I've seen otherwise, but I'll tell you my experience. I had a pintle hitch on the crossmember, and only used it to pull myself out of a couple of spots where I got high centered. Nothing major, just need a little help.
This ended up deflecting the crossmember.
So therefore I'd say it's not the best place to mount up to for pulling. But like I said, I've seen folks do otherwise... I'm just not so sure how smart that is to do.
That's weigh more (couldn't help myself from punning) than you'll likely want to try. For loads that heavy, the manual specifically calls for a frame-mounted hitch. Unless it's stripped down, a 40 is going to weigh 3500 or more. wikipedia says 3,427 lbs for a hardtop FJ40. You'd have to also count the dolly weight, which would definitely put you in the red zone.
I've done one ton loads in town and its seems pretty heavy. I'd hate to take a long drive with it at highway speeds.
EDIT: Here the specs from the owner's manual for easy reference, since I wrote them up for a similar conversation recently.
My 97 is placarded on the drivers door for 6470 pounds GVWR. That is with the stock tires, which are relatively low capacity tires with 32 PSI max. On page 198, the 97 owner's manual indicates that you can inflate the stock tires to 35 psi when towing. But most of us aren't running stock tires, so you will need to check specs on whatever you're running. In most cases, 33" and up truck tires will have plenty of capacity.
The placarded GAWR -- the max capacity on one axle -- is 3305 on the front and 3970 for the rear. That comes to 7275 pounds. The GAWR include tongue weight of trailer only, NOT total weight of trailer.
Now go to page 134. "With towing package" seems to indicate that the standard frame mounted dealer-installed hitch. Without the "towing package" shows a 3500 towing capacity, while with it you're good for up to 5000 pounds. Total of vehicle and trailer without towing package is 10025 max and with it is 11525 pounds max.