WOW! Did you really cut a section out of your frame and weld it back together????? Please tell me that's not what you really did!!!!!
If so, get another frame, remove the rear cross member where the pintle hitch is mounted, shorten it from the rear end and BOLT the cross member back in. If you have the access and the ability to do hot rivets like what 's originally in the frame, go for it, but otherwise, graded bolts are acceptable and safe. But one of the first things professional welders are taught is NEVER EVER WELD ON A TRUCK FRAME! When you weld a truck frame, you severely compromise the molecular structure and temper of the steel and run a HUGE risk of killing yourself or someone else when that frame breaks apart about 1/8th to 1/4th of an inch from the actual weld joint. I dunno about other states, but if the DOT in California happens to inspect it and sees the frame welded together like that, they'll red tag it, suspend your registration and likely impound it. In some rare instances where a frame rail must be welded together and there's no way around it, the proper procedure is to make the cut in a 45-degree slash angle so that the weld joint is longer and stronger, but those instances are rare as this can only be done on a non-tempered steel. All modern truck frames are tempered and should not be welded on at all, which is why everything is riveted together in the first place.
I hate to sound like a douche here, but I'd feel really bad being a professional welder/fabricator, knowing what I know, what I've seen, and not say anything and have the worst happen.
I strongly urge you to get another frame, shorten it from the rear end of the rails and bolt the rear cross member back in.
Even if you don't get caught with a welded frame and your truck taken away, even if the failure happens at low speed on an off-road trail and no one gets hurt, getting a lowboy trailer and tractor to haul your broken truck home is gonna cost a lot more than just replacing your frame and shortening it the right way.
Not to sound like a broken record here, but it's not a matter of if it fails, but when.
Please think it over!