Engine/Transmission (1994 - 1998) Which Alternator?

[Northrunner]

My 1998 12 valve 3500 needs a new alternator. What amp is the original one that's in it? One parts store tells me they came with a 120 amp, another store tells me they came with a 136 amp. Does it really matter much? Are the new Denso ones that "Larry B" sells for $359. 00 really worth that price? Thanks for the help...

 

[Grizzly]

I'd call any Dodge dealer and ask the part dept.

 

[fest3er]

My 1998 12 valve 3500 needs a new alternator. What amp is the original one that's in it? One parts store tells me they came with a 120 amp, another store tells me they came with a 136 amp. Does it really matter much? Are the new Denso ones that "Larry B" sells for $359. 00 really worth that price? Thanks for the help...

I believe stock is a 136A alternator. Consider that each of your two intake heaters draws about 100A. I suspect you'd want the slightly larger alternator for two reasons: one, to decrease the battery drain when the heater are on and, two, to more quickly recharge the batteries between heater cycles. OK, it's not a big difference, but it's still better than a poke in the eye with a sharp stick or being stuck just once with not-quite-alive-enough batteries.

 

[CCiatteo]

When my alternator was acting up I went through the same mess and ended up just having mine rebuilt locally, which I felt much better about after getting conflicting info and outrageous prices for new stuff, rebuilt stuff, premium rebuilt stuff and super duper uber premium rebuilt stuff.....

I paid $155 or so for a full and complete rebuild and had it back 1 day later. That was 1 year and 15K miles ago, no complaints.

Too answer your question though, I ended up with the 136amp deal for the reasons mentioned above.

 

[LVJUNIOR]

$359 sounds like a lot for a stock replacement. I am saving for a mean green alternator they put out a lot more amperage and are built very robustly for $399

 

[hsmith]

Check out Motor City. New high output units for about half that price.

 

[LVJUNIOR]

the problem with the motor city as well as most other high performance alternators is that they are designed for gas motors and don't deliver the higher output ratings until well over the cummins redline RPM. Make sure if you get a high output it delivers its peaks under 2000 rpm preferably less

 

[hsmith]

I didn't realize that. Good info to remember. Thanks

 

[LVJUNIOR]

hsmith I am happy anytime I can share what I have learned. I have used the information in many of your other posts. Thats why I love TDR

 

[KYOUNG]

I bought one at Oreillys for $150 worked great so far.....

 

[DieselDoghouse]

Ours are 135A for the reasons noted above. These trucks came with either a Bosch or Nippondenso unit. If yours is a late production like mine it is likely nippondenso. I believe I paid somewhere around 130. 00 for an autozone replacement with lifetime warranty.

 

[Hammer]

I have one of the Mean-Green units and its a very nice unit that has worked flawlessly since its install. Yes they cost a bit more but in my opinion it was well worth the money I paid for it... ... Andy