The Larger Ground wire(Negative) from the battery is often connected to a Starter Motor bolt, which is on the bellhousing.

But that larger cable can also be connected to the engine block.

 

 

Flashing OD light means there are transmission Codes in OBD2(computer) memory, you need to get those codes, they will all start with P07.. or P17..

Make sure the wiring harness on the drivers side of transmission got plugged back in correctly, loose connector will cause the flashing light

Include the year and engine size for your Ranger, so we can be more specific

 

 

1995 to 2000 Ranger with 3.0l will have a 4R44E automatic, 4-speed
2001, and up, 3.0l got the 5R44E, 5-speed, so if you have a late 2000 you could have the 5R

Doesn't matter much they are the same transmission, and same as the 4R55E or 5R55E

Google: flashing OD light 4R44E

Loads of posts and possible fixes
But I would go to auto parts store and have them read the codes, WRITE THEM DOWN!!!!

"I think code was............." is not helpful, and worse than no code at all, lol.

 

 

 

Thanks for the update

Pump??