Starter replacement

The bolt size is 13mm. Here is a guide to help you see what you are in for when doing the job and diagrams to show you what it will be like for your truck:

https://www.2carpros.com/articles/how-to-replace-a-starter-motor

INSTALLATION
1. If equipped, position aluminum spacer to rear of starter.
2. Position starter motor to engine.
3. Support starter and loosely install three mounting bolts.
4. Tighten 3 bolts to 43.4 Nm (32 ft. lbs.).
5. Position wiring eyelets to starter studs and install nuts. Tighten small nut to 6.2 Nm (55 in. lbs.). Tighten large nut to 13.6 Nm (120 in. lbs.).
6. Install protective rubber boot over stud.
7. Lower vehicle.
8. Connect battery cables to both batt

Check out the diagrams (below). Please let us know if you need anything else to get the problem fixed.

Cheers

A long extension through the inner fender. Make sure the battery is disconnected.

Disconnect battery ground cable(s), then remove wiring connector from starter.
Remove starter mounting bolts, then the starter.
Reverse procedure to install, noting the following:
Torque B+ terminal nut to 6-9 ft-lbs and solenoid terminal nut to 45-65 in-lbs.
Torque starter mounting bolts to 50 ft-lbs.