GM's Chevrolets and GMC - Montana Owners Club

ken · 06-09-2005, 02:19 AM

How about some input into the Diesel that GM puts in their trucks. Are you satisifed with the towing and fuel millage. And Have you had any problems with the trucks. I sdee a lot of you have them. We drive a Ford F350 right now but have been looking at the GM's. Is the 2500 enough truck to pull a 13,000 pound Montana? Sure need some help here.
Ken And Velda Taylor
Dahlgren VA
2005 3475 Montana
2000 Ford F350 Diesel

RMccord · 06-09-2005, 03:04 AM

I have a 25ooHD GMC SIerra LB Ext Cab Duramx/Allison.
I get very good mileage and have plenty of power. I averaged 13.1 mpg towing my 335RLBS from Santa Paula to Buelton and back. I averaged 11.7 doing same from Santa Paula to Bakersfield and back and that was witht the Grapevine in between. I tow in tow haul mod always and at about 58-60 mph.
It downshifts once going up the grade and traffic permitting never looses a mph.
I only have about 4500 miles on it so far. My self if I did anything over I would get the Crew Cab Long Bed instead of the Extended Cab(four door) with Long Bed. The Long bed has a larger fuel tank.
Also I use Stanadyne Performance Formula in every tank of fuel.
I think the Allison trans is ourtstanding. Also if you wait just a bit they are adding another gear to the Allison and it will be a 6 spped with some different levels of tow haul mod. I think that will make the rig even better.
As for the HD handling your trailer I would feel it would. It has a GCVR of 22000 with the Duramax and 3.73 axle ratio. The 2500hd is a 1 ton configuration according to my dealer and I retired from GMAC.
I would certainly give them a hard look. I am very pleased with mine. Also they are the quitest of the 3 GM, Ford and Dodge.

Bill and Ann · 06-09-2005, 03:13 AM

The GMC/Duramax/Allsion is a great combo. I am getting about 14 mpg when towing and 24 mpg without. I also use towmode when towing. The only thing I would change if ordering a new truck would be putting 265 tires on instead of the stock 245's. Gives you the extra weight capabilities.
I had to change the injectors last winter. Around 50000 miles on the truck. Warranty of course.
My brother recently went from a Dodge 2500 to a new GMC 2500 with the Duramax.

Bill Hill · 06-09-2005, 04:21 AM

I love our 2500HD D/A. The early '04s were rated at 520 ft.lb. torque, but the '05s are rated at 590 I believe, lots of torque. The Allison with the tow/haul mode is a great transmission, almost like having a manual, but better. Add a good exhaust brake and you've got a terrific combo. Ditto on everything said about weights. I'm a firm believer in the 80% rule, don't tow more than 80% of your capacity. The 5th wheel tow capacity of our truck is 15,000 lb, our trailer gross is 12,460, and I think I'm closer to 12,000 most of the time. I like having a little margin.

OntMont · 06-09-2005, 05:18 AM

We have a 2001 2500HD with 120,000 km (about 80,000 miles). We have been towing with it since it was new with a 3255RL and more recently a 3670RL. The truck has performed flawlessly as far as the Duramax engine and Allison transmission are concenned. The only problem we have had was a rear universal joint failed at about 100,000 km. and a fuel filter that plugged up, probably because of bad fuel somewhere.

Pulling is no problem, weight distribution might be. To be strictly legal, you can not exceed any of the weight ratings. We are fine on everything but the GVWR. We need to get a bit of weight off the pin and onto the trailer wheels. The only accurate way to know this is by weighing the rig, loaded for camping. If you know your loaded pin weight, you can look at the published Payload ratings and try to figure out if you would meet them. Note that the payload has to include other passengers, your hitch and whatever else you carry in the truck. I have been "brochure browsing" recently and was surprised to find that although the SRW F350 Ford trucks have a higher GVWR than the equivalent from GM, the Ford Payloads are actually lower, which makes me think that the Ford trucks must me heavier.

The 6 speed Alison that is being introduced for '06 is supposed to improve fuel economy.

Anyway, they are all good reliable trucks, just do your homework on weights and make sure you get what you need. Don't listen to salesmen (Truck or RV), you are the one who is responsible for your rig.

Hope this helps.

DHenry · 06-09-2005, 06:34 AM

As with all of the above, we are very happy with our '02 Chevy Duramax. We are getting 11.5 towing and have had no problems with the truck at all. Good luck on your choice.

