GM 5.3 towing issues

[Beck]

I bought a new '16 Sierra last December. It just turned 10k miles yesterday. Today I bought a new 7 x 16 enclosed V-nose trailer. I had to tow it about 200 miles home. My Sierra has the 5.3 motor. The trailer was empty with only the spare tire inside. The truck could not pull that trailer at the 70 mph speed limit! It would accelerate the truck up to speed but refused to shift into the upper gears. This is a 6 speed. I'm not sure if it was in 4th or 5th, but the motor was turning 3000 rpm at 70 mph. If I would let off the gas I could coax it to shift up, but it soon downshifted again.

At 60 mph the truck got a 25 mile average of 11.5 mpg. When I speed up to 65 mph the economy dropped to 9.5 mpg , again a 25 mile average. At 65 mph the truck would downshift on moderate grades and then again upshift when it was crested.

I'm told these trucks are supposed to get good fuel economy. I average 17.5 mpg on the highway with the truck empty and just me in it. Not good in my opinion.

Does anyone have any idea what may be the issue. The truck will be visiting the dealer this week!

One friend of mine says it is common to all of the newer 5.3s. He is trying to talk me into trading on a Ford Ecoboost. I really don't want to trade the truck. Not that I hate Fords (bought a new Ranger that I put 160k on) but for the most part I have had GM stuff. My previous truck was a 2000 Silverado with a 5.3. I pulled a 8.5 x 20 enclosed trailer with a street rod in it with it.

[wayne petty]

digital page 229 describes the towing procedures..

http://www.gmc.com/content/dam/GMC/global/master/nscwebsite/en/home/Vehicles/Current_Vehicles/2016_Sierra_1500_Denali/Model_Overview/02_PDF/2016-gmc-sierra-denali-owners-manual.pdf

i wonder if the trucks computer knows there is a trailer attached when the trailer light connector is plugged in.

hopefully you will get an answer..

the   first section of the towing section states.. printed page 228..

Vehicles can tow in D (Drive).
Shift the transmission to a lower
gear if the transmission shifts
too often under heavy loads and/
or hilly conditions.
.
Turn off Park Assist when towing.

[Charlie Chops 1940]

I bought a new 2017 Grand Cherokee Trailhawk with a 5.7 hemi in August. Haven't towed a car trailer yet but it pulls my swap trailer like it isn't there at close to the advertised mpg of 22. September vacation saw 22 to mid 23's. It's an 8 speed automatic and has more bells and whistles than I'll ever be able to count...or use. It's rated to tow 7000 pounds but I doubt it'll get 15 while doing it although that would probably make me happy. Meanwhile it's a lap of luxury daily driver.

IMHO the manufacturers have lost their script in regards to work trucks by trying to make them into luxury cars. Pickups could probably be made to happily do the job intended for half the price and at a reasonable economy.

I'm getting too old for this crap....

[Ohio Blue Tip]

I have a 2014 Sierra 5.3 and pull a camp trailer of about 6000 lbs.
At 65 MPH I get 11 MPG.
Empty I get 20 MPG.
It's stock except no muffler, only cats.  Sounds good too.

[Crosley.In.AZ]

You have described my 2006 Silverado crew cab truck. It has given me consistent average of 17+ mpg on combo driving.  If it is on the freeway interstate only = near 20 mpg empty.

Hook up my empty aluminum car trailer = 12 - 13 mpg at freeway speeds : 70 mph.... In 4th gear on the 4L60E trans

loaded car trailer = 10 - 11 mpg at 65 - 70 mph.  All on flat ground.

Get the truck into the hills... loaded, up hills in 2nd gear at 3k RPM. I dont push it too hard

[Beck]

I visited my dealer this morning. I explained the problem. They ask what engine? 5.3. Then they ask what rear gears?  I didn't know. After looking up my VIN on their computer I found I had the 3.42 gears, which all 5.3s of that year did except those with the Max Tow option which got 3.73s.
GET THIS - I was then told by the service dept that, That truck won't tow that. It is rated at over 6k towing capacity. I estimate my weight is 3k. I was informed that it wasn't the weight it was the wind drag. I'm calling BS.

Ok, I'm aggravated now... I went inside to price a new truck with the 6.2. When looking at it's gear ratio I found it had 3.23 gear ratio... The Max Tow option with the 6.2 gets the 3.42 gears.  Now I'm afraid of that 6.2, so I step it up another notch and price the 3/4 ton Duramax. That is what I really wanted last year when I bought this one, but was to tight to pay that much. It turns out that for $24K and my truck, plus tax, title, doc fee, plate transfer I can get the truck I want.... I still own the 5.3..

I also looked at the Ford 3.5 EcoBoost. To get comparable equipment to what I currently have I needed to get a Lariat. The price to swap for one of those was $16k. One of my friends swears by them for towing.

It was suggested by a salesman that I try towing with the tow/haul mode off. I need to pull the trailer about 100 miles on Fri. with a load of about 750 lb. It is all 2 lane roads so I doubt I will get to test it at 70 mph.

[Beck]

IMHO the manufacturers have lost their script in regards to work trucks by trying to make them into luxury cars. Pickups could probably be made to happily do the job intended for half the price and at a reasonable economy.

Your right Charlie, but I do like those heated leather seats, and nav systems. Oh the reverse camera to park and hook up trailers is nice. I have got used to the crew cab.... Ooooo  Could I be the reason they made them into luxury cars??

My 2000 Silverado std cab long bed that I got rid of for this one did every job as good if not better than this one, and I wasn't afraid to use it any more since it was "broke in".

[Beck]

Another friend just took his Duramax in for oil and filter, air filter, and fuel filter at the Chevy dealer. He said the fuel filter part of the bill was $250.

[Beck]

I'm wondering if a cold air intake and a tuner would do my current truck much good? It would be a $800 experiment that may not solve the issue, but if it did it would be a lot cheaper than trading it in.

[UGLY OLDS]

I'm wondering if a cold air intake and a tuner would do my current truck much good? It would be a $800 experiment that may not solve the issue, but if it did it would be a lot cheaper than trading it in.

 A cold air intake & a change in tune will prolly do little more than void your warranty ....GM is VERY adamant on this .. They even have TSB's about tech's "finding" aftermarket tunes & where to look for them ...

Being a like new truck, I would pursue this up to the zone level & above.... Your truck should be able to tow that trailer .....Unless of course you are pulling into a 20+ MPH headwind......

 Let the dealer verify that "All is OK" with your truck & then get the zone involved ......Everyone is correct saying that it will not pull the trailer in the upper gears .....Not enough horsepressure ......


Bob ..  

[Charlie Chops 1940]

My last daily driver was the Trailblazer 4.2 I6,291 horses,similar torque.Trailer package with 3.73 gear and overdrive automatic.I toted the rpu tO Bonneville in a 14' boxtrailer and averaged about 12mpg for the trip. It would run 70 in overdrive on a billiard table or down hill or with a good tail wind, otherwise in third. It really had its tongue out on a few of those long steep passes in Colorado though. Crested a couple in 1st at 6000+ rpm and  about 25 mph. It had me worried but it never went backwards...LOL.

It survived and ran another 130k with no problems. It's best highway unloaded was 21-22 mpg right to trade in. I always keep in mind that we are asking a lot out of 300 horses in 5200 - 5500 trucks.

Charlie