727 issues and questions

OK Hi, I'm new to this forum I spend most of my on old Jeep forums.

I've got a 71 Dodge Winnebago with 318 Magnum 727 NP207 transfer case, Yes it's a 4X4 camper with a lift kit and 33" tires. It's great for camping on the beach. But now when it shifts between gears say 2nd and 3rd the engine will race like it's not in gear, sometimes I let off the gas to lower the rpm and sometimes I slide the shifter to N then back to D till I can feel it engage and it's fine while in third. I'm guessing the clutch bands going bad. The fluid level is OK. Also today on my way home I was stopped to pull into my street and when I got on the gas to pull up my road it was slipping but when I let off the gas it work fine again. My question is could it be the shifter linkage? Or does it sound like the clutches.

winnebago063.jpg

Matt