I have a 2015 TE 4Runner and about maxing out the tow capacity with my trailer, besides shocks and upgraded oil coolers for the tranny and motor is there anything else to increase it? Im looking to hopefully get another 800lbs if possible.

"No matter what hitch, suspension, brake, cooling, or engine upgrades you make to your truck, its towing and load-carrying limits can’t change once it leaves the assembly line.”

If you ever get in an accident with a trailer heavier then than your vehicle is rated for, you will be held liable and can be sued for it.

That being said I have towed more then my 4 runner is rated for without any problem. The most important things make sure your trailer is balanced properly and have a height adjustable hitch to make sure the trailer is level.

As stated, there is no way to officially upgrade capacity, and anything you do over rated capacity is at your own risk. The rest of this is to aid in controlling a 4,999.9-lb trailer with 499.9-lb tongue weight. I'm not advocating going over weight in any way.

One huge factor is where you'll be driving. Apple Valley is mostly flat if I remember correctly, but if you're dragging this beast of a trailer around sharp curves up in the nearby mountains it could cause lots of problems.

Handling: In addition to better shocks, get either stiffer springs (ride will be horrible when unloaded) or airbags (much better solution). Stiffer tires, either in the form of E-rated sidewalls or larger rims with lower-profile tires, will help noticeably with curve control. If anyone ever makes an upgraded stabilizer (anti-sway) bar that would help. If you have a lift, get extended rear links to bring the stock stabilizer back into proper alignment.

Power: About the only proven bolt-on way to get more power out of the 5th Gen is to install a more free-flowing exhaust in the form of a URD Y-pipe and catback muffler. After the exhaust a more open CAI (TRD Pro or K&N) may also help just a tiny bit. You already mentioned coolers. Regearing to 3.91 would also help, but that's a huge expense for a small improvement (stock is 3.73). The next gearing option is 4.56, which would kill your road mileage and be a waste unless you also upsize the tires for off-roading.

Stopping: The 5th gen already has massive brakes, but most definitely you'll need an electronic ttrailer brake controller. Surge brakes (found on most rented trailers) help some, but at the weights you're talking you want active brakes on the trailer.

Thanks for the helpful advice guys, i already installed a trailer brake which helped ALOT!! i just purchesed a adjustable hitch balencer as well was looking into air ride in the back but not going to rely just on that. Hauled the trailer from texas to cali with ease and was really suprised on the comfort of it, and just pulled our 32ft rv out the sand in pismo beach which was pretty cool since the 2500hd guys were tripping out lol.

The T4R tows great but Get a WDH (weight distribution hitch) and a stabilizer bar.
The difference is night and day in handling
Weight Distribution | etrailer.com

This is the one i am using on a 3500lb trailer...... big help in rear end sag and swaying
Curt Weight Distribution System - Round Bar - 8,000 lbs GTW, 800 lbs TW Curt Weight Distribution C17051

If you can't swing that right now the sway bar alone is a big plus for control of "wag the tail" syndrome

Wieght distribution hitches are great on highways. But on anything rough or bumpy they will beat the crap out of your truck.

Thinking of picking up a Pop Up trailer..Total weight on trailer fully loaded with camping gear (water, etc) is 3,770 pounds. Can my 4runner handle this load? Should I look at a lower weight trailer? Thanks for any advice out there..

Thanks guys looking forward to see how it feels after what you guys are recommending to me, i should be around 5,100 lbs after my concession trail is done and it will be mostly flat land travel

It will haul it with ease, I haul 4 quads with luggage all the time with my 16ft cargo trailer

Thanks for the information on the hauling capacity of the 4runner. Appreciate it a lot!

Which oil cooler did you get for yours? I pulled my 3800# pop-up this weekend for the first time with a brake controller and my Gen5 felt like a slug without hills. Can't imagine going to Colorado and hitting some real hills. I feel like my wife's Odyssey pulled this same trailer better.