Noise When Towing

[SunnyInCo]

I did a search but did not see this question asked. I have a 2008 Yukon SLT with about 120,000 miles (I am the original owner). We just purchased a trailer and raft and did my first long tow this weekend. The trailer weighs about 800 lbs. with about 300 lbs. of cargo. It was a 2.5-hour drive going up some good elevation gains from 6,000 to a high of 11,000 ft on I-70 in Colorado. When we pulled over for the first stop, about 1.5 hours into the drive, I swore I can hear a whining, whizzing, whirling noise when the engine accelerates or decelerates at a low speed. I am assuming it is coming from the engine area.

Does this make sense to anyone? Any thoughts or ideas? Thank you!!!

 

[Big Mama]

Welcome to the forum from Virginia. A few questions. Did you hear this going up/down hill or both? On flat areas? Use tow/haul mode? Any noise when not towing? Did engine temp get high? Any DTC lights? Any brake issues?

 

[B-train]

Check your power steering fluid. Had a similar issue on my 2008 after it got hot climbing mountains in CO. I found that a little overfilled equals WAY overfilled when it gets to 200F. I had to siphon it out on the side of a mountain and let it cool with the engine running. Quiet as a mouse after.

Just a thought, but not necessarily the answer.

 

[B-train]

I forgot to mention that the overfilled expansion caused the pump to cavitate and create air pockets which then caused the pump to whine.

 

[SunnyInCo]

Welcome to the forum from Virginia. A few questions. Did you hear this going up/down hill or both? On flat areas? Use tow/haul mode? Any noise when not towing? Did engine temp get high? Any DTC lights? Any brake issues?

Thanks Big Mama. I heard it going from stop to accelerate and decelerate, basically when the engine and road noise was at their lowest. I did not notice the engine temp higher than normal, nor the warning lights came on. I used both the tow/haul mode and without the mode. I do not think it made a difference. The first stop was when I noticed it, I was using the tow mode. Appreciate your reply.

 

[SunnyInCo]

Check your power steering fluid. Had a similar issue on my 2008 after it got hot climbing mountains in CO. I found that a little overfilled equals WAY overfilled when it gets to 200F. I had to siphon it out on the side of a mountain and let it cool with the engine running. Quiet as a mouse after.

Just a thought, but not necessarily the answer.

Thank you!! I will look into this. I did have my power steering pump replaced last summer as the shop said "it was leaking". Who knows so maybe the fluid level is incorrect. Now that I think of it. The sound did kind of sound like you hear when you cut the wheel all the way and what I guess of the power steering fluid/pump in full activation mode. (i am not mechanically inclined at all so forgive my lack of knowledge.)

 

[SunnyInCo]

I forgot to mention that the overfilled expansion caused the pump to cavitate and create air pockets which then caused the pump to whine.

I guess my job tomorrow is to figure out how to check and verify the correct fluid level. ya, I am a rookie at this stuff.

 

[Foggy]

I guess my job tomorrow is to figure out how to check and verify the correct fluid level. ya, I am a rookie at this stuff.

Check your power steering fluid when cold.. There are lines on it that make it obvious.
Also, Since you are 1st owner, When was the last time you serviced your differentials? Transfer Case??
Transmission?? These could all also cause your noises...
BTW , that trailer is 'nothin' for your suv .. So I suspect it's more coincidence that
you found an issue while towing

 

[swathdiver]

I did a search but did not see this question asked. I have a 2008 Yukon SLT with about 120,000 miles (I am the original owner). We just purchased a trailer and raft and did my first long tow this weekend. The trailer weighs about 800 lbs. with about 300 lbs. of cargo. It was a 2.5-hour drive going up some good elevation gains from 6,000 to a high of 11,000 ft on I-70 in Colorado. When we pulled over for the first stop, about 1.5 hours into the drive, I swore I can hear a whining, whizzing, whirling noise when the engine accelerates or decelerates at a low speed. I am assuming it is coming from the engine area.

Does this make sense to anyone? Any thoughts or ideas? Thank you!!!

Power steering or maybe AC compressor whine. My AC compressor started making noise in 2018, still works fine. Just about every GMT900 at the gas pumps makes the same noise after a while, even my other pickup.

Tow/Haul is only really needed when you are at 75%+ of GCWR so it will have almost no effect on that light load your pulling. Did you go through the Eisenhower Tunnel?

 

[SunnyInCo]

Power steering or maybe AC compressor whine. My AC compressor started making noise in 2018, still works fine. Just about every GMT900 at the gas pumps makes the same noise after a while, even my other pickup.

Tow/Haul is only really needed when you are at 75%+ of GCWR so it will have almost no effect on that light load your pulling. Did you go through the Eisenhower Tunnel?

Yes, through the Eisenhower Tunnel. At the bottom of the pass we stopped in Silverthorn to meet up with everyone and this is where I first noticed the noise. I will look into the power steering and AC compressor. Thanks.