Check in your glove box there should be a sticker in there with the specs. Also on the rear end diff cover there may be a metal tag on the cover bolts . And lube specs i went with Mopar 75w-140 synthetic and there anti- slip aditive If you don,t have a manual you can call the dealership parts department and they should beable to look it up. It cost me $123. 00 for the oil,aditive and silicon there for the rear only. When i do it again i might get oil from someone else like Amsoil,Redline ext.