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HELP - Do I have a truck problem of just not enough truck

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  • HELP - Do I have a truck problem of just not enough truck

    Hello: I know that many of you are pulling a similar rig with an F350 Dually. Can you tell me if what I am experiencing is normal for my set up or do I have a problem with my truck? I'll post this over in diesel forums also. Ford dealer has not been able to help.

    My set up:
    2013 F350 Dually Diesel, 6.7 litre, 3.73 limited slip axle ratio
    2014.5 38 RESB3 at 20,400 while fully loaded for extended travel and max per towing guidelines is 22,200
    GCW of truck and Suite is 30,800 and max GCWR per Ford towing guidelines is 30,500
    Per Ford towing guidelines, I am in spec for fifth wheel towing

    So we did about 6000 miles on our last road trip and experience difficulty on 3 memorable occasions. By difficulty I mean the temp came up to about two-thirds but did not redline and no, I did not get the actual reading. Something else came on, perhaps a fan, made a bunch of noise. I cannot tell for sure if the temp went up first or the noise came up first. Transmission was in auto not manual. Bogged down to about 2nd gear and about 15 MPG in the two towing situations described below.

    Towing:
    o I-95 between North Carolina and West Virginia. Very moderate hills; I saw no reason for this rig to drag.
    o I-25 Colorado to New Mexico going up the Raton Pass to 8000 feet; monster climb with the rig really bogged down.
    Bobcat…not towing
    o I-70 leaving Denver and climbing up to Loveland was 10 miles of steep grades. We went to visit a friend w/o the RV and wanted to stay in an RV park south of them. After making the trip up w/o the RV, we changed our trip plans as I was certain we would not make it up the mountain with the RV.

    I did what I thought was extensive research to match the truck to the RV and thought I was well within spec and would not have a problem. I love the truck and the rig. However, we are just getting started with RVing and have never towed before. We do anticipate going to full time in 2-3 years and I do not want to have to worry about having enough truck. Think Alaska!

    I'd really appreciate some advice from those of you with a similar set up and personal experience on similar mountain grades. Oh, I also recently had a turbo replace but they said that would not have any impact.

    Thanks so much.
    Last edited by moeandflo; 02-27-2015, 01:55 PM.
    Michael and Katherine (Moe and Flo on the go)
    Full-time since March 2017

    2016 F450, DRW, Crew Cab, Goodyear airbags, TrailerSaver TSLB2H hitch
    2014.5 Elite Suites 38RESB3, vanity slide, customized. #6987

  • #2
    Michael,

    Do you know the axle ratio on your truck? Bogging down to 15mph, especially on that I95 trip, seems wrong. We took our rig (around 18.5k) through some very steep hills in Quebec last August and never got lower than 3rd gear. We do run with a 4.1 axle, but your 13 Ford probably has more horsepower.

    I'm not sure what happens to a Ford motor when it gets into a DPF regeneration - this can affect power output on some engines. However, if you're working the engine hard, active regens will be infrequent. The recent turbo replace may be an issue, but if the variable geometry on it (I presume that it has it) is not working properly, then I would expect to see a CEL. The noise you hear when the engine temp is high is the cooling fan operating after its clutch engages. How is your air filter? Any chance of it being clogged, or mis-installed by the dealer when the turbo was done?
    Last edited by willym; 02-27-2015, 01:21 PM.
    Bill M, Ontario, Canada
    2015 MS 38RSSA #7348.
    2009 Ram Dually Diesel, 68RFE, 4.10 axles.
    In Good I Trust

    Comment


    • #3
      Originally posted by moeandflo View Post
      Oh, I also recently had a turbo replace but they said that would not have any impact.
      Not only would a defective turbo have an impact, it could actually be the cause of your problem. To explain, due to modern emission regulations, to avoid the infamous "cloud of black soot" that people associate with diesels, the engine control unit (ECU) in your truck will not allow any more fuel to be injected than can be completely burned in the available combustion air. If the airflow (output from the turbo) decreases, maximum fuel available will decrease proportionally, and power output is a function of the amount of fuel injected. So, loss of airflow can (and will) result in reduced power, even if you don't see the tell-tale black smoke that you would see in older diesels if airflow were restricted. The ECU, in preventing overfueling, is also keeping your engine from melting down due to excessive exhaust gas temperatures (EGTs) if airflow is restricted.

      Our Cummins 6.7 runs at 201-203 degF coolant temperature while towing on the Interstate (it has a 200 degF thermostat). On long, steep grades the temperature will climb to 219 degF where the ECU turns on the engine-driven cooling fan (which does make a mighty roar) and temps drop within a minute back to the 200 degF range and the fan shuts off. This is normal operation.

