Buying a M939 at auction: What to look for and to be prepared to fix

[Tinstar]

Whatever you choose.
Highly recommend replacing the original 60A alternator asap.

I had read about them frying, but since mine was working fine, why bother....!!

Mine literally fryed and smoked about two weeks ago, taking with it a new Power Control Box and my ABS module.
Also possibly my CTIS controller.

$900 later.........

Brand New Delco-Remy 33si 100A alternator
Correct Factory Cummins Alternator Bracket
Gates Green Belt.
New PCB
Rebuilt fried PCB (spare)
Brand New ABS module
Still searching for new CTIS controller

Replace it quick.
You will be money ahead and your battery's will be much happier.

Contact SS member: 74M35A2 For alternator

 

[71DeuceAK]

I've heard the alternator thing too, but thanks foe the heads up nevertheless, Tinstar! I've also read multiple recovery stories where the stock alternator was trying to charge dead batteries (totally dead) and subsequently fried itself.

 

[Tinstar]

Exactly

The new alternators will charge them without self destruction.

Anyway
Glad you know.....

 

[71DeuceAK]

Think the stock one would be OK getting the truck started to drive onto a step deck trailer, then off? Later, once stored at a connection's place, a couple new 8Ds could go in.

 

[Andrmorr]

Just take 2 good batteries with you, take out the 4 old batteries, hook up the two good batteries and drive away. As long as the alt sees the correct voltage that the two good batts will provide, it won't be working overtime to charge 4 dead batteries...don't take the chance on the condition of the old batteries...my truck was newly rebuilt in 2010 but by the time I got it the military Hawker batteries were all but ruined from sitting since my truck only had 36 miles on it. I drove it home 400 miles from Atlanta and the batteries were just as weak when I got home. I found out about the flaky M939 alternators AFTER I drove it home... Your truck will start just fine on 2 batteries (common mod) unless you have other issues...My truck starts so quick now on 2 batteries I don't even hear the starter...

 

[Stranger]

That is good advice. I ruined my Deuces alternator this weekend slaving it to an M923 with two bad batteries.

 

[porkysplace]

Just take 2 good batteries with you, take out the 4 old batteries, hook up the two good batteries and drive away. As long as the alt sees the correct voltage that the two good batts will provide, it won't be working overtime to charge 4 dead batteries...don't take the chance on the condition of the old batteries...my truck was newly rebuilt in 2010 but by the time I got it the military Hawker batteries were all but ruined from sitting since my truck only had 36 miles on it. I drove it home 400 miles from Atlanta and the batteries were just as weak when I got home. I found out about the flaky M939 alternators AFTER I drove it home... Your truck will start just fine on 2 batteries (common mod) unless you have other issues...My truck starts so quick now on 2 batteries I don't even hear the starter...

2 batteries probably work alright in North Carolina but he is taking the truck to Alaska where he will want all 4 batteries.

 

[Andrmorr]

2 batteries probably work alright in North Carolina but he is taking the truck to Alaska where he will want all 4 batteries.

See post #24...He asked about getting the truck on the trailer and to the storage facility...that was what this recommendation was for...when he gets to AK he can do the Alt mod and load up all 4 batteries...

 

[Tinstar]

Think the stock one would be OK getting the truck started to drive onto a step deck trailer, then off? Later, once stored at a connection's place, a couple new 8Ds could go in.

Yes
getting it on and off trailer.

Not sure about the 8Ds
Others will chime in about those.
I do agree you will need four battery's in Alaska


I run Hawker 6AGM in all my MVs.

 

[simp5782]

2 8D's will do him fine. I am going over to four 8Ds just cause of the driving i do.

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[71DeuceAK]

Only issue is that I won't be the one first picking it up, so just bringing two 8Ds with me isn't really an option...

 

[simp5782]

Only issue is that I won't be the one first picking it up, so just bringing two 8Ds with me isn't really an option...

Parts stores are every where. Napa,oreilly. Even amazon

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[71DeuceAK]

How 'bout if the shippers are the ones picking it up, with the correct paperwork of course? Maybe replacing an alternator is still a cheaper route than getting them shipped there or whatever?

 

[simp5782]

As a person who picks up. I always bring 2 good batteries cause they have to be able to get it off their truck at drop off. I don't like to change batteries way up on a trailer. Especially no heavy ones. Its just my stye to help the customer out. After i drop it. Its their problem. I tell them what they need to have

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[71DeuceAK]

Right...

Hypothetically would you even consider towing it back from Ohio to Wisconsin? Would consider paying someone on here to do it instead, who for one thing knows their way around these trucks.

 

[Hard Head]

Find one as close as you can to home! Even if you pay 2k more you will still be cheaper in the long run especially if you can inspect it first! I have my vehicles flat bedded to me even as close as 100 miles away due to break down issues. I don't want to hurt or kill someone with a braking, axle, or tire blow out issue! Towing expense is not cheap either on a break down. Never leave home without your dash camera! Some folks slam on brakes in front of you for stupidity or insurance reasons now. Especially if they think the Govt will take care of them.

 

[Tinstar]

Find one as close as you can to home! Even if you pay 2k more you will still be cheaper in the long run especially if you can inspect it first! I have my vehicles flat bedded to me even as close as 100 miles away due to break down issues. I don't want to hurt or kill someone with a braking, axle, or tire blow out issue! Towing expense is not cheap either on a break down. Never leave home without your dash camera! Some folks slam on brakes in front of you for stupidity or insurance reasons now. Especially if they think the Govt will take care of them.

I have a dash camera in all my vehicles.
Civy and MV
Difference being, in my regular vehicles, I run the dual camera model Garmins.
Recording front and rear.

Cheap insurance and video/Audio proof

 

[simp5782]

Right...

Hypothetically would you even consider towing it back from Ohio to Wisconsin? Would consider paying someone on here to do it instead, who for one thing knows their way around these trucks.

I will tow them from anywhere. My 5 ton is trustworthy enough to do 7,000miles a month loaded.

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[71DeuceAK]

How much a mile would you ask?

 

[simp5782]

How much a mile would you ask?

923/931 trucks are 1.90 a mile. 927/934 trucks are 2.10 a mile

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