Alternator went out.
Replaced it.
Crank the truck, everything’s fine.
After it runs for about 90 seconds “check charging system” notification pops up.
Turn it off. Crank it again. Same thing.
Checked the alternator. Says it’s good.
Any ideas?

 

Most of the time, aftermarket alternators never work properly, or never work at all.

 

Get an oem or reman unit.

 

that's what i would do

 

X3 .. you need a Motorcraft re-man..our trucks are very picky about the voltage regulator in the Alt.

 

Yep. You need OEM/Motorcraft reman

 

If you can afford it, try and get a new OEM unit. I still don't trust remans to last as long as a new unit.

 

For what it's worth, I've had good luck with a brand new Remy alternator from Rock Auto. No problems yet and it's been nearly a year.

However, to echo statements above by others, I tried another aftermarket unit beforehand and had to return it. I decided to choose Remy because of their OEM roots.

 

Which Remy? The 92551, right? (I have that in a saved cart)

 

Yes, the 92551 is what worked for me.