      Rusty
      Last edited by RustyJC; 02-27-2015, 01:58 PM.
      Rusty & Sandy Creekmore
      2 Shelties - Coby & Callie + Conner the Campground Cat

      Prior - 2004 MS 36RE3 #1291; Current - 2014.5 MS 38RSSA #6972

      2016 Ram 3500 DRW Longhorn Crew Cab Long Bed, 4x4, 385/900 Cummins, Aisin AS69RC, 4.10, B&W RVK3600 hitch

      Comment


      • #4
        Originally posted by willym View Post
        Michael,

        Do you know the axle ratio on your truck? Bogging down to 15mph, especially on that I95 trip, seems wrong. We took our rig (around 18.5k) through some very steep hills in Quebec last August and never got lower than 3rd gear. We do run with a 4.1 axle, but your 13 Ford probably has more horsepower.

        I'm not sure what happens to a Ford motor when it gets into a DPF regeneration - this can affect power output on some engines. However, if you're working the engine hard, active regens will be infrequent. The recent turbo replace may be an issue, but if the variable geometry on it (I presume that it has it) is not working properly, then I would expect to see a CEL. The noise you hear when the engine temp is high is the cooling fan operating after its clutch engages. How is your air filter? Any chance of it being clogged, or mis-installed by the dealer when the turbo was done?
        Thank you. I corrected my post to reflect 6.7 litre, 3.73 axle. I am sorry for not being more clear. The I-95 experience did not bog down as bad but temp did go up and fan came up. The turbo was just changed last week after it began making a noise. The gas mileage appears to be better per electronics.
        Michael and Katherine (Moe and Flo on the go)
        Full-time since March 2017

        2016 F450, DRW, Crew Cab, Goodyear airbags, TrailerSaver TSLB2H hitch
        2014.5 Elite Suites 38RESB3, vanity slide, customized. #6987

        Comment


        • #5
          Originally posted by RustyJC View Post
          Not only would a defective turbo have an impact, it could actually be the cause of your problem. To explain, due to modern emission regulations, to avoid the infamous "cloud of black soot" that people associate with diesels, the engine control unit (ECU) in your truck will not allow any more fuel to be injected than can be completely burned in the available combustion air. If the airflow (output from the turbo) decreases, maximum fuel available will decrease proportionally, and power output is a function of the amount of fuel injected. So, loss of airflow can (and will) result in reduced power, even if you don't see the tell-tale black smoke that you would see in older diesels if airflow were restricted. The ECU, in preventing overfueling, is also keeping your engine from melting down due to excessive exhaust gas temperatures (EGTs) if airflow is restricted.

          Our Cummins 6.7 runs at 201-203 degF coolant temperature while towing on the Interstate (it has a 200 degF thermostat). On long, steep grades the temperature will climb to 219 degF where the ECU turns on the engine-driven cooling fan (which does make a mighty roar) and temps drop within a minute back to the 200 degF range and the fan shuts off. This is normal operation.

          Rusty
          Thank you. That helps a bit to understand what turbos do. Mileage has improved and dealer set something about the system "relearning." Also I will double-check the air filter and I am religious about 5000 mile service. Just had that too.
          Michael and Katherine (Moe and Flo on the go)
          Full-time since March 2017

          2016 F450, DRW, Crew Cab, Goodyear airbags, TrailerSaver TSLB2H hitch
          2014.5 Elite Suites 38RESB3, vanity slide, customized. #6987

          Comment


          • #6
            First of all, please understand that it's almost impossible to diagnose your specific problem over the Internet with extremely limited data. Having said that, let me give you a couple of possibilities:

            1. You didn't mention how your first turbo failed. If it had a bad seal, it would leak oil from the bearing cavity into the compressor section where it could pool in the intercooler (a charge air cooler positioned between the turbocharger air outlet and the engine air inlets.) If that was the mode of failure, and if the dealer didn't flush the intercooler thoroughly when he changed the turbo, the accumulated oil could restrict airflow. It also represents a significant risk for your engine as, if it were carried over into the engine intake manifolds, you'll find that a diesel engine will run quite happily on engine lube oil - to the extent that it can actually run away!

