Durango Alternator Swap

Mercury

TJ Enthusiast
Original poster
Joined
Jul 18, 2018
Messages
313
Location
Louisville, KY, USA
Hello, all!

I've been reading a bunch of threads on this swap and I'm confused about the Jeep year requiring different plugs and apparently some issue with what side the alternator sits on.

I have a 1999 4.0 and I just found that the junkyard near me has several 01-04 4.7 Durangos in stock. My alternator sits on the left hand side if I'm havingy the front of the Jeep.

Is there a certain Durango alternator I need to look for to prevent having to change the plug? Is it going to be compatible with my Jeep at all given the alternator location? I've done my research but I'm still left with questions.
 
probably better off buying a reman durango unit at napa.
it's not going to be a upgrade unless you actually need more output.
 
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probably better off buying a reman durango unit at napa.
it's not going to be a upgrade unless you actually need more output.

I definitely need more output. I'm trying to save my money to buy a nice 240 amp one down the line so I'd rather not spend $200 on one that I'll replace within the next year, but for now I could use a boost.
 
What are you planning on running at over 2kW of power... in a TJ?

Over 2kw stereo. At the moment I'm running about 1.5k but I'll be upgrading to a 1500w sub amp in the next year and that'll push me to about 2400k. Plus I like that the hairpin alternators will put out a lot more at idle so I can winch faster (I've been told) and run my stereo with less battery drain.

On my current alt I get headlight dimming even at highway speeds so I want to get an alt with a little more oomph. Then I can invest in a better battery over the next one or two months.
 
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Amperage draw surges.

I was Just firing from the hip, and keeping things simple. The amp surge goes high, voltage drops low. The caps are indeed used for short bursts, not for long sustained extremes.

The OP @Mercury should also seriously upgrade and overhaul his grounding system. The stock chassis to battery ground will be seriously insufficient to handle what he is claiming, and he probably needs to undo and clean the existing grounds as well.
 
I still can't hear/understand 2/3 of what my wife says.

I think the question becomes is that necessarily a bad thing? 🤣

I don't actually listen to it that loudly. I prefer clarity and tight response instead of pure SPL. It's just with the road noise and lack of hard top you have to push an insane amount of watts to feel the bass. Even 750 is barely noticeable because of the soft top.

I was Just firing from the hip, and keeping things simple. The amp surge goes high, voltage drops low. The caps are indeed used for short bursts, not for long sustained extremes.

The OP @Mercury should also seriously upgrade and overhaul his grounding system. The stock chassis to battery ground will be seriously insufficient to handle what he is claiming, and he probably needs to undo and clean the existing grounds as well.

Yes, that's the next step. I have a Big 3 kit that I need to fashion contacts for (I need to pick up a hammer crimper) that I want to use to replace my battery cables. I wanted to last year but I caught up with other repairs and then it got cold.
 
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I’m with the earlier post about biting the bullet and getting the better alt. There’s the “buy once cry once” mentality, or my preference “if you can’t afford to do it once, you can’t afford to do it twice”
 
I’m with the earlier post about biting the bullet and getting the better alt. There’s the “buy once cry once” mentality, or my preference “if you can’t afford to do it once, you can’t afford to do it twice”

I'm definitely going to, but it's hard to pass up $35 to get a significantly higher output. That'll free to my budget to buy a better battery then within the next year get the HO alt that I want.
 
I have a 99 4.0 with the alternator on the passenger side. I found that junkyard alternators don't work on the 99 because of the different orientation of the mounting ears. You might want to check yours before you buy.
 
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