I have a 84 d100 with a slant 6, 2wd, and about a month ago we put a new catalatic converter on it, the old one clapsed. Lately we have just started driving it on the road, and have noticed a deep noise coming from the truck when you have it in 3rd or 4th gear, but only when acceleration. The catalatic converter can be the only thing that I can think of If you have any suggestuions please help
thanks