I'm looking to get a higher output alternator for my truck now that I know my old alternator is kaput. I'm thinking about 130 amps or so. I'd like to go through my local autozone just so I can get it tomorrow and put it in. What I need to know is, what size alternator did you get? The guy at autozone said the only alternator they list for a 4.0L is a 95 amp one. Would one from a 4.2L f-150 work? Or another vehicle? What should I look for to make sure that it fits? Thanks so much everyone!

 

See if they have the 130 amp tremor alternator listed. If not, the exact same alternator is in several other larger trucks and will bolt right up.

 

What other larger trucks specifically? Do you know?

 

Anything with the same engine, probably more. Check older taurus for the 3.0l or explorers etc for the 4.0l. You'll have to do a few web searches to connect the dots, or let the autozone guys look it up. Worst case, scan through for matching engines in the air filter catalog, and then you'll have some options. Then pull the part that they say should match your truck, and then pull your guesses. Compare the two parts for identical mounting pounts, specs, etc. Nothing I would rush into, but shouldn't be too hard after a little detective work.

Good luck!

 

Thanks Michael. I picked up a 130 amp alternator from a 2001 F-150 4.2L. It has the exact same connectors and mounting points as my Ranger one does. The pulley is a tad bit bigger, but the belt tensioner in my truck's got plenty of slack so hopefully that won't be a problem. It will be going into my truck first thing in the morning as soon as there's light out, so wish me luck!

 

take the pully off the old alt and put it on the new one make sure the shaft is the same size

 

what is the ranger alt classified as? a 3G? 4G? 6G?

 

Would there be a problem if the pulley or shaft sizes are different? From what I can tell only the pulley is slightly larger.