Karl · 06-09-2005, 07:35 AM

We have a Montana 3295 and pull it with a GMC 2500, 2003 Duramax/Allison. Although we did have the injectors replaced under warranty this winter (there is a 100,000 mile warranty on those parts), we have been very satisfied. The ride is great, the mileage ranges from 10 to 12 mpg pulling and 20+ empty. The injector problem was discovered fairly early, and Izuzu has addressed the issue since that time, so the newer Duramax's have redesigned injectors.

We did opt to purchase a Hypertech III programmer, and I have programmed that for the mid level of performance enhancement. It seems to give a bit better mileage with that, and the uphill pulling power is just tremendous, even on 7% plus grades.

Our GMC is a crew cab (full rear seat and doors) with a 6.5 ft box. While I had a slider hitch installed, the extended hitchpin of the Monty and the "cutback" of the front of the coach has made it unnecessary for me to use the slider. Of course when backing tightly, I do keep a close watch on the back of the cab/front of the 5er.

Montana_2753 · 06-09-2005, 12:01 PM

I used a friend's 2005 Chevy Duramax dually longbed, crew cab to tow my Big Sky to AZ from North San Diego County, using I-10 East. What a dream towing! I had to check mirrors often (which you should do, anyway) to make sure the "Big Guy Big Sky" was still there. The long, steady grade from Indio to Blythe was no problem and once I set the tow-haul and cruise to 60mph, it was clear sailing, with more than enough power to pass 18 wheelers. Not sure about the mileage, but left with a full tank and arrived with more than 1/4 tank, a distance of around 270 miles. I am definitely convinced this is the setup I'm buying (from a kinda die-hard Ford man).

Bruce

rames14 · 06-09-2005, 01:14 PM

We went from a TT with a Tahoe to 3400RL and Duramax/Allison 2500HD, Short Bed, Crew Cab, 4x4. Like previously mentioned, have to check to see the big guys still back there. I used to have to grip the wheel, and still had issues when passing/being passed. Silverado is like a Tahoe with a bed on it. I have had two issues. First, bad valve on the turbo and currently had to replace a fuel filter. I anticipate we'll have this unit for the next four or five years. I was getting about 13 towing/22 on the road until I ran into the fuel filter issue. I also need to check air filters now. We have about 19k miles. Even if I wasn't a GM guy, the Allison would be the major difference between the other brands. All will do the job, after that its personal preference/bias.

padredw · 06-09-2005, 03:27 PM

As you see below, we have the Chevrolet Duramax with Allison transmission. It makes for a great towing vehicle. I am responding because there have been a couple of comments about the fuel filter. I'll share an "interesing" experience about that.

A month of so ago, we were on the first leg of a trip to Austin, Texas with our Montana. We spent a couple of nights at Tyler State Park to visit with friends in that city. On a Friday night we visited with friends, parking the pickup in the driveway. When we went to leave, the pickup would NOT start: battery was strong, turned the engine without fail, but not a 'spark of life' from the engine. We finally called AAA, but on a Friday night they had only one operator and it was a couple of hours before he could come. After that time and he had not arrived, I just tried once more and the engine started perfectly normally. The next day, not a hesitation in starting and we pulled the Montana on to Austin. On Monday, I was to drive the pickup to the University when, for the second time, it would not start. But by now my wife had "read the book" and noted the manual fuel pump. I utilized that instrument and got an immediate start.

My dealer's location was on our way home, so we called before leaving Austin and made an appointment. After their examination, the service manager asked, "When did you last change your fuel filter?" I told him I had no idea, but was not aware that it had ever been changed (about 45000 miles on my truck). He told me, "Your fuel filter should have been changed every 15000 miles."

Of course, the fuel filter was changed and the pickup has never again exhibited that type of behavior.

The "funny" thing is that, driving and towing, once the engine started it ran perfectly normally. Not a hesitation, no greater fuel usage. Strange but true.

mobrownies · 06-09-2005, 07:06 PM

We have had ours for almost two years and no complaints. We have only pulled for about 2,000 miles and love the way it pulls. However, as OntMont mentioned, I am concerned about weight distribution. Most trailer manufacturers and dealers are mis-leading about actual pin weights. Most are a lot heavier than the book says, even before you load your stuff. I think the truck is rated at 9200lbs and we were over that by 50lbs before we loaded. So we are going to have to take care when loading to move the center of gravity back further. I hope I don't have to add counter-weights just to make it work.

