M915A1 Alternator

[deuceman51]

Well my alternator and transformer died a very smoky death the other day and I was wondering if any of you guys have found a better civy 12/24 alternator for your M915s, M916s, ect? I don't really want to shell out the $575 the local places want for a replacement one. I want to keep mine stock as I use it with military trailers and slaving other trucks. I'm working on a solution on my end, but figured I would ask in case someone already found something that worked.

 

[NDT]

Just had the same thing happen. Alt shop told me the 12/24 system has fallen out of favor, and that I should swap in a 12 volt starter for $200. I also did not want to do that. In my case, just the transformer was cooked and the Leece Neville 12 volt 85 amp alternator part checked out OK. Luckily I had a core 915 series alternator from a GL sale and the transformer was good on it. So I am running, but still looking for a better solution as well. The Freightliner 915's have some form of 12/24 solid state converter and I think that might be an option for retrofit.

 

[reb87]

Ive been able to get new replacement transformers and my alternator has always been ok. Ive cooked two of them so far and believe that it happens if you accidentely short the batteries when jump starting.
Southern Automotive Wholesalers, Inc.

I bought mine from ebay( I picked up a couple extra for future probs)
2920-01-102-8586 TRANSFORMER-RECTIFIER FOR 915A1 TRUCK | eBay

 

[reb87]

current link
Transformer Rectifier P/N: SAW11028586 | eBay

 

[wreckerman893]

I had good luck with Southern Automotive when I had to replace the rectifier on my M915.

 

[Andy1234]

I had good luck with Southern Automotive when I had to replace the rectifier on my M915.

As have I.

I was able to send them payment via Pay-Pal and had it in my hands 3 days later.

I had a local alternator rebuilder re-do the alternator, install the box and test it for another $200, so total out of pocket cost was $380.

And, just because I can...

Andy

 

[Irv]

I converted to all 12v but have an option to add the 24v side for trailer lighting if I ever want to. See my thread at http://www.steelsoldiers.com/5-ton-mods-hot-rodding/76252-m915-converting-all-12v.html

Basically, you chuck the 12/24 alternator and install a commercial 12v unit. Replace the starter with a 12v unit (common as dirt). Tie 12v and 24v systems together. Fine, except that the 24v trailer lighting is now 12v. However, you can purchase a converter that takes in 12v and puts out 24v (see the thread) and insert it in the lighting circuit at one point before the relays. It's obvious on the wiring diagram and I'll be happy to help anyone that wants to do it. This way, you are generating the 24v as if it were generated by the alternator. Cost is under $100. Well under.

I put 3 Group 31 batteries in parallel and it starts fine, in temperatures down a bit below freezing (as low as it has been tested). Put 4 batteries in, if you like.
Irv

 

[Hooty481]

My truck came with only 2 batteries. The truck starts fine but will this give me any trouble down the road with my alternator. Has anyone else run like this for very long or at all?

 

[Irv]

I think it would be just fine. It might even be a little easier on the alternator since it never has to try and charge up 4 batteries at once. You may notice it being harder to start in cold weather, but I started mine down near freezing with just two batteries. I tossed in a third, just to have a little margin.

On the plus side, if everything is 12v, then I can get a jump start from a civilian dump truck, etc. I can also install a common 12v winch.
Irv