Towing Question

[Sdp1234]

I'm driving a 6.0 2004 Denali. After testing the towing a couple time there is one thing I have a question about. 4000 pound trailer with brakes. When driving slowly 25-30 mph on level ground, coasting then accelerating a bit. Hard to explain but there is a point where going from coast to slight acceleration that the rpm's jump to catch up and there is a bit of a clunk. Any idea what I'm talking about? Thoughts on what it is and if it is a problem. Kind of like when you are driving a Motorcycle with a sloppy chain and you let off slightly and then accelerate. I could video it next time I tow.

 

[treehan77]

Are you pressing the tow button on the stalk? Or does Denali not have that?

 

[Sdp1234]

Yes I’m in tow mode which keeps the rpms up and keeps me out of overdrive I think My sure that is working This is not a huge problem and may not even be a problem at all Just wondering

 

[Fless]

Yes I’m in tow mode which keeps the rpms up and keeps me out of overdrive I think My sure that is working This is not a huge problem and may not even be a problem at all Just wondering

Tow mode doesn't lock out OD, it extends the shift points.

 

[Mechanic421]

Get used to the clunk they all do it. I have had two now. But I’m am going by my experience. Yours my be a different clunk . Mine is transfer case chain. There is a update but I just live with it. I can make mine clunk at will at parking lot speed.

 

[Sdp1234]

Get used to the clunk they all do it. I have had two now. But I’m am going by my experience. Yours my be a different clunk . Mine is transfer case chain. There is a update but I just live with it. I can make mine clunk at will at parking lot speed.

Maybe it’s not right but I’m glad to here you see it also. It really is at almost “parking lot” speeds. Those crazy 25 and 35 mph zones . With practice I can make it smoother

Thx

 

[Big Mama]

Same here. Some say the limited slip rear end is the clunk. I pull my boat around 5000 lbs but only use tow mode or manual shifting for climbing long hills. I’ve found that for flat driving and minor hills I don’t need the motor to work that hard. I also take off slowly. These things have great torque. I wish they were setup better to allow more weight.

 

[swathdiver]

I'm driving a 6.0 2004 Denali. After testing the towing a couple time there is one thing I have a question about. 4000 pound trailer with brakes. When driving slowly 25-30 mph on level ground, coasting then accelerating a bit. Hard to explain but there is a point where going from coast to slight acceleration that the rpm's jump to catch up and there is a bit of a clunk. Any idea what I'm talking about? Thoughts on what it is and if it is a problem. Kind of like when you are driving a Motorcycle with a sloppy chain and you let off slightly and then accelerate. I could video it next time I tow.

You're at minimums for using Tow/Haul with 4000 pounds, it's designed for use at 75%+ GCWR. So if you're GCWR is 14,000 pounds, you would not use it until the truck and trailer weigh 10,500 pounds.

 

[Sdp1234]

You're at minimums for using Tow/Haul with 4000 pounds, it's designed for use at 75%+ GCWR. So if you're GCWR is 14,000 pounds, you would not use it until the truck and trailer weigh 10,500 pounds.

I never heard this before. Does it cause problems.

 

[swathdiver]

I never heard this before. Does it cause problems.

No, it just does not provide much benefit, hard shifts, holds gears longer, etc. When mine is pulling a 5K trailer and in tow/haul, the transmission feels almost normal in operation. When empty and in tow/haul, the shifts are longer and more firm.

 

[SnowDrifter]

That's freewheeling in second gear. Some weird thing that t/h does. Not sure how it works or why it does it.

 

[bondservant2]

No, it just does not provide much benefit, hard shifts, holds gears longer, etc. When mine is pulling a 5K trailer and in tow/haul, the transmission feels almost normal in operation. When empty and in tow/haul, the shifts are longer and more firm.

I like to run in tow/haul mode on occasion even with nothing hooked up to the truck. I like being able to run a little higher engine rpm when it’s cold outside to get things warmed up (I’ve been running 10w-30 engine oil).
It takes a light foot on the throttle to keep things smooth, but that’s not an issue for what I perceive as a benefit.

 

[SnowDrifter]

I like to run in tow/haul mode on occasion even with nothing hooked up to the truck. I like being able to run a little higher engine rpm when it’s cold outside to get things warmed up (I’ve been running 10w-30 engine oil).
It takes a light foot on the throttle to keep things smooth, but that’s not an issue for what I perceive as a benefit.

We are different people

I keep my revs and load down until stuff warms up. Usually use my oil Pressure as a guide until it's at normal hot pressures