Struggles to pull hills with 12k lb 5er - Diesel Place : Chevrolet and GMC Diesel Truck Forums
 
Home Forum Market Place Garage Tuning Library DTC Tool Register Vendors
Go Back   Diesel Place : Chevrolet and GMC Diesel Truck Forums > Speciality Forums > Towing
Register FAQ Forum Rules My Replies My Threads Mark Forums Read Advertise

Towing Discuss Anything Related To Towing With Your Diesel. Any RV-specific discussions belong here.

DieselPlace.com is the premier Duramax Diesel Forum on the internet. Registered Users do not see the above ads.
Like Tree4Likes

Reply
 
LinkBack Thread Tools
Old 08-07-2015, 04:14 PM   #1 (permalink)
NorCal2500HD
Diesel Head
 
Join Date: Dec 2005
Posts: 701
iTrader Score: 0 reviews

Struggles to pull hills with 12k lb 5er

Looking for feedback from others who tow similar size/weight trailer. I just returned from a 1000mi trip towing my 5er and the truck (2012 stock LML) got the job done but just didn't impress me holding speed on hills or mileage. I was running 63-67ish MPH the entire trip and on some hills it struggled to hold 60MPH and even downshifted all the way down into 3rd on a couple of grades and just held there pinned at ~55MPH to the top of the grade. I have a CTS and the truck was making boost ~26PSI but just felt weak to me. I was monitoring my throttle input on the CTS much of the trip and just to hold speed on flats I was 45-50% throttle in 5th (I don't use 6th towing...) and on every grade I had to really get into it 80-90%+ just to hold speed.

Having never driven another Dmax with this type load I don't know if my experience is normal or not. Oh and I averaged just under 9MPG hand calculated.


Last edited by NorCal2500HD; 08-07-2015 at 04:15 PM.
Offline  
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
Old 08-07-2015, 05:11 PM   #2 (permalink)
97chevor
Diesel Boss
 
97chevor's Avatar
 
Join Date: Aug 2012
Location: US/Canada
Posts: 1,476
iTrader Score: 0 reviews

Yeah, get above a 10k camper in the mountains the truck becomes underpowered. It's normal.

__________________
2010 Gmc 2500 Duramax 853,500 miles - sold
2010-gmc-2500 maintance log
2013 Chevy 3500 LT CCSB, bought at 509,000 miles, now over 660,000 miles
2013 LT CC & Chassis with 9' Hillsboro Aluminum flatbed - under 84,000 miles - sold

Favorite book : The Richest Man in Babylon
Offline   Reply With Quote Quick reply to this message
Old 08-07-2015, 05:17 PM   #3 (permalink)
heymccall
Diesel Elite
 
heymccall's Avatar
 
Join Date: Feb 2005
Location: Butler county, PA USA
Posts: 17,729
iTrader Score: 0 reviews

Put it in tow/haul and D. You cannot hurt the transmission by leaving it in D (using 6th when the truck sees fit).
Stock tire size?
How much air in tires?
How big of a profile on trailer?

The only reason to go manual is if you feel it shifting 5/6 too often (hunting). Its a diesel. The torque is most usable at lower RPMs than in a gas truck.
__________________
Brian
'13 Hyundai Genesis Coupe handshaker
'14 Peterbilt 337 handshaker
Quote:
Originally Posted by GetSome8.1HD
Its not like I said I enjoyed reading Good Housekeeping while taking a candle lit bubble bath then proceeding to using a loofah with exfoliating creams all while thinking about you . Now THAT would be creepy
Member #21 of the OiO association

Last edited by heymccall; 08-07-2015 at 05:20 PM.
Offline   Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
Old 08-07-2015, 08:29 PM   #4 (permalink)
Sturgeon-Phish
Diesel Boss
 
Sturgeon-Phish's Avatar
 
Join Date: Sep 2009
Location: Portsmouth Ohio
Posts: 1,373
iTrader Score: 0 reviews

Is the 12K actual weight of the camper or what the camper is rated? It is amazing how much stuff we pack and can add weight quickly and weight is a huge factor.
Jim
__________________
2003 GMC 3500 crew dually LB7 NF2 Federal. Onyx Black, Dark Tint & De-badged, Transfer Flow 50g aux tank; Pace Edwards power tonneau. Isspro EGT & Boost. PPE Boost Valve. Mich. LTX A/T2 LT215/85R16. CTS Insight with backup camera, Air Box mod, Stock exhaust no muffler, Fumato drain valve. B&W turnover with Companion 5th wheel platform, Line-X. Hi/Low Beam light mod. 80 watt LED backup lights . Kennedy Single Pump & Fuel Pre-filter (Thanks John). Weather Tech mats. MA Pump Upgrade with new T case rear half. LDS injectors (Thanks Brent). High Idle mod (Thanks Eric) Hopkins Easylift. Pulls a '05 Wildcat 31QBH 5th wheel. Member #1078 3500 Dually Club
Offline   Reply With Quote Quick reply to this message
Old 08-07-2015, 08:52 PM   #5 (permalink)
IGO1320
Diesel Superstar
 
