Thanks for all the replys,that gives me a good idea of what to expect.I will need to do all of the nessary precautions with watching weight as far as loading and getting to the scale to get accurate weight.
I have an '02 D'max, with the 5-speed Allie and no way to manually select 4th (thanks to some brilliant exec at GM). When I hit mountain grades here in AZ, and am running heavy, I have no real choice but to let it drop into 3rd, and run it at about 2500 rpm, which translates into about 45 mph. No real reason to push it any more than that, though I could. I also run my Banks Bullet in Tow Mode, which does add about 15 hp, but I've never had any temp issues at this speed.
Lyle
2002 GMC Sierra 2500 HD Duramax Crew Cab 4x4
Banks Bullet Tuner and Monster Exhaust
B&W Turnover Ball with 5th Wheel Companion
2004 Komfort 25FSG Fifth Wheel
1936 John Deere Model A
International Flying Farmers 55 Year Member
Not towing by with 4000 lbs in the bed running up 6% grade was no different then flat ground for the Duramax (2 weeks ago and temps were 90+. As for the temps jumping up mine has never done that. And its the first month LLY 2004 1/2. Pull 5 mile 6% with 4000lb Truck camper and towing 3000lb boat. Never had that issue.
Also same motor/trans and rear end does not matter if its 2500 or 3500.
Pete
2004 Duramax/allison Trans C/C 4x4
2012 Landmark Key Largo
2008 Lund 1825 Pro Guide Tiller, With a Evinrude 90 HP E-Tec
When do you use it, not use it? Around town, hills? I noticed that when I turn the OD off, the engine seems to be working super hard. I felt like it made the engine much hotter.
DH thinks we need to use it everytime we are in town and then once we hit 60 mph, we can turn it on again.
I personally don't really like it because I think it drops the MPG horribly. Maybe to get off from a start a little faster?
Sorry about the newbie question, just curious. Thank you.
2012 GMC 3500HD, Diesel, Crew Cab Standard Bed, SRW
2013 Cyclone 3010 (to be picked up)
porkchop1221 wrote: I have a question regarding overdrive.
When do you use it, not use it? Around town, hills? I noticed that when I turn the OD off, the engine seems to be working super hard. I felt like it made the engine much hotter.
DH thinks we need to use it everytime we are in town and then once we hit 60 mph, we can turn it on again.
I personally don't really like it because I think it drops the MPG horribly. Maybe to get off from a start a little faster?
Sorry about the newbie question, just curious. Thank you.
My experience is to turn on Tow Haul and let the truck select the gears. Some will manually shift but I have had no problem just putting it in drive and letting the truck figure it out.
porkchop1221 wrote: I have a question regarding overdrive.
When do you use it, not use it? Around town, hills? I noticed that when I turn the OD off, the engine seems to be working super hard. I felt like it made the engine much hotter.
DH thinks we need to use it everytime we are in town and then once we hit 60 mph, we can turn it on again.
I personally don't really like it because I think it drops the MPG horribly. Maybe to get off from a start a little faster?
Sorry about the newbie question, just curious. Thank you.
Are you talking about towing or not towing? When empty, I run my D'max in "normal" mode and let the 'puter decide what to do. I will run about 50-52 on some streets as that's where the Allie goes into OD. In T/H mode, even empty, I won't hit O/D until about 60. When I'm on the flat, and towing, I'll turn T/H mode =off= so it'll shift into OD; with T/H mode on, even a very slight grade, or a headwind > ~10-15 mph will cause me to drop into 4th, and stay there. As soon as I see a grade coming, I'll turn T/H back on and let the tranny work as it's supposed to. (Lately, I've been towing at 60 mph, but will bump to 65 as-needed. My wallet thanks me for this.) As I can not =manually= turn off OD, short of shifting directly to 3rd, it's a fairly moot point for me, anyway.
Towing really. We just got the Cyclone on Friday and did the drive home on Saturday and Sunday.
We were told to turn on the "towing" mode which I think turns OFF the overdrive? On small streets and once we are going, on a highway, to turn the towing mode off to "normal".
I was in overdrive going 60 MPH but on the backroads. DH turned the towing button on and I felt like we were on very high revs that we didn't need. When we stopped I felt like the engine was 'hot' and I personally didn't want to be in that mode unless NEEDED.
Its all new to me so I'm not sure what we are doing. At all.
porkchop1221 wrote: Towing really. We just got the Cyclone on Friday and did the drive home on Saturday and Sunday.
We were told to turn on the "towing" mode which I think turns OFF the overdrive? On small streets and once we are going, on a highway, to turn the towing mode off to "normal".
I was in overdrive going 60 MPH but on the backroads. DH turned the towing button on and I felt like we were on very high revs that we didn't need. When we stopped I felt like the engine was 'hot' and I personally didn't want to be in that mode unless NEEDED.
Its all new to me so I'm not sure what we are doing. At all.
The computer is pretty smart, so most really just let it do its thing. Turn on T/H mode, put in D and go! :-) Again, if you're on the flat, and not traveling too fast, you might want to turn off T/H mode so it will kick into OD at a lower speed. Most times, if you turn it back on, it will stay in OD until you hit a grade or accelerate. Don't forget that T/H mode also kicks in when =decelerating=, and causing the tranny to downshift automatically. Very, very handy. :-)
porkchop1221 wrote: Towing really. We just got the Cyclone on Friday and did the drive home on Saturday and Sunday.
We were told to turn on the "towing" mode which I think turns OFF the overdrive? On small streets and once we are going, on a highway, to turn the towing mode off to "normal".
I was in overdrive going 60 MPH but on the backroads. DH turned the towing button on and I felt like we were on very high revs that we didn't need. When we stopped I felt like the engine was 'hot' and I personally didn't want to be in that mode unless NEEDED.
Its all new to me so I'm not sure what we are doing. At all.
No,tow/haul has NO effect on your overdrive whatsoever. All it does is change the RPM at which the transmission shifts to a somewhat higher level in each gear.
As long as your gear selector is in Drive, it will shift as necessary, and once it shifts out of fourth gear,you are then in overdrive in both fifth and sixth gear.
As far as your engine being 'hot' when towing with tow/haul engaged,it is not, unless something is drastically wrong with your truck.If your truck was actually over heating you would know it, as your driver information center would display a message to that effect.
I use tow/haul whenever I have my fifth wheel hooked to the truck, and leave it there, whether on city streets, or on the highway.
The best thing for you to do for your own peace of mind, is get out the owner's manual for your truck, and go through the towing section carefully. It will explain what you need to know.
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