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.

 

[SunnyInCo]

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

I changed all the differential, transmission, and transfer cases fluids about 10 months ago, which equated to not a lot of miles. I bet not more than 8,000. This is typically the mountain/travel vehicle. I was curious as to going uphill for 50 or so miles if that put some undo stress on something.

Going uphill I like to keep my momentum and was averaging in the 65-70 mph range. On the steeper sections, I did have to punch it in the 4,000 rpm range, especially ascending i-70 to the tunnels from the Silverthorn side if that matters to anyone.

 

[swathdiver]

I did have to punch it in the 4,000 rpm range, especially ascending i-70 to the tunnels from the Silverthorn side if that matters to anyone.

She can run like that all day long.

 

[SunnyInCo]

She can run like that all day long.

Thanks for this. I typically do not push the engine to this level, at least not for longer than a few seconds to get her into the next gear on a steep climb. It did make me very nervous.

 

[Geotrash]

Thanks for this. I typically do not push the engine to this level, at least not for longer than a few seconds to get her into the next gear on a steep climb. It did make me very nervous.

Yeah, it did for me at first too. Then I remembered that there are 3500's with the 6.0 and 6L90 pulling 15,000 lb 5th wheel campers, and those things are screamin' all the time. It's the nature of the beast and these engines are built to handle it. I pull a 7500 lb camper with our 2012 XL Denali and it does great. Pulled it out west through the Tetons and Yellowstone and it stayed nice and cool.

Heck, this guy used to pull 12,000 lbs with his Escalade. Not recommended, of course.

Info: - My Upfit Build Story

www.dieselplace.com

 

[steiny93]

I think that vintage has electric fan's for cooling.
Any chance the noise was the fan's being engaged?

 

[SunnyInCo]

I think that vintage has electric fan's for cooling.
Any chance the noise was the fan's being engaged?

Sorry, have not be on the forum for a while.

After a few trips, I believe the issue is when downshifting to 2nd and 3rd gear for 10 miles. We always stop at the same place for a nature break and after the car sits for a few minutes, the noise goes away.

 

[SunnyInCo]

She can run like that all day long.

After a few trips up to the mountains, i need to punch it in the 5,000 rpm range sometimes to keep momentum. I try not to keep it at this level for more than 10 to 20 seconds at a time as the engine is roaring at this point.

I wish this had a few more gears. The transmission shifting from 3rd to 4th and back down is at that level where sometimes it is bouncing between the two and I really need to manage the speed.

 

[swathdiver]

After a few trips up to the mountains, i need to punch it in the 5,000 rpm range sometimes to keep momentum. I try not to keep it at this level for more than 10 to 20 seconds at a time as the engine is roaring at this point.

I wish this had a few more gears. The transmission shifting from 3rd to 4th and back down is at that level where sometimes it is bouncing between the two and I really need to manage the speed.

Just lock her into 3rd and let it rev. It's best for cooling anyway.

 

[donjetman]

I wish this had a few more gears.

We had a 4L60 in our 02 Surburban and it needed more gears too.

 

[SunnyInCo]

Just lock her into 3rd and let it rev. It's best for cooling anyway.

I assume you mean manually shift in the D3 gear and head up the hills in that mode? Thank you!!!