usmc m54 Posted March 1, 2006 Share Posted March 1, 2006 I stumbed across a 1964 5 ton military truck for sale, with the 673 in it. I am seriously considering the purchase of it. My question is, were they problematic?? I heard stories from certain individuals the pumps were prone to failure. I have some experience driving the 673's and loved it, having no problems. On the otherhand, I own a 1965 Multifuel 5 ton which of course has had its share of bad publicity, but I've never had a problem with it so far for 30,000 miles, which is alot for a military vehicle. Just wanted to hear the opinions from the pros here. Quote Link to comment Share on other sites More sharing options...
rebelend52 Posted March 1, 2006 Share Posted March 1, 2006 I stumbed across a 1964 5 ton military truck for sale, with the 673 in it. I am seriously considering the purchase of it. My question is, were they problematic?? I heard stories from certain individuals the pumps were prone to failure. I have some experience driving the 673's and loved it, having no problems. On the otherhand, I own a 1965 Multifuel 5 ton which of course has had its share of bad publicity, but I've never had a problem with it so far for 30,000 miles, which is alot for a military vehicle. Just wanted to hear the opinions from the pros here.I have two B models with 673's. They are great engines and really reliable. One of mine sat for 7 years and after new batteries cranked right up with just a little hand priming. As for beign problematic...I know a guy that has used his b model (with a 673) for light duty construction work for the past 20 years and all he had to do was replace a battery cable. The engines are reliable and easy to work on..I say go for it. Quote Link to comment Share on other sites More sharing options...
Dick815th Posted March 11, 2006 Share Posted March 11, 2006 MV,36 years ago I had just wrapped up a year and a half tour in an Engineer outfit across the pond. My primary MOS was Engineer equipment repair but I ended up helping maintain a fleet of M51A1 and M51A2 5 ton dump trucks, M123A1C 10 ton tractors and a smattering of M35A1 2 1/2 ton trucks, about 35 trucks total in our company. Also had wheel time in each type - mostly hauling asphalt in the 5 tons. There were 4 Mack ENDT673 powered A1 series dump trucks on the roster and I can honestly say we had absolutely no mechanical or reliabilty issues with those four trucks. The Macks performed very well and they were on the job every day. They are a tad slower than the Multifuels. The only thing I remember ever having to do with one of them was change out a voltage regulator. And the old relay type regulators were prone to fail on occasion.....The Transportation unit tractors and cargo trucks in Vietnam were nearly all Mack powered. There were a smattering of Multifuels in each line haul company but those were usually tagging along at the rear as bob-tails to use if a loaded tractor had a problem. They used M543A2 Multifuel 5 ton wreckers as well.The Multifuels have received bad press, and deservedly I think. Their lower ends were good, always held good oil pressure and I never heard one knocking, but the top ends and turbos got shaky after a few thousand miles. I loved the sound of the original "whistler" turbochargers. The Multifuels were worked in Vietnam, not sitting around in a motor pool like here in the States, and they did not hold up. It stands to reason.......465 cubic inches turning at 2600 rpm, squeezing out comparable horsepower to the 673 Mack turning at 2100 rpm. You'll be a long time wearing out Multifuel doing parades or sitting in the shed, but you will never wear out an A1 series 5 ton doing the same duty.If you don't latch on to that Mack powered 5 ton please send me the info.....thanks. Quote Link to comment Share on other sites More sharing options...
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