High RPM Towing

[Johnny9r]

Not sure if this is the right section or not but I thought I would start here.

I have a 07 Yukon Denali with the 6.2 V8 and use it to tow my 30' travel trailer. The truck can tow 7900lbs according to the owners manual and has a pretty good cgvwr. Between my loaded trailer and truck I am 1000lbs under the CGVWR and all my axel weights are good, I had this checked on my local CAT scale.

Overall the truck pulls my trailer like a champ and it never feels like it is working hard to do it. The one thing I am troubled by is the fact that it stays in 4th gear at about 3k RPM when towing at 70 MPH. I am towing in a fairly flat area so it isn't shifting down ever from that but it will rarely get into 5th.

My question is should I be worried about the RPM's if the truck doesn't seem to be working hard? If so what could I do to help the truck get down into 5th some of the time. Any help is appreciated.

I would hate to have to get rid of the truck and get a 2500 something but I also don't want to have the vehicle break down on my somewhere because of what I'm doing.
Johnny9r

 

[rogersinsel]

Does the truck have a 6 speed?

 

[Johnny9r]

yes the truck has the 6 speed tranny in it

 

[05Yukon]

If you put it in manual and tap the shifter up to 5th or 6th will it go into 6th?

 

[TX LTZHoe 07]

I know this isnt the same, but my Tundra will hold 6th longer if it is in the manual mode. It is always in 6th on flats and sometimes drops to 5th on hills when pulling similar weights. Maybe 4th on really really steep grades.

I cant believe the 6.2/6 spd runs in 4th all the time with similar torque and power...

 

[Johnny9r]

it doesn't seem to want to shift up to 5th even in manual mode. I'm towing tomorrow so I will play around and see what happens.

If I can't get it up a gear would you guys worry about the engine / tranny at that RPM

 

[Rollin Thunder]

are you using tow/haul mode???

 

[Johnny9r]

i am using the tow mode, when i don't it sometimes gets into 5th but then hunts for gears. I know that is bad for the tranny so I don't do that often.

 

[WorldClass]

Your truck is working hard and the fact that it only stays in 4th gear is telling you that. The ECU calculates throttle position in relation to vehicle speed and many other sensors to determine the pulling load. If the load is too heavy for the most part it will not allow the shift to accure. I have a 1999 Tahoe with 3.42 gears with only the 5.7L engine and meany years ago I got talked into a 30ft TT and the trailer dealership said it would tow it no problem. I had a 12k stabilizer bar and tooled down the road. Needless to say it was not safe and came to find out that a 1/2 tone truck is no realy equiped to handle it. The wheel base is too short for the sway and the drive train was not powerfull enough. I then was able to get a 3/4 tone Suburban and it is trully night and day. There are people who will argue this point but you truck is saying your overweight. If you do alot of towing the trans will overheat, just a matter of time.
The rule of thumb for your size truck is 24 ft trailer and towing at the most 7400lbs.This is why, all automotive makers dont tell the consumers this but they come up with the tow rating with a bear bones truck, no A/C, learther seats, heated seats, third row seat, fog lights, and so on. Well now add all that weight of these onto the truck and there is an easy 500 lbs or so and that brings you down to 7400lbs to be on the safe side. Trailer manufactures are not on the up and up either, they do just the oppisit by coming up with the trailer weight with down near nothing in it. Example: GVW on trailer says 7000lbs, but add in one or two A/C units, heating, dish washer, ex. , you just took away 1000lbs or so. That true GVW is only 6000lbs. Trailer Life has alot of info on this as well, I'm just the guy who overhauls the burned up tansmissions. Hope this helps.