that is supposed to be connected, unless it is some sort of loose vacuum tube. I'm still super confused. Transfer case fluid should be the only thing going in the transfer case...so does fluid travel between the front and rear transfer cases?

 

[warriormagee]

If you're talking about a big squarish box in front of the rear differential and not the " rear transfer case" it might be the vapor canister which is part of the emissions. There are hoses going to it, as well as at least one valve. If something is disconnected to that system you should be getting a message on the DIC though. The only fluid in that area should be either differential fluid or fuel. I would suspect you'd know if it was fuel though from the smell.

Definitely not fuel, so I guess it is differential fluid (which is supported by my newest findings. I always thought that the differentials were a closed environment. I didn't know fluid traveled into and out of them. Is there only one spot to add new differential fluid?

 

[PG01]

Thats a vent for the transfer case, the original fell off and someone put a fuel filter on. A differential is the rear pumpkin looking housing with axle tubes sticking out of it that have your wheels on either end.

 

[PG01]

And it prob had fluid blowing out of it so they put that on to stop it. Check transfer case fluid level

 

[PG01]

Transfer case is right behind transmission. differentials, on a 4wd, are in the front and rear, pumpkin looking things

 

[warriormagee]

Thanks all. My terminology was a little screwed up, I was using transfer case and differentials interchangeably. I'll check the rear differential fluid. The bolts to drain and fill the rear differential are on the rear differential, correct? Any suggestions on the fluid/additives to put back in a 2WD with 140K miles?

 

[PG01]

Yeah, i jyst realizedyou were 2wd, still tho differential in back, between wheels and thats a vent and whats supposed to be in there is pic i posted and it should be secured above diff. Cover on that diff has a square holed plug in it that you fill it through. Usually a 3/8 ratchet fits in, with an extension. Fluid should be up to bottom of that fill plug. Check owners manual for correct fluid type and amt. if its wet on the floorboards in front and above the rear diff the pinion seal is bad.

 

[warriormagee]

Regarding the vent, is the open end supposed to be connected to the loose rubber tube in the pic? Or is it supposed to be open on that one end, and just mounted so that the open end is above the rear differential?

 

[PG01]

Regarding the vent, is the open end supposed to be connected to the loose rubber tube in the pic? Or is it supposed to be open on that one end, and just mounted so that the open end is above the rear differential?

Supposed to be a vent in like the pic i posted and mounted to floor board above diff somewhere loosely so there is slack

 

[warriormagee]

Thanks. Any idea what the hose in this pic is for, and if it should be attached to anything?

 

[PG01]

You need to take better pics, sorry i cant tell if its e brake cable wrapped around exhaust hanger or what...

 

[warriormagee]

I'm fairly certain the inline filter connected to that hose. I was able to get in there and run it to down, and the end of that hose that isn't seen has a black piece in it that looks like the vent tube pieces you showed me. I connected it back together.

Then I opened the fill bolt on the differential. It was still wet inside, but I couldn't feel any fluid. I added over 3/4 of a bottle of 75W90 (as specified in my manual). I took it for a test drive and there is a rough vibration/rubbing sound when coming from the back of the vehicle when it coasts (i.e I get the vehicle up to road speed and then take my foot off the gas). The vibration/sound sometimes happens as soon as I start coasting, and sometimes it will coast several feet before it starts. There is no vibration/sound when giving the vehicle gas. The vibration/sound happens in any gear and in Neutral if I shift to Neutral after getting up to speed.

Is my differential toast, or is there hope yet?

 

[PG01]

Could be rear u joint but since you’re saying there wasnt any fluid in the diff it may be the case

 

[HiHoeSilver]

Pull the cover off and look at it....

 

[PG01]

Thing is fluid didnt just evaporate into thin air... did you look at tge pinion seal, does it look wet? How about your rims? Seam oily, extra brake dust caked on?