I'm upgrading from my 1995 Dodge Ram 4X4,1500 club cab(5.9-L)to 2008 Silverado 2500HD,4X4,crew cab,6.0-L gas engine. I mainly use the truck for recreation purposes and average 7,000 miles a year. I trailer my 220 Chaparral(6,000lbs.w/trailer)about 5 times a year. My Dodge would tow the boat fine until I would get into the Ozark hills in Missouri,then I was disappointed in the performance. I can't afford the 6.6-L diesel so I have to settle for the gas engine. Should I be concern if the truck has 3.73 or 4.10 gear in it.

3.73 is plenty for 6k. The new 6 speed auto makes a big difference.

You should be fine with the 3.73s.

You can afford the diesel. You can get a 2007 Classic Crew Cab 4wd for around 30K or less in the midwest. We paid 31K for ours with 12K miles. Out here gas prices are catching diesel prices which further builds the case for diesel. The classic and the new style 2500HD use the same chassis. Only the 1500 got the GMT900 chassis.

I'd go with the 4.10's. I have them and they're a good match with a 6.0L and hills. You will lose only 1 mpg.

You think they're still necessary with the new 6-speed auto and VVT engine?

A worthwhile read:

http://trailerboats.com/output.cfm?id=1255645&sectionid=318

Necessary, no. Better at pulling a grade, yes.

I'm hearing that the GMT900 will be going to the 2500HD in 09 or 2010 and a new platform a few years after that. Magazines could be wrong, especially if they are simply reading and retyping the press releases which happens on occasion.

One of the reasons I went to the Classic is because I don't have the soot scrubber which is one more thing to go wrong.

Either one is going to be capable and the P.O. can get an 07 diesel for the same price as an 08 gasser.

Thanks for the read D-Rod. I have several trucks to chose from and only one of them have the 4.10 gears. It looks like I will be fine with either setup.

I thought the 3.73 was the only available ratio for the new 6-speed ???

I know that we opted for the 4.10 in our Suburban, but that's the older 4 speed setup

Pacesetter, as with all gas engines, to get the most out of it while towing you should go with the "deeper" gear.
If she's gonna be used to tow stuff and not as a daily commuter the 4.10 makes more sense to me. You'll find, again while towing, that the fuel mileage difference between the two is negligible.
Occasional towing with lots of "regular" miles....go the other way and get the 3.73.

Conventional thinking went out the door with the new 6-speeds.

Don't buy the 4.10's until you have driven the 3.73's. Power is not going to be an issue.

For the record, pushing O/D off (5th gear) has the same net effect on the highway as what 4.10's would have had with the old 4-speed tranny. And with 3.73's, one still has better gearing to accelerate from the stop light or throughout any of the RPM range. On top of those advantages, the 08's use a VVT engine which provides considerably more grunt than the 6.0's of the past.

Power is not going to be the problem.

IMO, if you're in the position to buy new and get exactly what you want, and you're gonna use the truck for mainly towing and not commuting, why give up anything with the gearing....

I don't think you're giving up anything. Infact, I think you might be gaining some. With 4.10's, you going to be be doing a TON of shifting.

Not so. Either gear sets will be fine from a stop. Pulling a grade may find less downshifting with the 4.10's vs the 3.73's, especially if you keep it out of trailering mode. Keeping it out of trailering may result in higher fuel mileage. I think the weight of the boat puts it right on the border of whether trailering mode should be used or not. I DO NOT use trailering mode towing my 226 Cobalt (probably close to 6k lbs). There is enough power and gearing to not lug the engine.

Pacesetter, do you know the tire size with either gear ratio options?

Trailer mode increases the fluid pressure in the transmission, thus helping handling the stress/heat. At least that's what I was told. I use TowHaul on the highway with our 04's Tahoe Z71. Keeps the torque convertor locked up. In town, I flip it off.

I don't think 4.10's are going to prevent a downshift on a long grade in the Ozarks. Those are some fairly long steep mountains/hills.

I have a 2007 NBS 6.0 with VVT 4 speed auto & 3:37 gears and pull a 5200lbs.(dry) Stingray 240CR. The 6.0 has plenty of power once you get past the 4 sec. torque Management delay.
Get 10 mpg pulling interstate 65-70 mph.

3.42 or 3.73?

I get 12 mpg pulling my Cobalt 65-70, with the old 6.0L 4-speed 4L60e and 4.10's (go figure), which was 50% better than either one of my Ram 1500's 5.2 or 5.9 gasser returned (8 with those).

And again, I do not use tow/haul mode, as it lets the engine rev too much and the trans downshifts too quickly. Tow/haul mode would be better suited for heavier loads. I leave it in overdrive, and put the cruise on if traffic allows. I plan ahead for the hills or traffic. The trans temp never gets above 200°F, and I service the trans once a year in the spring.

What works for me may not work for someone else.

You do have a bigger engine and better gear than our Tahoe has. Our Tahoe won't pull the our boat 65-70 with the cruise on unless it's 3rd. It's too much for O/D to handle at 2,000 rpms. I've noticed T/H holds gears longer before forcing an upshift. Example, If i'm motoring along around 68 and hit a small incline, and my speed slowly tapers off to 62/63 while i'm pushing the throttle to the brink of shifting, with TH on, it will keep it locked in O/D and allow me to slowly deaccelerate. With T/H off, it gets upset and start unlocking the T/C or downshifting into 3rd unless I back off the throttle (which I don't want to do). However, if I quickly react with the throttle, it will immediate force a downshift. The other nice thing is that when a downshift is needed, T/H does a good job of holding 3rd under lighter throttle until I get to my desired speed. So, I suppose T/H is a two way street. And something to remember is our Lowe, although lightweight, it like towing a freaking kite with air resistance. We get 9-10mpg towing. If I drive 55, I can get 11mpg.

At any rate, this is obviously not going to be a problem with a 6.0L engine. And given that your 6.0L with 4.10's and 4 speed auto does a very nice job with 6500lbs or so, then it stands to reason the newer, more powerful 6.0 with 6-speed should be exceptional with 3.73's.

But, you know, when in doubt, go with the 4.10s.

D

Well I purchased the Silverado 2500,4X4,crew cab,vortec 6.0L,w/6speed trans,4.10 ratio Monday. It seems like it has plenty of pep. I was surprised to see that at 70 MPH the tach reads 1800-2000 RPM's with that gear ratio. cny boater, the tire size is LT265/75R17.I will be driving it this week to get some engine breakin. This weekend I hope to trailer the boat to a local lake. There are some pretty steep grades (nothing like the Ozarks) I will see if I need to use tow mode or not! Thanks for the great information that I couldn't find using Google!

Congrats!!!!

Hey. Read your owners manual. There is a break in tow period too. No full-throttle starts and don't exceed 55mph for X number of miles. It's probably worth considering to follow. And...I don't think you're going to notice the boat is back there!

I probally need to slow down and read the manual. It's been a busy time locating and puchasing this truck. I still need to get the new trailer wiring plug that will adapt to the new truck. I can't wait to get the boat to the lake and enjoy some time on the water!!!!!

Just skip to the towing section. It'll take about 5 minutes to read.

Congrats Pacesetter. New truck smell......I'm envious!!!

3.42 or 3.73?
Oops! Typo 3:73

SKP05 I have 4.10 axle ratio.