If you mean the Mercedes Sprinter chassis, the current version is a V-6, 188 HP, or four cylinder, 166 HP.
A Class B built on the 24-foot high-top Sprinter van with dual rear wheels, will have GCWR of 15,250 pounds, GVWR of 11,030, so even loaded to max there is towing capacity for a 3900 vehicle. Usually it comes with a 5000/500 hitch, and Winnebago, for one, rates the Era to tow 5000 pounds.
Some manufacturers build on lesser vans than the 3500 dually. Ratings differ slightly, but all are enough for the Jeep.
A Class B built on the 144" WB 2500 van (19 1/2 feet long), will have a towing capacity of 5000 pounds, GVWR
A Class B built on the 170 WB 3500 SRW van (23 feet long) will be GVWR 9900 or 10,140, GCWR 15,250, with a maximum towing capacity of 7500 pounds, if you are running light enough (the empty van is just under 6000 pounds).
A Class B built on the 170 extended 3500 SRW van (24 feet long) will have the same GVWR options, same GCWR, but Daimler reduces maximum tow to 5000 pounds.
B+/Class C on the Sprinter cutaway, GCWR and GVWR are the same as for the dual rear wheel van. RV body will make the B+ about a foot longer, but it still gets the 5000 pound hitch from most manufacturers. Same numbers for the 26-foot Class A that gets built on the Sprinter bare chassis.
The alternative engine for the Sprinter van (but not cab-chassis) is a 161 HP four cylinder. It is available in any Sprinter van sold here, and has the same GCWR as the V-6 in the same van, max tow of 7500 in the 170 WB 3500 van, 5000 pounds in the others.
Current Chevy Express van comes with 4.8 V8, 285 HP, 13,000 GCWR; 6.0 V8, 342 HP, 16,000 GCWR; or 6.6 Duramax, 260 HP, 17,000 GCWR (rated slightly higher in 3500 Extended to give the empty van a 10,000 pound tow rating).
GM's tow ratings for an empty Express cargo van are at least 7000 pounds for the smaller V8 and 10,000 pounds for the larger V8 or diesel. Cargo (including RV furnishings) do cut into that, but with the larger V8 or diesel you are going to have 6000 pounds left over even with the van maxed out on weight.