98 Ranger 4.0..4WD ex CabXLT Automatic..started the engine yesterday and my charge light came on and stayed on. Checked the guage and it showed no charging and then slowly began to charge and the light went out. If I rev the engine above 2,000RPM's the charge needle starts to drop but if I keep RPM's below 2,000 charging is okay. Is this the sign of a failing alternator? The belt only has about 20,000 miles on it and tension seems oksy

 

Probably. After about 90K the bottom brush starts to burn a hole on the slip ring. And at first, before it completely burns thru, 9 out of 10 people notice different rpm's have an effect. There are some cheap fix it yourself alternatives on you tube and the net, or get to your fav. part store.

 

put a voltmeter across the battery and see what it's putting out.

when mine went, i got a used alternator at a junkyard for $25 and it has been working fine for 3 years...

 

Daughters' zx2 did that at 3k rpms As soon as it touched 3k, the voltmeter would drop to battery voltage. replaced alt as it was over 100k miles.

 

alot of people say that. If you saw lots of em torn apart, like I have, it seems like they all got the same thing wrong with em.