Piece of string stretch around the belt route? Buy both and return one (funds permitting)? Take tools and change in parking lot (sometimes they are not happy about this, might have to use a lot nearby)?

 

It is very simple, if you have ACE, buy the long belt if not the short one.

 

OK. Got shorter belt since it turns out I don't have ACE. Changed it, and no problems since. Maybe the belt just slipped real bad on the alternator causing the car to think it needed "limp mode"? Who knows...

Anyway, seems fixed, for now. Gimme 2 more weeks. I'm sure I'll have another problem.

 

IMHO you might want to get battery tested at one of the parts stores. If alternator belt was slipping, not charging enough, so much that the tranny ECU detected this and decided to limp home, your existing battery may be starting to have problems (or dirty connectors). Usually they do the test for free with a small machine, battery stays in the car.

 

I will have the battery tested, but it's only about a year old, and it's the best one we could buy. I highly doubt there's anything wrong with it.

 

The tranny ECU will limp home, turn on a light, and may set a code if input voltage below 9 volts when truck is running. Good battery with reduced charge from slipping alternator or wire connector corrosion issues could do that.