With the ratios on the 6 speed tranny it is pretty much dead on equivalance to 4.10 in the regular 4 speeds. Ring&Pinion gearing is only half the equation. Don't just assume because it has a Ring&Pinion gear of 3.42 that the "final" ratio is 3.42.
Guys, when you are in direct drive, which has normally meant OD off you are 1:1 to the rear gears. That means the engine spins 3.42 times per wheel revolution in direct drive with OD off. 3.42 is 3.42. Does the TV have 3rd or 4th gear as drive? I would not expect drive to be 5th gear. And if the guy with the same truck and driveline says it works, then it works! It sounds like a great power plant, that might grunt a little in the Rockies. If it does, go get some 3.73 gears or 4.10's.
05 F150 FX4 Supercrew, 5.4, 3.73 LS, Jordan Ultima 2020 Brake Controller,
04 TrailCruiser 30QBSS, Battery Disconnect,
Dual Cam HP, Ultra Fab Power Tongue Jack, Bal Lockarm Stabilizers
You say your future TT will be 7900 lbs. I'll guess that is dry. So by the time you load it up and have all the goodies that's another 1,000 lbs. on a big trip.
I too live in the West and know every mountain range. Bottom line, you need a diesel. Sure it will make it up the hills and 400 HP and 400 FT.lbs. sounds great, but if you want to do it right you'll need the diesel.
I'll bet right now you can buy a very sweet GM with the diesel package that is just as sweet as the gasser you are looking at. You'll be able to sit back, put it in cruise control and get the job done right. Not to mention it will be ready for the next series TT after that one...
I own a 2008 Sierra Denali AWD and tow with it. I agree with much of what is being said. This is an excellent tow vehicle. The 6-speed in tow/haul mode really sets this truck ahead of most of the competition. Just a few examples. When you apply the brake for a second, it will downshift. If you stay on the brake and the hill is steep, it will grab a lower gear. Then the fuel is cut-off totally to the engine and you can really feel it hold back. The net result is hardly even using any brakes, even down an 8% grade. My trailer brakes weren't adjusted up high enough and I was still amazed at how little I was on the brake on the Hope-Princeton. If you flick the turn signal lever for a lane change, you get 3 flashes. In tow-haul mode, you get 6 flashes. The ABS with "roll-over avoidance" even functions differently in tow-haul mode to compensate for a trailer. I could write pages but you get the idea of how much design went into this.
1st gear is really deep. You can launch up a steep hill with no problem so forget the conventional wisdom about 3.73 or 4.10 gearing - not needed. 5th and 6th are both over-drives. When you put it in tow-haul mode, 6th is locked out. My trailer is light, probably 4300 loaded, so sometimes I put it in manual mode and use the thumb shift to select M5. I don't need the high shift points on the flat with this trailer. In manual mode, it will shift normally up to whatever gear you've selected and stop there. It's very handy.
That all said, I would limit the trailer to 6500 lbs if you're going to tow a lot in the mountains. In other forums, SD owners have reports it tows well up to the limit but that's mostly on flat eastern highways. It's a lot of weight for a truck with this suspension. I would look for something lighter such as one of the new Starstreams.
I don't agree with needing a diesel. A Sierra Denali is fast and nimble. If you're going to use this truck for other things than camping, you'll appreciate the manners. I took a test drive in a 2008 HD GMC with the Isuzu/Allison combo. Too much of a tank for zipping around town. Despite all that torque, it's not even remotely as fast the Denali which does 0-60 in just over 6 seconds.
Your stat's are little off. It's 403hp, 417ft lbs torque. 8400 towing 2WD, 8200 for an AWD. The factory hitch is 1000lbs tongue/10,000lbs tow.
MQQSE wrote: You say your future TT will be 7900 lbs. I'll guess that is dry. So by the time you load it up and have all the goodies that's another 1,000 lbs. on a big trip.
I too live in the West and know every mountain range. Bottom line, you need a diesel. Sure it will make it up the hills and 400 HP and 400 FT.lbs. sounds great, but if you want to do it right you'll need the diesel.
I'll bet right now you can buy a very sweet GM with the diesel package that is just as sweet as the gasser you are looking at. You'll be able to sit back, put it in cruise control and get the job done right. Not to mention it will be ready for the next series TT after that one...
Moose.
No, as originally stated,the ~7900 is GVW rating and you definitly do not need a diesel to pull hills. In addition, the only diesel available that is not in a 3/4 T or larger is the Jeep and that doesn't have the tow capacity I'm looking for and no 3/4 ton meets my other needs.
FYI, even in my Jeep, I just sit back with the cruise set to 55 and cruise the mountains all day long.....just do it in 2nd gear at 4200 rpm. Granted diesels are great but a good gasser will also do a nice job towing.
Dick
2008 Toyota Tundra Crew Max Limited TRD
2009 Cougar 268 RLS ~8400 lbs road wt
Equal-i-zer 12,000 lb hitch, Prodigy BC.
2006 Jeep Liberty Turbo Diesel.....TV in Training
2005 Jeep GC 5.7 HEMI,(retired)
2005 Jayco Jay Feather 25Z, 4" lift (Retired)
Quote: As a senior engineer I tend to give an answer to the set-up that will be both safe and do the job correctly... But if no 3/4 ton meets your needs and you are set on the Denali - then are you only asking for justification???
The Denali will do the job, imo, up to about 7,000 lbs. towing.
Well, I think your Denali will be fine. I am towing a 2007 Jayco 31 BHS Jay Flight that is stated at 6830 dry, 9000 GVWR, 960 lb tongue weight. Trailer Weighed in at 3430 kg(close to 8000 lbs) at a weigh scale this past week with Wife and 3 kids. My TV is a 2007 Chevy Silverado 1500 CC 4X4 with the Vortec Max pkg and 4.10 gears. No problem towing whatsover, even on hills. Good luck, the Denali even has more oomph than the 6.0 in my truck. Beautiful truck the Denali is.
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