This section comes up in Chapter 3 when you play as Sideswipe.
You can only use grapple 5 timers the sixth will force you to restart the whole chapter, although restarting a checkpoint prior will reset the counter. There is a checkpoint in the middle of the chasm that comes in handy but remember the 3 you used to get to that point remains meaning you have 2 left even when you restart that checkpoint.