IGO1320's Avatar
 
Join Date: Sep 2007
Location: Apopka Florida
Posts: 3,587
iTrader Score: 0 reviews

I also prefer to leave mine in manual fifth when towing heavy. It will normally hold speed up most hills easier. I have an 80hp tow program that works really well and the EGT's stay in check. When descending I will bump it down to fourth if the hill is steep, if the speed limit is 45-55 generally I have to use third. With the turbo brake and engine braking I rarely have to use the brakes during a decent.
__________________
2006 2500HD CCSB 4X4 RED LBZ
Spray-In Bed Liner, Air Bags
Custom Reese 20K slider FWH/Gooseneck hitch
265/75/16 Michelin LTX AT2's on PYO's
Duramax.com tow tune w/turbo brake
PPE Dual Fueler (P0087 cure)
Kitty on a "warm shelf", K+N Drop-in filter
Amsoil in all places, Amsoil BMK-27 Bypass
KYB shocks (stock sucked)
Autometer Boost/Pyro gauges/Edge CTS
EGR blocker and (Kennedy) finger stick
Merchant remanufactured transfer case 748,000
Kennedy lift pump, reserve tank with transfer pump
Suncoast trans and 1700 stall converter @ 748,000
14.558 @ 91.03 Hypertech now?????
Offline   Reply With Quote Quick reply to this message
Old 08-07-2015, 10:35 PM   #6 (permalink)
NorCal2500HD
Diesel Head
 
Join Date: Dec 2005
Posts: 701
iTrader Score: 0 reviews

I typically tow in D with T/H an EB on. Trailer is a 30ft 5th wheel Toyhauler with a dry weight of 9k lb and a 12k lb GVWR.
Offline   Reply With Quote Quick reply to this message
Old 08-09-2015, 10:26 PM   #7 (permalink)
turnpike
Diesel Champ
 
turnpike's Avatar
 
Join Date: May 2004
Location: Alberta/Arizona
Posts: 1,961
iTrader Score: 0 reviews

NorCal2500HD.... what RPM are you running?

I find that over 2500 RPM you can go full throttle, it may not shift up a gear, and you burn a lot of fuel and not get anywhere. Unless you are drag racing, gas engine type RPM is harmful to a diesel. Slow the engine down and let the torque do the work.

I prefer to go in Drive, T/H set, cruise set at 65, and let her run.

If you have to manually control it then easy off the throttle when you can and allow it to shift up. Run it between 2000 and 2500 RPM to get the advantage of the torque a diesel has. In fact if it wants to run 1800-2000 in "D"rive, T/H set, let it do it. If it seems to lug (doesn't respond to throttle up), kick it down a gear so it comes in at about 2300. Makes a lot easier driving experience. Burns less fuel and runs cooler.
__________________
Turnpike

'16 Chev 2500HD LTZ Z71, CC, Duramax, Allsion, 4wd, new Sept 2016, has factory fifth wheel prep so added a Curt hitch.

Traded off-'05 Chev, 2500HD, CC, SB, Duramax, Allison, 4WD, bought new April '05, sold at 179,400 miles, LBZ mouthpeice, Blocker Plate & Unplugged EGR, Air Box cut out, lost the cat, 52 US Gal (196 Litre) Titan Fuel Tank, SuperChips tuner reset to stock and retained, AirLift air bags, BrakeSmart Trailer Brake controller, PaceEdwards cover-replaced 2013, DSP Fifth Hitch, JVC KW-NT1 headunit, kept the"AutoEnginuity" scanner.

'02 GMC, 2500HD, CC, SB, D/A, 4wd, Traded in - wrong color
Offline   Reply With Quote Quick reply to this message
Old 08-11-2015, 10:23 PM   #8 (permalink)
turnpike
Diesel Champ
 
turnpike's Avatar
 
Join Date: May 2004
Location: Alberta/Arizona
Posts: 1,961
iTrader Score: 0 reviews

More thoughts for you to consider.

Throttle percentage is a product of power needed. Mine with a bit less torque will often run over 50 percent. And on the hills it would go to 100%. Keep in mind there are Interstate roads that will bring you down to 30 MPH. Also slows any other large vehicles, such as semis, buses, and motor homes. If you are down to 30 MPH, don't kick it down into first gear because that unlocks the convertor and heats the trany.

I don't post my fuel mileage because it is never the same twice when pulling a trailer.

There are many variables to the power equation, such as wind, trailer profile, weight and road grade. I think wind speed and direction to your travel is the greatest factor to miles per gallon. Consider you are pulling a unit as high and wide as a semi trailer with only 700 -750 pound feet of torque. Semis may have up to 2200 pound feet of torque and four times the cost. So when they are empty, if you can run with them in the hills you are doing pretty good. Speaking of torque, the Duramax gives peak torque at about 1650 RPM according to GM's specs.

