Hello I'm new an had a question about my 1999 f150 I have an abs light on a check engine light and my over dive light is flashing when I hit the brakes it shifts hard going from 321 computer says it's a trs but that just tells the computer what gear it's in could that has an issue with it?

 

Are you saying you have 3 separate fault lamps involved?
CEL,
Shift lever lamp,
and ABS.
If yes, they have to be investigated as separate issues.
.
The TRS offers a digital based signal to the computer in Binary or Octal base numbering. The trans is totally electric control for fluid path control.
Don't treat it to lightly.
We need to sort out the issues to be sure what's going on.
List all codes you know about as a start.
Good luck.

 

Take it to someone who knows what they're doing.

 

Sounds like it's the speed sensor in the rear end, it's located just to the left of the differential.
https://www.rockauto.com/catalog/mor...nid=517&jpid=0

Denny