Tow Vehicle

Myrjer · 06-30-2003, 07:51 PM

Question for anyone familiar with tow vehicle requirements. I just bought a 1977 Excella. I believe the weight is 8000 lbs. I also just bought a 1996 GMC 3/4 Ton with the 6.5 Turbo Diesel. I 'm trying to verify the gear ratio of this truck . I think it is 3:42. If so , is that low enough to pull 8000 lb . trailer? Any harm if not other than poorer fuel mileage?

59toaster · 06-30-2003, 08:07 PM

Well Deisels do run a higher gear (numericly lower) due to lower RPM's they run at. 3.42 is kind of in the grey area. 3.73 would be better. That's a lot of weight.
What happens is the strain is transfered to the transmission. I would put as big of AUX transmission cooler as you can find on there if it doesn't have one already. I like "Stack Plate" coolers. They have a larger cooling capacity for their overall size then the tradisions tube and fin coolers.

To verify the gear ration look in the glove box and there is a RPO build sheet sticker with a bunch of 3 digit codes. That tells EVERYTHING about the truck.
Google Search of RPO codes.
On page 2 is a PDF on a web sit listed as Polariswebdesign. She's a internet buddy of mine and I have found that one helpfull but may not cover as new as your vehicle. I think this will work as a direct link. http://polariswebdesign.com/GMRPOCodes.pdf

thenewkid64 · 06-30-2003, 08:13 PM

Myrjer,

Welcome to the forum!

In 77 the Excella was either an option Package, not the model name as in later years. Or someone has modified the trailer to "Update" it's look.

Your trailer is more than likely a 31 foot model. The dry weight is 5800 lbs, and if memory serves max weight is either 6800 or 7100 lbs. with a hitch weight between 620 and 715 lbs.

A 3/4 ton truck with proper hitch hardware should tow this trailer fine, but the only way to certify the rear end ratio is to llok at the build sticker either under the hood, or in the engine compartment. It will be a bunch of numbers and letters and you will need a decoder to figure out what ones signify the rear end ratio. Your local GM dealer should be able to help you out.

You need to get a weight distributing hitch and I would reccomend some type of sway control for both your safety and the safety of others.

RoadKingMoe · 06-30-2003, 10:02 PM

If you can't find the build sheet, get some bright chalk and put a mark on a rear tire at the ground. Then put a horizontal chalk mark on the side of the driveshaft on the opposite side of the truck. While laying on the ground on the side with the tire mark, have someone slowly drive the truck forward or backward one tire revolution, while you count the driveshaft rotations. The first time you see the mark will be .5, the next 1.5, and so on. With a limited number of available axle ratios, you can usually chose the right one doing this.

davidz71 · 06-30-2003, 10:11 PM

If your '77 Excella 500 is a 31' rear bath model, the Gross Vehicle Weight Rating (max. the vehicle can weight when towing) is 8500 lbs., factory wt. without options is 5880 lbs., allowable additional total wt. including personal cargo is 2620 lbs., Gross Axle Weight Rating (max. load that can be carried on the axle system when the trailer is being towed) is 8000 lbs. and factory tongue wt. without options is 697 lbs. Maximum tongue load should not exceed 1000 lbs. and the GAWR or 8000 lbs. should not be exceeded.

The liquid in a full 10 gal. water tank weighs 50 lbs., fresh water tank liquid weighs 373 lbs., 7.5 gallon propane tanks weigh 30 lbs. each with liquid but you probably have the 10 gallon tanks which weigh 40-45 lbs. each.

If you have an owners manual, it would explain step by step all the weights you should calculate for a trip. Then you should have your trailer weighed to see what the real figures are.

If I have confused you, send me a private message and I will try to help you out.

Myrjer · 06-30-2003, 10:12 PM

Thanks everyone. Your input gives me much to work with. I have purchased and equalizer hitch and already have a sway bar which I intend to use for sure. Will get busy tomorrow determining my axle ratio. Best wishes .
Jerry

j54mark · 07-01-2003, 12:27 AM

Water is eight pounds to the gallon, not five.

I doubt your 3/4 ton Chevy has a 3.42. I would be surprised to learn it was an option with the 6.5 turbo diesel. But, as noted above, there are ways to determine it.

More likely it is a 3.72, or with luck a 4.10. I have a '94 6.5 turbo diesel with a 3.72, and here in the Ozarks it is adequate for my '85 Sovereign 25' at towing weight of about 5500 lbs. We are just back from a week in the Rockies where towing performance was NOT acceptable. It might have been ok with a 4.10, I don't know.

Mark

Myrjer · 07-02-2003, 01:45 PM

Thanks Mark. I'm just assuming it is 3:42 based on the fuel mileage I'm getting. ( 21MPH ) I just got back in town so haven't had time to check it yet since these replies were posted. Hope to check it out this weekend.

davidz71 · 07-02-2003, 11:29 PM

j54mark,
I seem to remember that you are correct on the wt. of a gallon of water being 8 lbs.. My owners manual shows varible weight of the water heater to be 50 lbs. and since the Excella has a 10 gallon tank I just figured 5 lbs. per gallon. Could an empty 10 gallon water heater weigh 50 lbs. and this is why the weight is shown as such? I've also noticed that my manual mentions a 6 gallon tank as well as a 10 gallon tank. How do I determine which I have in the Excella package short of filling it up and draining her out?

thenewkid64 · 07-02-2003, 11:45 PM

Craig,

Look inside the door and see if you can read the model number off the plate from atwood.

If it is g6XX it is a 6 gallon, if it is a g10XX it is a ten gallon. Normally the 10 gallon models were installed in the rear bath coaches that had a small bathtub. If you have a shower it is unlikely that the heater is a 10 gallon model.

davidz71 · 07-03-2003, 08:55 PM

Thanks Brett,
I looked a little closer and on the side was a faded sticker that said 6.2 gallon. I guess I should have looked a little closer but i'm still getting to know the beast and loving every minute of it.