Alternator?
 

Just bought a 2010 F250 6.4. While driving the RPMs and Speedometer will drop to zero and several warning lights will come on (brakes and seat belt). That lasts for a few seconds then everything returns to normal. I'm thinking alternator, what do you guys think? Thanks in advance.

my vote is on either a ground or other loose electrical connector.

alternator would light up you battery red indicator.

My wife drives my future truck. Just went down to the local boozery to watch the Lions loose, and took this rig because I have my 99 brakes gutted.

At start up, both rpm and tach needles did a little dance until the glow plugs timed out. Then everything was ops normal. My running voltage is 14.3-4 so my alt is good. Truck sat in the garage for four days prior and my batteries are 5 years old.

I would consider (with these electronically finicky trucks) Getting a fresh set of good batteries if your due.

If they're older, save yourself the headache. I'm going to.

Denny