Clicking noise when cranking

[kozakvod]

Not all the time, but at times it will on first morning crank.

I pulled the battery box cover and saw that I had one that was leaking, okay there's my problem. Bought a new battery, replaced, checked all other connections, buttoned everything up, same problem again next morning.

Pulled the cover, started looking more closely at the batteries and noticed another had a slight bulge on one end and at this point since it had been almost 2 year since I replaced the batteries I bought 3 more, now all new. Checked the connections at the starter, they were clean and tight, buttoned everything up and it started fine, no clicking for a few days and then Wednesday morning this week, started it up, same thing again, clicking during crank.

I'm hesitant to replace the starter as I can't confirm it's bad/going bad and maybe that's the problem? But I always know that click is generally a cause of low voltage coming out of the batteries. So if that is the case, what might I be missing? Or is it possible I have a starter going bad? I have owned this truck since 400k miles, currently at 645k and I have not changed the starter myself and have no record of the starter ever being changed.

Truck / Engine: 2014 Pete 388 / cm2350