paneal13

I have a 1991 with 90k miles on it now it is charging intermittently .sometimes works for a week sometimes an hour?
Cleaned voltage regulator mounts, ground to block ,cleaned battery post, Cleaned battery to block connection.
Any help would be appreciated
Pat

NE frmhnd

Did you try a new regulator? Usually they stick pegged. You could pull the alternator and have it checked.

paneal13

not yet trying everything I read before throwing money at it.
Had alternator checked and was told it was no good (advance) and on the way home it was putting out 14.5. If it wasn't intermittent would probably be easier to find.
Also noticed when going down hill it keeps jumping in and out of OD, but with the slightest pressure on the gas it stays in od??

NE frmhnd

Crank sensor on 92 or 93 could cause both, but not with an external regulator.

torquefan

On these trucks, the most common intermittent charge problems I have seen are from worn brushes in the alternator. They get short and pitted, then the springs won't hold them tightly enough against the slip rings for consistent current to pass. In your situation, I would try a new set of brushes first for the small amount they cost, and smooth the slip rings out a bit with some emery cloth. Hopefully that does the trick.