Trans and Axle oil leaking and problems

Take it back to the shop and have them do it over. They should stand behind their work.

I had the same issue with my Ford E350 van that had a leak around the differential cover. Pulled it off and one could see where when it was installed there wasn't enough sealant on the mating surfaces or, it was installed improperly.

I used a silicone made by, I think, Permatex and it was specifically for differential applications in that it was resistant to differential lube. Other silicones will fail after a period of time. I think the silicone you got from Dodge was probably the correct stuff so the problem most likely stemmed from the installation of the cover. The directions I received said to make sure the mating surfaces were absolutely clean and free of any oil or silicone residue(or something like that) as well as other contaminants. I scraped, washed and used lacquer thinner on the mating surfaces before putting the cover back on. Next you have to torque the bolts to a certain value( can't remember what value, something like so many inch pounds) and then let everything sit for a day or so. The next day, you tighten all the bolts to something like 35 ft/lbs and then you're done. I did this a year ago and so far so good.