Bigger tires might improve the tire life, and air bags might make it ride level, but the axle is the limiting factor.

Having said all that, you sure see a lot of people towing rigs bigger than mine on 3/4 and 3/4HD pick-ups. I'm either too causious or there are a lot of overloaded trucks out there.

Montana_2753 · 06-09-2005, 07:26 PM

IMHO quite a few people NEVER weigh their rigs (osterich in the sand

) and are probably overweight. Look at sreigle's posts and you can see how "easy" it can be to be overweight without realizing it. I'm certainly no expert, but from what I have read and heard, being overweight (pin, gross, axle, etc.) and disproportionate front/back & left/right loading are major causes of problems.

Bruce

sreigle · 06-10-2005, 04:45 AM

Bruce, I agree. I think you hit on something that is very easy to overlook because it's just not easy to get the numbers. That's the disproportionate loading from left to right. It's important to know the weight on EACH axle separately, which I neglected to do this last weighing. If the axles are rated for 6,000 lbs each, then if we find the combined weight on the axles is 11,500, we assume we're ok on GAWR. But what if the weight on one of those axles is 6,200 and the other is 5,300? Then we're over on one of the axles and may cause a problem.

Likewise, weight on one side or the other. We could be ok on weight on the axles but over the tire's rating on one side or the other. The scales I've used do not lend themselves to weighing each side separately or even just one side at a time. Most seem to have the scales up on a ramp so you can't put just one side on the scale. I guess I need to watch for a scale that would allow this kind of weighing.

OntMont · 06-10-2005, 06:22 AM

I remember hearing of an organization that has the equipment to weigh each wheel of an RV/TV saparately. Does anyone know of them? I wonder if we could get them out to one of our rallies?

tweir · 06-10-2005, 07:04 AM

Just got back from San Marcos to Vegas round trip---a bit over 300 miles each way towing a 3685FL w/'05 D/A Dually. Mileage averaged 10 mpg with a 15-20 mph headwind going over and 13 on the return leg. Averaged 62 mph in tow/haul going over & 65 mph on the return leg. That 16 mile 6%+ grade from Baker, CA to Searchlight caused the truck to downshift into 4th. about 2 miles from the summit---pretty steep grade at that point. That trailer is heavy & the wind did not help either. The Cajon Pass was a breeze. The key to the LLY engine is running it at or just below 2000 rpm---that seems to be the "sweet spot" for mileage & torgue.

Montana_2785 · 06-10-2005, 08:55 AM

Quote:

quote:Originally posted by OntMont

I remember hearing of an organization that has the equipment to weigh each wheel of an RV/TV saparately. Does anyone know of them? I wonder if we could get them out to one of our rallies?

http://www.rvsafety.org/schedule.cfm

Bill and Ann · 06-11-2005, 12:52 AM

John (OntMont) How did you make out at the Flying J scales? Any surprises?

OntMont · 06-11-2005, 04:32 AM

Quote:

quote:Originally posted by Bill and Ann

John (OntMont) How did you make out at the Flying J scales? Any surprises?

No surprises, we were a little over our GVWR, but OK on all axles and Combination. We are trying to tweak our loading to see if we can get the GRVW load down.

The more I think of this, it does not seem logical that the truck's GVWR should apply to pulling a trailer, with its own brakes and suspension, the same as it does for a static load like say, a load of sand; that the truck has to be able to handle with its own brakes and suspension. But then, who said GRVWs were logical anyway?

One nice thing, they did not even charge me for the re-weigh with the front legs down. Thaks for that tip. Too bad we don't have a scale closer to home, I don't too often get the chance for a good weigh.

sreigle · 06-11-2005, 08:18 AM

John, the GVWR of the truck applies only to the truck weight and everything loaded in the truck, including the pinweight. The truck's GCWR relates to weight of truck and trailer together. I hope I didn't misunderstand your comment. We're over on the truck's GVWR, also, but not over on GCWR and tow rating.

Montana Sky · 06-11-2005, 11:13 AM

Well I cant add anything that the pervious post have already covered. I only wanted to mention that this is my second Duramax and know there will be a third some day. Towing the 3400RL I average 14mpg and empty I run right around 21-23mpg. Put 510miles on 21.4gals today giving me a 21.3mpg on one tank. Just love the way this truck works. =)

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