4.0 alternator on 2.5L

[Myles Cyncora]

Hello out there. Haven't posted for while but I'm stuck with no where else to turn. So back in summer of 2018 buddy told me to get an alternator. So I did. Now over 2 years later I am just realizing I think I got a 4.0L alternator i need one for a 2.5L. Is there a way to modify this alternator to make it work? Is there a separate pulley I can't get? 

Any help will be greatly appreciated 

[yxmj]

You need to clear up what you have...The alternator  will work with either motor..are you saying that you have an alternator with a pulley for a serpentine belt and you need on with a v-belt....What year is the truck?

[eaglescout526]

Do you have AC or no AC? Doesn’t matter too much if it’s 4.0L or 2.5L. But the no AC systems require a specific pulley. I got mine from Napa a few years back with the no AC specific pulley. 

[Myles Cyncora]

My truck with the 2.5L is 1987. The pulley on the alternator I got is about 1/2 inch short of being inline with the other accessories. I do not have AC.

[yxmj]

I think your problem is the alternator Bracket....not the alternator.....can you post a picture.....I have the same year and motor maybe i can help you out.

[eaglescout526]

This has been a problem before as I fought with this before adding AC. Renix 2.5L's without AC have a special pulley they need to be in line with the others. The bracket is fine, its the part stores that don't know the difference between the ACless models and AC equipped.

 

Pulley looks like this:

His  probably looks like this:

And this should be the bracket:

[Myles Cyncora]

That diagram is perfect I need the pulley attached to that alternator but I have the other pulley. Is there a part number for the pulley I need? Can i buy if separate? Or can I put something behind the pulley I have and space it out? 

[eaglescout526]

No. You will need to get the pulley with an alt combo sadly. That is how I sourced mine. Napa had one and I don't remember which one I ordered from them but it was a battle and a half to get the right one. If I can find my purchase history I will post the PN.

 

 

Nope, history on that is gone. If you go to anywhere else, make sure to have the counter monkeys verify that is has a six ribbed serp belt with a v belt pulley.

[Jeep Driver]

The 4.0 and 2.5 alt cases are not remotely the same. No, a 4.0 will not fit a 2.5. 

 

As for the pulley, bust the nut with an impact, swap pulleys, it's that easy. 

[Strokermjcomanche]

The bolt  mounting pattern is different from an 87 2.5 to a 87 4.0 . On The 2.5 the mounting bolts are directly across from each other, and on the 4.0 with one bolt at 12 o'clock the other should be roughly at 7 or 5 o'clock . Just changed one on my 87 with no a/c , no one had the correct pulley on theirs so I had to swap the pulley over .