The tran's fluid swap is easy. Pull the plug, let it drain, then fill it through the fill hole. For the rear end, it isn't so easy. The right way is to pull the driveshaft, pull off the rear wheels, unbolt the axle retainer nuts, pull both axles out at least 3" each side, unbolt the 3rd member and pull it out, letting grease drip and spill everywhere. Then all of the old lube has to be wiped out then both sealing surfaces have to be cleaned till grease free, then put back together with or without a gasket depending on your preference. I think $265 or more is what I would have charged you if I had to do it because you don't have a garage. I've done all of mine and it isn't as easy as it seems. What would you charge to change someone elses tranny and rear-end lube?
Take it to a Mopar Dealer and trust them before you trust a kid at a Jiffy Lube.
Rob