Jump to content

Recommended Posts

Hey guys,

 

A little back story real quick. I had a 2006 Chevy HD2500 2x4 Duramax with the LLY engine. After about 175,000 miles I had issues pulling heavy trailers " trailers over 5k in weight". A check engine light would come on and if I did not do something quickly it would go into limp mode. The CP3 pump can't keep up or I have an injector issue. Not cheap fixes and I lived with this issue for some time. I borrowed friends trucks for a while and finally once I hit 230,000 miles I decided this was the day I upgrade.

 

I went all in and bought an off the lot 2016 GMC 4x4 Duramax Denali with 108 miles on the clock. For the most part this truck has been fantastic. I had an issue with vibration. The dealership balanced and rotated the tires. That fixed that problem.

 

A few weeks ago I loaded my 24ft enclosed trailer with 2 UTV's and pack and headed from Dallas to the sand dunes in Oklahoma. I was with a buddy driving a 46 foot motor home with a 450hp Cumin's pulling a 20ft enclosed trailer with 2 UTV's and pack. The motor home would pull away and I was not able to keep up.

 

Here is my issue or concern with this truck. I was not able to keep up on speed pulling 8000lbs. I held the pedal to the floor and was able to run a top speed of 70-72 mph. Needless to say I have been very disappointed since that trip. All I hear now from my friends with trucks is that I should have bought a Ford. I did not want a Ford I wanted a GMC and that is what I bought.

 

Here is what I know to be true. I had 2000 miles on the truck before this trip. I did have the truck in tow mode when pulling trailers. The transmission would shift from 6th to 5th in drive under load. Would not shift to 4th on its own in drive. If I put it in manual mode and down shifted to 4th it had all kinds of power and picked up speed. Another test I ran was using cruse control. If I bump cruse from where I was 72mph to 80mph it would jump down to 4th and take off and run 80. I am not a fan of cruse in traffic going up and down hills through Oklahoma. And I used 3.5 gallons of def in 3000 miles. That seems excessive but then again I had to hold it to the floor to maintain speed.

 

I made an appointment with my dealer and they could not find anything wrong. They asked if I could get my trailer and have a technician ride with me and duplicate this issue. That is scheduled for 11/16/16. I will be happy to update this forum with the results of that test run.

 

I am asking the folks on this thread. Does that seem right? I am looking for suggestions please. I have to hold the pedal to the floor to pull 8000lbs and only get 70-72mph? It was windy that day and I did have some head wind. I could speed up going down hill and hold speed for the most part going up the next hill. If I was on flat ground or pulling any kind of grade I was stuck at 72 max.

 

BTW running the truck empty it runs good. I do feel like my 2006 is more responsive and quicker. That was not a requirement when I bought the truck. Being able to pull heavy trailers at highway speed is a requirement.

 

Thank You for reading my post if you made it this far.

Link to comment
Share on other sites

3.5gal of DEF in 3k miles sounds about normal, I'd say slightly better seeing as you had to work it a bit there on your trip. DEF on 3/4-1 ton diesels is about 4000-6000 miles out of 5 gallons of DEF. Has a lot to do with regen cycles as to the consumption rate. I'd keep that appointment with the trailer and go for a drive with them. They may be able to monitor everything going on while you try and duplicate your issues.

Link to comment
Share on other sites

I took my 8000lb travel trailer through the rockies this summer with my 2016 lml. didn't really push it last 65 or so but never had an issue keeping up that speed. Not the same, but it always felt like there was more if I ever needed it. Never felt that I was out of power.


good luck sir. interested to see how the drive goes on 11/16.

Link to comment
Share on other sites

Guy, Thank you for the replies this far. I am glad to see my story is being read.

 

I had my appointment with the dealership yesterday. I had a mechanic do a ride along so I could duplicate the issue. Sure enough I was able to duplicate the problem. He had a laptop hooked up to the truck and as we went along he said everything on his screen looked normal. I was able to pull a hill in drive and it would only shift from 6th to 5th. Unless I used manual mode or cruse I was stuck in 5th trying to accelerate from 68-70 mph up hill pulling a trailer in tow haul mode. He agreed there seems to be an issue. He initial response was that the transmission is not being told to shift down from 5th to 4th. If I force it into 4th gear the truck does takes off and picks up speed going up an incline. That is the only way I can increase speed.

 

The mechanic was going to go back and read up on the tow haul mode and see if he could find out why it is not shifting. Further more he is going to call GMC tech support and talk to them about this issue. I am waiting on the dealership to call me back with some news. As the saga continues I will report back to the group. Thank you again for reading my posts.

Link to comment
Share on other sites

  • 1 month later...

If you watch the fast lane truck tests on YouTube you will find that pretty much all these new trucks have this issue now, they always talk about in their videos how the trucks won't shift to lower gear for more power...

 

The gas Rams were awful at this... At least the Chevy's have the manual switcher...Some of the trucks don't even let you do that, so you are really stuck in 5th...

Link to comment
Share on other sites

  • 1 month later...

 

 

My 2015 pulls a load without your issues. Have a new one on order.

 

Please post the final results. Trust the mechanic knows trucks and does not commute in a Yugo and read the manuels and drink coolaid. Your experience hopefully is an uncommon one which has been resolved

 

As far a def consumption it seems about right. Since I get over 5000 miles on a tank today the increased tank size in the 2017 has me wondering why.

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

  • Recently Browsing   0 members

    • No registered users viewing this page.
  • Forum Statistics

    245.8k
    Total Topics
    2.6m
    Total Posts
  • Member Statistics

    333,234
    Total Members
    8,960
    Most Online
    Donald Dolan
    Newest Member
    Donald Dolan
    Joined
  • Who's Online   3 Members, 0 Anonymous, 693 Guests (See full list)



×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.