I have a Toyota 4x4 truck with 22re engine with 5 speed manual and pull a 13 Scamp
and 17 foot boat. The towing capacity is 2000 w/o stabilizer equipment, 3500 with. I hardly feel the Scamp
trailer at 1200 pounds and generally run at 60 - 65 miles an hour getting about 20 to 21 mpg. It is a dream to pull. The boat is heavier and weighs about 2000 pounds which is really starting to tax the engine on hills. It is OK on flat terrain but even going up steep hills makes usage of 2 or 3 gear frequently. If you live in mountainous area - 2000 would be a lot, IMO, for your size of truck and engine. Maybe you have more HP and it won't be a problem for you. I think my truck has 112 hp.
Also, make sure you have brakes
on the trailer. I had been pulling my boat for a few years with no problems until one day traffic was dead stopped after coming over a hill at 60 mph. I don't tailgate but really had to slam on the brakes
(wheels were smoking) and stopped within a foot of a car in front of me. The boat trailer did not come with brakes
, nor were they a option from Lowe. It is not also required for that weight
in this state.
Then there is the liability issue of overloading. Don't do it. If you get in an accident and you are over loaded, look for getting the blame and a lawsuit. You also really need to worry about swaying with a heavy load. Check out your owners manual - again, my truck is rated at 3500 lbs but only with sway prevention equipment. I would not pull that much anyway as the engine is just to small. I would also worry about an automatic shifting constantly to get up hills with that heavy of a load. I live in Mn so it is not a big issue except when crossing mountains, like where you live!
If you are using the step bumper, it is probably rated at 2000 tow/200 lb tongue capacity. You would have to upgrade to a hitch receiver, if your truck can pull the 2500 lbs. The tonque weight
should be at least 10 percent of trailer weight
or swaying can result.
I also put airshocks on my other non-four wheel drive Toyota truck, same engine. They actually worked great. Unfortunately, they leaked slowly after 2 years. I originally bought good Monroe shocks and have tried several times to find the leak. They had a 5 year warranty. I gave up and fill them up now only for heavy loads like hauling gravel, knowing in 24 hours the pressure will blead off.
You might be better to get some progressive load springs - to avoid the stiff ride when unloaded. I personally would not buy the air shocks again - though it is cool to watch the rear-end rise when you fill em up with air. Brings back thoughts of my old 1960/70 cars when it was cool to jack the rearend up.