I do not know the clearance of for a 2553, but I do know that an Over-under kit is available to raise up the trailer, available directly from Dexter Axle. My dad did this to his Car Trailer a couple years ago and it really made a difference. It has a beaver tail, so the back slopes down. He wanted to take it hunting with him, to haul ATV's, a generator, firewood, etc. Taking a trailer with a clearance of 4" under the beaver tail was not a good idea, so the kit raised it another 4-6". The only issue now is that we can't put it in the garage without putting on smaller wheels with small tires (for a pop-up). It is a very simple kit to install, it just requires removing the leaf springs to remove the axles so they can be reinstalled on the underside of the leaf springs. I am assuming this trailer has the leaf spring suspension and not rubber ride.
For tips on how to flip axles, check out this link from an owner of a 1999 T-2553 who flipped his axles because he has a similar problem with his driveway also.
Good luck with your possible purchase! Sunline is the best of the best! Just as the 1991 Sunline brochure said, "Life is even better in a Sunline"
2007 T-286SR Cherry/Granola, #6236, original owner, current mileage: 9467.8 (as of 5/26/19)
1997 T-2653 Blue Denim, #5471
1979 12 1/2' MC, Beige & Avocado, #4639
Past Sunlines: '97 T-2653 #5089, '94 T-2251, '86 T-1550, '94 T-2363, '98 T-270SR