5 ton Mack Turbo Diesel-Good Engine, Problems?

[steelblue91]

Im looking into a early 1970's 5 ton (M39 so the owner says but im also told by others it a M54/M81, I haven't physically seen it yet to confirm the model but it has the Mack Turbo Diesel engine. Are these Mack Turbos a good engine? Any known problems & what are some things I should look at or look for if any? I have no idea if these engines have plenty of power or if they are junk. Any common problems with them & is there any articles in magazines etc written about these Mack Turbos? Thanks guys.

 

[Fredo Corleone]

The problem with the mack 673 in the A1 5 tons is the parts are tough to find. They have good power compared to the lds 465.

 

[armytruck63]

It is not an 800 series if it has the Mack engine, it would be the M54A1 type. The engine is very desirable for its longevity and wide power band. Unless the truck or engine is thrashed in some way, it sounds like a great find.

 

[steelblue91]

The problem with the mack 673 in the A1 5 tons is the parts are tough to find. They have good power compared to the lds 465.

Ok, thanks! Looks like I better go view it to see what model it is. As I mentioned-the owner says its a M39 but other people are telling me different.

 

[steelblue91]

It is not an 800 series if it has the Mack engine, it would be the M54A1 type. The engine is very desirable for its longevity and wide power band. Unless the truck or engine is thrashed in some way, it sounds like a great find.

Thanks armytruck63! Going to view it so I know exactly what model it is for sure, owner says M39 while others are telling me different (M54?)

 

[Evil Dr. Porkchop]

The m54 is part of the m39 series of 5 tons. m54 is a cargo, m52 is a tractor, etc. The originals were gassers, the a1 series had mack engines, the a2 series had multifuels.

 

[Warthog]

As PC stated above M39s are a series of trucks. There are different versions of the trucks within the series

Deuces are M44 series
Early 5tons are M39 series
Mid 5tons are M809 series
Late 5tons are M939 series


http://olive-drab.com/od_mvg_www_deuce_m39.php

 

[steelblue91]

The m54 is part of the m39 series of 5 tons. m54 is a cargo, m52 is a tractor, etc. The originals were gassers, the a1 series had mack engines, the a2 series had multifuels.

Ok-thanks! Its a tractor so it must be M52 is what people were saying it could actually be....with the Mack Turbo Diesel. I have no idea why people are questioning the model (M39 as the owner tells me it is). A friend of mine know's the owner & told me about this truck. So I called him out in western N.Y. & talked to him about it. Next is to go & see the rig!

 

[steelblue91]

As PC stated above M39s are a series of trucks. There are different versions of the trucks within the series

Deuces are M44 series
Early 5tons are M39 series
Mid 5tons are M809 series
Late 5tons are M939 series


http://olive-drab.com/od_mvg_www_deuce_m39.php

Thank you very much for the link! I noticed they have a M39 & a M52 listed....Im assuming that the M39 "cab & chassis" is just the cab & frame while the M52 "tractor" is the same with a 5th wheel hook up for towing trailers? Is that the difference between them?

 

[jhooah]

You should find the frame and suspension beefed up in the tractor versions (and wreckers) the components for the most part are interchangable, but the frame and number of springs, possibly ratios are different depending on the mission of the truck.
The 809 series started with M52's, but were refitted with different engine and transmission (Cummings) and had a resulting longer hood and fender sheet metal added to them. the 800 series also changed other things like the dash, where emergency cutoff was added as well as changes in gauges.
It takes a little bit of studying to really get the vehicle lineage correct as far as gasser-diesel-upgraded diesel-change to diesel-change to drivetrain-change to vehicle layout goes.
Some drink fuel or smoke heavily and run slower (my M543A2 Wrecker for example crawls for a mile) than others, so don't fall in love with the one you'll learn to hate.
W Winget