            2. If your problem is more severe at higher altitudes, this could be a sign that the new turbo isn't functioning correctly. To explain, a turbocharged engine should hold its sea level power rating at higher altitudes (Cummins engines, for instance, hold their sea level ratings up to 10,000 ft elevation). This is due to the self-correcting nature of the way a turbocharger compresses air. As you go higher in altitude, air density (the mass of air in a given volume - pounds per cubic foot, for instance) decreases. This unloads the turbocharger's compressor impeller, so the turbocharger compensates by spinning faster, thereby compressing more cubic feet of the less dense air, so mass flow (pounds per minute) of the combustion air will remain constant. This will take place until the turbocharger reaches its maximum allowable speed - the Cummins turbos are sized for 10,000 ft altitude; I'm not sure how Ford sized the 6.7L PowerStroke turbo. If the turbo can't spin up properly due to sticking or otherwise malfunctioning variable nozzle guide vanes or other problems, the mass of air compressed by the turbocharger will decrease with altitude, and less air means less power.

            A competent diesel mechanic (not a parts-changer) with the right equipment should be able to diagnose your loss/lack of power problem fairly readily.

            Rusty
            Rusty & Sandy Creekmore
            2 Shelties - Coby & Callie + Conner the Campground Cat

            Prior - 2004 MS 36RE3 #1291; Current - 2014.5 MS 38RSSA #6972

            2016 Ram 3500 DRW Longhorn Crew Cab Long Bed, 4x4, 385/900 Cummins, Aisin AS69RC, 4.10, B&W RVK3600 hitch

            Comment


            • #7
              Originally posted by RustyJC View Post
              First of all, please understand that it's almost impossible to diagnose your specific problem over the Internet with extremely limited data. Having said that, let me give you a couple of possibilities:

              1. You didn't mention how your first turbo failed...

              2. If your problem is more severe at higher altitudes, this could be a sign that the new turbo isn't functioning correctly. ...

              A competent diesel mechanic (not a parts-changer) with the right equipment should be able to diagnose your loss/lack of power problem fairly readily.

              Rusty
              Thank you Rusty. The turbo started making a grinding noise and had a bearing failure. This is well after the trip problems I described and since that trip I have been doing the flat-lander thing. I wouldn't say that the problem is due to altitude as the problem presents at the bottom of the hill and I don't believe I was ever much over 8500 feet. If I understand you last comment, I think you are saying to take the truck somewhere other than the Ford dealer. I thought of that. As I said, where we live, super-duty pickups are not the norm.

              Thanks again for your thoughts.

              Also I'd really like to hear from anyone who has pulled a similar rig with similar equipment up I-70 or through the Raton pass. What was your experience???
              Michael and Katherine (Moe and Flo on the go)
              Full-time since March 2017

              2016 F450, DRW, Crew Cab, Goodyear airbags, TrailerSaver TSLB2H hitch
              2014.5 Elite Suites 38RESB3, vanity slide, customized. #6987

              Comment


              • #8
                I'm a little confused by your chronology. If the problems existed on the failed turbo, are you sure that they still exist with the new one?

                Rusty
                Rusty & Sandy Creekmore
                2 Shelties - Coby & Callie + Conner the Campground Cat

                Prior - 2004 MS 36RE3 #1291; Current - 2014.5 MS 38RSSA #6972

                2016 Ram 3500 DRW Longhorn Crew Cab Long Bed, 4x4, 385/900 Cummins, Aisin AS69RC, 4.10, B&W RVK3600 hitch

                Comment


                • #9
                  Originally posted by RustyJC View Post
                  I'm a little confused by your chronology. If the problems existed on the failed turbo, are you sure that they still exist with the new one?

                  Rusty
                  Rusty: Well, the trip was last June and July and I had no indication of a failed turbo until about a month ago when I started to get a small rubbing noise when idling down. I guess the turbo could have been back last summer but I started out the trip with less than 6000 miles on the truck. I just had the turbo fixed last week so no, I don't know if that did or did not fix the problem. All I know for sure is that the Ford dude said it would have no impact.

                  Thank you for you patience. I am not a mechanic, I am not mechanically inclined, and up until July of 2013 I couldn't spell deesull.
                  Michael and Katherine (Moe and Flo on the go)
                  Full-time since March 2017

                  2016 F450, DRW, Crew Cab, Goodyear airbags, TrailerSaver TSLB2H hitch
                  2014.5 Elite Suites 38RESB3, vanity slide, customized. #6987

                  Comment


                  • #10
                    OK, if the old turbo was failing, that could have caused the problem - the rub and failing bearing would not allow the turbo to come up to speed. I'd give it a try with the new turbo and see if the low power problems still exist.

