Does a 1997 Dodge 3500 RamVan's Rear Diff. require specialfluid ?

From : dr halonfire

Q: clr wrote i just change my catalytc converter a few weeks ago and i put an oem for 5000 cc and my dakota is 3900 and now the gas millage has decreased from 18.25 mpg to 14.25 mpg. can the change have something to do with the milleage or its just a coincidence and the problem should be in other place clt. sometimes if you reduce back presure too much bigger cat the reduced back pressure can reduce part throttle responce and town mpg. bigger is not always better as you changed the tunning of your engine. -- posted using the http//www.autoforumz.com interface at authors request articles individually checked for conformance to usenet standards topic url http//www.autoforumz.com/dodge-catalytic-converter-ftopict120901.html visit topic url to contact author reg. reqd. report abuse http//www.autoforumz.com/eform.phpp=587890 .