Rear Diff Lock System

In February I bought a '17 Tacoma SR5, 4x4 with 32k miles. How do I know if I have a rear diff lock system? I have the manual open to page 576 talking about the differentials, their fluid capacities and the type of fluid, then there are all these call outs below the table saying For this, Except for......
On the data label on my driver door, I know I have GRN310L-PRTSHA. However, there are two call outs with GRN310L-PRTSHA under the table that are confusing me.
Call out #3 says: For GRN330L-PRTSHA, GRN330L-PRTLHA, GRN310L-PRTSHA and GRN310L-PRTLHA models without rear differential lock system. (this one takes 3.22Qts)
Call out #5 says: For GRN330L-PRTSHA and GRN310L-PRTSHA models with rear differential lock system. (this one takes 4.2Qts)
So the big question is, how do I know if I have a rear diff lock system or not? Its a difference of a whole quart of fluid.
Other simple questions: I now have 35k miles on the truck. For a guy that just drives his Taco regularly to work, errands and the once or twice a year trip, at what mileage interval should I drain/refil the front and rear diffs, transfer case and transmission? Thanks

 

You have a regular open diff.
No locker.

 

Only off road package has locker stock bro
If you think you have an aftermarket locker then I would assume there would be an obvious button somewhere.

Welcome to the forum!

 

The model code for your Taco is on the door sticker. Mine:


You don't have a locker, but changing the diff fluid out sooner versus later is a good idea the first time. Get the break in particles out. From there, follow the OM.

 

Pro's also have the locker stock, rightfully I suppose.

 

Pros are based off the offraod package just with a few more upgrades

 

I don't disagree, but some people really need it spelled out for 'em(no I'm not pointing at anyone specific, general statement) So adding that info doesn't hurt, and might even be useful to someone in the future.

 

Word

 

Its open diff with Auto LSD, which works amazing.