Hey all,
I know this is for Silverado but I really need help. I have a 1999 Gmc Suburban 4x4 5.7L that can't my boat. I know a 3/4 ton has to pull my boat because it so big. How can I make my suburban haul my boat without changing the rear axle. I put a whole bunch of Fashion stuff on this truck already now I need it to tow my boat. I am tired of piling into my Ford F350 crew cab just to go to the lake. I have a family of 6 try hauling everybody and stuff for the lake and the boat sometimes I end bringing my suburban along with the F350 because it is so crowded which is crazy because I have a triton V10 in my F350 which can be a gas hog along with the gas hog Suburban. I traded my 1999 Ford Excursion 2wd for this suburban and the excursion was able to pull it like nothing. Please help. Plus can I take the barn doors off my 1997 wrecked suburban and put them on my 1999 Gmc Suburban because I am tired of replacing the hydraulics to hold the window up.
Trav

 

Well ... I have no idea how big your boat is ... but I don't know what you mean by "can't" pull your boat. Do you mean it strains excessively? Because I highly doubt the 5.7L engine "can't" move the boat. Unless your boat is the size of a house, I imagine a 5.7L engine will be able to pull a boat just fine.

However, gearing is key when towing. Torque is your friend, and tall gears, like the 2.73 gears in my truck, aren't the best for towing.

Changing out the gears in the rear end isn't a huge deal ... just need to get a kit from summit

 

Gearing will get you moving, but Is the Burb, sprung for the weight of the boat?

 

The rear end sags to much. It goes pretty far down that I don't truck putting it on the road and I am use to carrying big loads but one good sized pot hole in the road and the truck will have the bumper grinding the ground. The gearing I am sure can handle it I had the rear end rebuilt for towing. I was looking something up maybe could I put an air suspension on it then I should be fine. Is this possible on a Suburban? Again my boat is about a 38 footer maybe longer not shorter though. I can bring my family and my two brother's family in it and we have quit a bit of room. My suburban can pull my fishing boat it is only an alumium 14 ft made for 6 people but I am talking about the 38 footer. I am not sure of this but a friend told me I could get a 3/4 ton diesel suburban brand new which might be a better choice for me but I can't find any options about that. If I could get an air suspension I would be good considering the fact that everything is very cabable my last suburban the 97 I had before I wrecked it had a 3/4 ton rear end put in it and it was able to pull the boat it had the same engine but I can't take that rear end out of it because it has the ABS locked up and I can't get it unlocked.
Trav

 

I'm thinking the total weight of truck,gear, fuel, boat and trailer, and family of six is exceeding the max gross vehicle weight of your Suburban. It could be pushing the limits of your one ton. You can make all the mods you want to the drive train and suspension, but you still have to worry about the brakes. And your local traffic authority can only go by the max weight allowed on your trucks door post despite all your modifications. If you were to get inspected or in an accident with that load on your Suburban the fine could be very steep.

 

Well I know for a fact it isn't pushing my 1 ton's limit. It doesn't even budge my F350. What I don't get is I pulled the boat and family of 6 and lots more fuel with my daughter's F150 with a 3/4 ton rear end and it did fine only budged about 5 inches. The boat is really light yet to heavy for a 1/2 ton. If I had a way to actually upgrade my Suburban's rear end I would be good. I just don't want to reaplace the whole rear end it was a pain doing it in my last suburban. I am about to go trade this thing in for a 2012 Ford Expedition EL King Ranch 4x4 if it doesn't want to pull my boat. Don't get me wrong I like this suburban but it is anoying not being able to pull my families boat. I know the Expedition EL will pull it because my brother has one that can pull this.

 

Just because a vehicle CAN move a load, doesn't mean it should. The only way to know for sure is to weigh it. This would be good information to have anyway if you do buy a different tow vehicle. Check this weight against the door post info, don't trust the salesman on this. For the commission on that type of truck he may tell you it can fly!

When you say change the rear end are you talking about the suspension or the gear ratio in the differential? I assume your using a good, frame mounted, weight distributing hitch and not just a trailer ball on the bumper.

A 4X4 often has a lower tow rating than a 2 wheel drive because of the weight of the transfer case and front differential. But the 4 wheel drive can be needed when removing the boat on wet boat ramps.

 

Well whatever you are going to say it doesn't matter now. I sold both of the suburbans and got a 2002 Ford Excursion 4x4 6.8L Triton V10 I love having an Excursion again so sorry to yall Chevy guys. Plus my son traded in his 1981 Chevy K10 for a 2012 Ford F250 4x4 super cab.
Trav

 

lol well I was about to suggest you add in a leaf spring or two to keep the ear end up, but it doesn't matter now.

The "rear end" doesn't to sh*t to holding up the rear end. It's the springs that actually "hold" up the body from scraping on the ground. The axle strength is the thickness of the axles inside of the axle housing. Stronger axles will make for a safer haul, but as far as keeping the rear end up, that's all up to the leaf springs.

 

Well thanks for the advice anyways as my Excursion might need some help so if I add a leaf or two I will be able to haul a bit better. Plus I am adding an air suspension to the truck. I am loving having my Excursion back.
Trav