I bought a 99 JGC nine months ago and have had nothing but problems with it. First I had to get a gas leak fixed, then my transfer case went out and now I have an pinging under the hood. I have read a lot about swapping the 249 tc to a 242 can you do the same with the 247? Also could the pinging under the hood be a lifter? It doesn't do it all the time it usually does it after the jeep has warmed up. The longer I drive it the worse the ping. We are trying to figure out if it is a rod or lifter. How would one go about finding out?