So, you may wish to work the engine closer to the peak torque RPM. I think you may find it will use less fuel. That may not peak the hills at the maximum speed but you may find the saving worth while. If you kick or select it down a gear you move away from the peak torque, and may use more fuel. The Allison trany is super at selecting the correct gear, and that is why we suggest, put in Drive, set Tow/Haul and go. I do drive more by the tach than the speedo until I get up to speed.

I hope this helps you consider how us old time semi drivers have learned to run. Some may call it differently, but we aren't in it to win the race, just get there safe and efficiently, while enjoying the ride.

I don't wish to rain on your parade. We have all been there, done that, and learned from it. Let us know how your next trip goes.
__________________
Turnpike

'16 Chev 2500HD LTZ Z71, CC, Duramax, Allsion, 4wd, new Sept 2016, has factory fifth wheel prep so added a Curt hitch.

Traded off-'05 Chev, 2500HD, CC, SB, Duramax, Allison, 4WD, bought new April '05, sold at 179,400 miles, LBZ mouthpeice, Blocker Plate & Unplugged EGR, Air Box cut out, lost the cat, 52 US Gal (196 Litre) Titan Fuel Tank, SuperChips tuner reset to stock and retained, AirLift air bags, BrakeSmart Trailer Brake controller, PaceEdwards cover-replaced 2013, DSP Fifth Hitch, JVC KW-NT1 headunit, kept the"AutoEnginuity" scanner.

'02 GMC, 2500HD, CC, SB, D/A, 4wd, Traded in - wrong color

Last edited by turnpike; 08-11-2015 at 10:27 PM.
Offline   Reply With Quote Quick reply to this message
Old 08-12-2015, 09:07 PM   #9 (permalink)
IGO1320
Diesel Superstar
 
IGO1320's Avatar
 
Join Date: Sep 2007
Location: Apopka Florida
Posts: 3,587
iTrader Score: 0 reviews

I have an 06 so when towing heavy at a speed of 65 or less I use fifth. Lighter trailers I will let it go to sixth which is about 65 with my truck. My tow rpm is generally 1750-1900 rpm. I have hundreds of thousands of miles towing with this truck and I can generally get 10-12 towing most trailers assuming no head wind. The big triple axle trailers generally are 9-9.5 again assuming no big wind.
__________________
2006 2500HD CCSB 4X4 RED LBZ
Spray-In Bed Liner, Air Bags
Custom Reese 20K slider FWH/Gooseneck hitch
265/75/16 Michelin LTX AT2's on PYO's
Duramax.com tow tune w/turbo brake
PPE Dual Fueler (P0087 cure)
Kitty on a "warm shelf", K+N Drop-in filter
Amsoil in all places, Amsoil BMK-27 Bypass
KYB shocks (stock sucked)
Autometer Boost/Pyro gauges/Edge CTS
EGR blocker and (Kennedy) finger stick
Merchant remanufactured transfer case 748,000
Kennedy lift pump, reserve tank with transfer pump
Suncoast trans and 1700 stall converter @ 748,000
14.558 @ 91.03 Hypertech now?????
Offline   Reply With Quote Quick reply to this message
Old 08-13-2015, 09:19 PM   #10 (permalink)
cgreen
Diesel Expert
 
Join Date: Jul 2005
Location: North georgia
Posts: 2,882
iTrader Score: 0 reviews

Georgia Diesel Owners Club Member

What percent grade was it? I've found that over 6%, you will lose speed with 10k lbs or more, but under, you should be able to hold 65 easy. That's with my LBZ on EFI tow tune, which should be very close power wise to your LML.

__________________
Sold my 2006 dually.
2011 GMC Sierra Denali now with 6.2.
Offline   Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Diesel Place : Chevrolet and GMC Diesel Truck Forums forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

PLEASE READ! You must check your email inbox for the confirmation link to complete registration. Please check your spam box if you do not see the email in your inbox.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:
Insurance
Please select your insurance company (Optional)

Log-in


Thread Tools

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Battery or starter? She starts but struggles dougydeezel 6.5L Diesel Engine 32 08-04-2013 02:12 AM
Duramax struggles brentheman Duramax Second Generation: 2004.5-2005 (LLY) 1 09-18-2011 11:12 AM
01 rclb 2500hd 12k zerogravity58 Closed / Archived Marketplace Ads 11 09-04-2011 08:25 AM
<$12K Diesel buckshot1224 Closed / Archived Marketplace Ads 2 02-25-2010 03:10 PM


All times are GMT -4. The time now is 01:44 AM.


Powered by vBulletin® Version 3.8.8
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
SEO by vBSEO 3.6.1
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Shoutbox provided by vBShout v6.2.1 (Lite) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd. Runs best on HiVelocity Hosting.
© AutoGuide