Re: 99 f350 7.3l
It's a sign that something is wrong. The codes will tell you where to start looking. Without the codes all I can tell you is that something is wrong.
The places that read codes free CANNOT read these codes. You need either a good independent shop or a Ford dealer.
Former Ford Automatic Transmission Engineer
“The good thing about science is that it's true whether or not you believe in it.” ― Neil deGrasse Tyson