                    Rusty
                    Last edited by RustyJC; 02-27-2015, 08:06 PM.
                    Rusty & Sandy Creekmore
                    2 Shelties - Coby & Callie + Conner the Campground Cat

                    Prior - 2004 MS 36RE3 #1291; Current - 2014.5 MS 38RSSA #6972

                    2016 Ram 3500 DRW Longhorn Crew Cab Long Bed, 4x4, 385/900 Cummins, Aisin AS69RC, 4.10, B&W RVK3600 hitch

                    Comment


                    • #11
                      Mo-
                      I have a 2008 F450 and pull a 36 TKSB at 19,500. I have had the exact same thing happen to my truck, first time coming out of Knoxville into Virginia and the second time coming out of Salt Lake City. I have 4 electric cooling fans and when the ECU sees either a high transmission temp or the water temp raises past the normal range and they kick in - it sounds like a jet plane taking off !! The power loss is again the ECU protecting the engine from a melt down due to hot air in the intake being less dense going into the turbo and the demand from your throttle position saying give me max power. I only dropped to 45 MPH and after a few minutes was able to go back full power. Four more years of pulling and no problem with the engine or turbo so not related to your turbo problem.
                      John & Bonnie Mc Clun
                      2008 F-450 King Ranch Dually
                      2011 MS TKSB3 #5793
                      http://drv-owners-manual.com

                      Comment


                      • #12
                        Michael,

                        I may not be much help to you, since most have helped you with the turbocharger issue. Jo and I went over Raton Pass back in mid-July and had no problems like yours. I might have slowed down a bit, but still was above 50 mph at the top. However, we have a 2008 F450 as well and ours has both the Tow/Haul feature and the 4:88 rear differential ratio.

                        Since I don't know how the newer trucks are equipped, does your model have the Tow/Haul feature. If you do, be sure and use that on both the uphill and downhill sides of mountain passes. That feature somehow "reconfigures" the transmission in some way to work better for pulling and for helping keep one's speed down on the downhill side. The Tow/Haul, if yours has it, may not need to be engaged when in pretty flat country. How did your truck handle in the flat country? If it seemed to keep you pretty slow, maybe it needs to be engaged whenever you are towing, regardless of terrain.

                        Your 3:73 differential ratio could be a factor as well, especially for the uphill grades. When I drove 18-wheelers, one of them had a 5:29 differential ratio while many others had 4:11's. Those guys would fly by me out on the flats, but when we got into hills, my truck would outperform theirs.

                        Terry
                        Terry and Jo

                        Mobile Suites 2010 38TKSB3 #5332
                        2008 Ford F450
                        2017 Ford Expedition XL as Tag-along or Scout

                        Our Photos on Smugmug

                        Comment


                        • #13
                          You have enough truck, just the 3.73 is a little high for 20K weight. Fan noise is normal, sounds pretty bad when it comes on--when it kicks in, you should be able to notice the temp gauge coming down just a little. Never moves under normal temps, but if you hear the fan kick in, you should be able so see some movement on the gauge. But at this point, you don't know if the problem still exists, as you haven't pushed it since the repair?
                          Joe
                          2005 36TK3 #1869
                          2010 F450 Lariat

                          Comment


                          • #14
                            Get a turbo boost gauge installed on the truck...I am sorry I can't help you with your problem but I would think your truck could handle that 5th wheel weight...The turbo should have been singing when you had that problem pulling that hill and you should have been able to here the sound and pitch of the turbo...I have a 1 ton Ram 3500 DW with the 6.7 Cummins and 3.73 gear..My 5th wheel is a 38RSSB3...The largest hill I have ever had to pull up so far is on I70 west a couple miles east of Cumberland Md. and it is quite steep and long I was able to pull that hill at 60MPH and the truck had plenty left if I wanted to go faster...

                            Comment


                            • #15
                              Originally posted by carson54 View Post
                              Get a turbo boost gauge installed on the truck...I am sorry I can't help you with your problem but I would think your truck could handle that 5th wheel weight...The turbo should have been singing when you had that problem pulling that hill and you should have been able to here the sound and pitch of the turbo...I have a 1 ton Ram 3500 DW with the 6.7 Cummins and 3.73 gear..My 5th wheel is a 38RSSB3...The largest hill I have ever had to pull up so far is on I70 west a couple miles east of Cumberland Md. and it is quite steep and long I was able to pull that hill at 60MPH and the truck had plenty left if I wanted to go faster...
                              Thank you Carson. Might I ask the weight of your rv?

                              Regards.
                              Michael and Katherine (Moe and Flo on the go)
                              Full-time since March 2017

                              2016 F450, DRW, Crew Cab, Goodyear airbags, TrailerSaver TSLB2H hitch
                              2014.5 Elite Suites 38RESB3, vanity slide, customized. #6987

                              Comment

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