Someone I know just had is on line TIP denied becasue his 1 ton truck is over 3500 kg GVWR.
If you are in this situation, the restriction is cargo capacity not GVWR no matter what Banjercito claims. It is clearly laid out in both the SAT manual and the Aduana manual. Both documents are avilble on our web site (close to the top). It is smart to print out the pages form both and have them with you. It is also a good idea to have a full page photo printed out of your truck hitched to the RV with the plate numebr showing.
LINKAlso print out this screenshot of the banjercito page in Spanish where it also sasy Cargo Capacity