Please Help Guess the Part!!!

[YukonandtheHOE]

I’ll throw my 2cents in. That is definitely an in-line filter, that hard line in the last pic is what that hoes connects to that goes under the engine compartment to keep the vents up high, over time the pressures created by heat in the diff propably siphoned the oil out of that hose because it’s so low or a leaky wheel seal. Generally speaking gears don’t make noise when coasting so you may have a bent rim or a tire issue causing the vibration.

 

[warriormagee]

I’ll throw my 2cents in. That is definitely an in-line filter, that hard line in the last pic is what that hoes connects to that goes under the engine compartment to keep the vents up high, over time the pressures created by heat in the diff propably siphoned the oil out of that hose because it’s so low or a leaky wheel seal. Generally speaking gears don’t make noise when coasting so you may have a bent rim or a tire issue causing the vibration.

Thank you. The noise goes away (or doesn't start) while the gas pedal is depressed, only when I take my foot off the gas pedal after I have achieved cruising speed. The noise isn't there the whole time I'm coasting either, it comes and goes on it's own. If I drive the same stretch of road at the same speed, it might happen once or twice, or it might happen the whole stretch of the road. Sometimes it is really loud with a lot of vibration in the floor, sometimes the sound is very low with no vibrations felt. There is no rhyme or reason that I can nail down, other than the vehicle coasting.

 

[YukonandtheHOE]

It could be the engine going from v8 to v4 causing misfire and shaking the exhaust. My 07 was doing that until I swapped out the spark plugs

 

[warriormagee]

It could be the engine going from v8 to v4 causing misfire and shaking the exhaust. My 07 was doing that until I swapped out the spark plugs

Ok, I'll check that. Was there any wear or marks on the plugs that looked abnormal?

 

[YukonandtheHOE]

They were original equipment(wore out)
GM suggests change them every 150k miles. I replaced them with AC Delcos, the conductors were pretty much all burnt out. Had a >1/8 gap lol

 

[shoplizard]

Hi I have a couple of suggestions for you. First, when you check the u joint for slack, set the parking brake and put chokes under the wheels, then put the trans in neutral, engine off. Grab the rear of the prop shaft and check for movement. If the u-joint is bad it will most likely rattle and you will see the slack. Also, grab the flange on the differential and attempt to move it up and down, should have no movement up and down. There is a possibility that the u-joint is rusted up and seized, this is difficult to determine without removing the 4 bolts to the straps and removing the rear of the prop shaft and checking fo a smooth rocking motion of both crosses of the u-joint. If it binds the u-joint should be replaced. With the shaft off, check the diff flange again for movement up and down.
Second, recheck the diff fluid for color and metallic appearance after driving and warming it up. Fluid should be a clear appearance (may be dark) with no metallic look (grey). If it is grey, and the diff flange moves up and down, most likely the diff is toast.

 

[warriormagee]

Hi I have a couple of suggestions for you. First, when you check the u joint for slack, set the parking brake and put chokes under the wheels, then put the trans in neutral, engine off. Grab the rear of the prop shaft and check for movement. If the u-joint is bad it will most likely rattle and you will see the slack. Also, grab the flange on the differential and attempt to move it up and down, should have no movement up and down. There is a possibility that the u-joint is rusted up and seized, this is difficult to determine without removing the 4 bolts to the straps and removing the rear of the prop shaft and checking fo a smooth rocking motion of both crosses of the u-joint. If it binds the u-joint should be replaced. With the shaft off, check the diff flange again for movement up and down.
Second, recheck the diff fluid for color and metallic appearance after driving and warming it up. Fluid should be a clear appearance (may be dark) with no metallic look (grey). If it is grey, and the diff flange moves up and down, most likely the diff is toast.

Thank you for the suggestions.

 

[warriormagee]

Hi I have a couple of suggestions for you. First, when you check the u joint for slack, set the parking brake and put chokes under the wheels, then put the trans in neutral, engine off. Grab the rear of the prop shaft and check for movement. If the u-joint is bad it will most likely rattle and you will see the slack. Also, grab the flange on the differential and attempt to move it up and down, should have no movement up and down. There is a possibility that the u-joint is rusted up and seized, this is difficult to determine without removing the 4 bolts to the straps and removing the rear of the prop shaft and checking fo a smooth rocking motion of both crosses of the u-joint. If it binds the u-joint should be replaced. With the shaft off, check the diff flange again for movement up and down.
Second, recheck the diff fluid for color and metallic appearance after driving and warming it up. Fluid should be a clear appearance (may be dark) with no metallic look (grey). If it is grey, and the diff flange moves up and down, most likely the diff is toast.

(FYI Rear differential on 2WD Yukon XL)
New Info!!! I tried to check the U-Joint. There was movement, but no rattling. I took video, but can't get it to upload yet. While doing this, new drop of fluid rolled down from behind the collar that attaches to the U-Joint. That whole area is covered in fluid, so much so that just grabbing it coated my hand. I didn't take the U-Joint loose yet, waiting on feedback from this discovery.

 

[shoplizard]

The amount of oil coming from behind the yoke is very minimal. A seriously leaking seal will fling oil all over everything. I don't believe the seal is a problem. You are still going to have to perform the checks I suggested to be able to come to some conclusion as to what your problem is, Good luck ( I know it is a lot of work to be done on the ground, don't break any knuckles).

 

[warriormagee]

The amount of oil coming from behind the yoke is very minimal. A seriously leaking seal will fling oil all over everything. I don't believe the seal is a problem. You are still going to have to perform the checks I suggested to be able to come to some conclusion as to what your problem is, Good luck ( I know it is a lot of work to be done on the ground, don't break any knuckles).

There is a lot of movement coming from the yoke (collar where the oil is coming from). I can't get the video from my phone to upload.