I have an sr without electronically locking rear differential.

So as the title says, I have a stock 2018 sr and it does not have a locking diff. Does anyone here know if it's possible to add the electronics/wiring harnesses to enable the rear diff lock or is it something that cannot be added to the sr model? Google has been unhelpful.

 

Probably better off just adding an aftermarket locker. Look up ARB if you want an air locker or Harrop if you want an elocker

 

A locking dif is a lot more than just a wiring harness.

 

Have you taken your truck off-road? I wheel a bit and the Sport has no issue keeping up with the OR’s. I keep to green and blue trails, what keeps me off blacks is armor, lift and tires. I do have the yellow wire mod, but that’s as much a state of mind as anything else.

 

Toyota Electric Locker
The Toyota Electric Locker is a selectable locker that replaces the entire third-member and may require axle housing modifications. Made by Toyota and offered on 1993 & newer model trucks, the "E-Locker" uses an electric motor and worm drive assembly to engage or disengage the locker via a shift fork and collar. It is a proprietary design that is not compatible with open differential components. Therefore we can only offer this locker fully assembled as shown in the picture. It is a reliable and popular choice and is offered in standard or high pinion configurations. Axle housing modification and custom wiring is required for trucks that were not originally equipped with an E-locker from the factory. Please click the image for more information.
From Marlin Crawler website.

 

ARB and never look back.

 

If you off road hard enough to need a full locking capability, go for it. I offroad my Sport with good results using a Trutrac torsen limited slip. Works great on / off road and has real utility in slick conditions on street. $1,100 ish installed, very happy with mine

 

This. Take it off-road and see if you'd really need it. I've only really used the locker a handful of times on the OR. Even when I just had the SR, I was amazed I got through obstacles with just 4x4 low.

 

This was extremely helpful, thank you!
I'm new to the offloading world, and I'm aware that a rear diff lock is more than a wiring harness, the reason I asked is because the trd off road and sport are all very similar and I wasnt sure it couldn't just be added.

 

You can't just buy the Toyota e-locker and add it to your differential, the TRD Tacomas with the e-lockers have a different size housing so it won't fit properly. Only way to do it would be to swap the entire rear axle with a rear axle that has the e-locker diff, or go the aftermarket route and find the right aftermarket locker that fits your diff (ARB or Harrop are the two big selectable locker aftermarket brands).

 

I have had e-lockers on a LX450. Nice but the ARB is much better, the air supply can be upgraded to inflate tires as well (I have the ARB twin under the hood), engage quicker, and should cost less to install. Someone correct me if I'm wrong, bet less maintenance too.
If one sourced used parts, they may be able to do oem for less, but I doubt it.

Having said that, I have not yet installed one in my sport, and may never will. I have spent a lot of money on suspension, skids, air compressor and more. The air compressor handles the tire re-inflate task (allowing more traction while off road), the suspension provides greater flex (more contact with articulation), and I have a 12k winch and recovery gear, which not only can get me unstuck, but can help someone else as well.
Don't get me wrong, lockers are great to help you not get stuck in the first place, or get unstuck from some incidents, but as other's have said, do some assessment and determine if you really need it. If so, or you just want too, go for it!

 

Makes sense, I was unaware the models were that different but I'm glad i know now, thanks!

 

only time I need locker is:

going slow as to not break things as i sneak over rocks. I don't
have enough momentum to get over something slippy (usually moss) and
the auto-lsd and a-trac can't handle it. then e-locker and this usually
fixes it...locked rear make the ass really seek traction and ...can crawl away

if that all fails then I have to go get momentum and hope for happy scraping sounds and not ka-Bang sounds

a-trac does fix about everything though...trucky I rarely lock, '99 4runner I use locker a lot

 

The TRD e-lockers are cool, and I like that I have one, but ARB is an all around better locker from the start.

The ARB lockers (or most aftermarket lockers like the Harop, afaik) have a better engagement system. With the TRD lockers, it doesn't engage instantly so you have to futz around with it, sometimes drive forward or back in a slight "S" to get it to engage. The ARB is instant.

As for A-trac, that's cool too, have it on my SR5 4Runner, but that's a LOT harder to add aftermarket, lol. When the chips are down, I'd still take a locker over A-trac, even if you could add it aftermarket.

 

I have a SR as well. Like others have said, try it off road first. I don't have that locker crap and I have been on the beach, snow, New Jersey pines in the mud/sand and never needed it. I feel if the road is that bad requiring a locker I wouldn't want to go down it. Off road lightly and have fun don't beat up your expensive vehicle. This is just my opinion because these trucks are too expensive to trash.

 

for what it is worth, lockers allow you to drive extra slow and careful,
and this is where you end up slipping on rocks and roots, getting stuck..not
enough speed and tire might slip. so hit the locker and keep going slow
but now you have extra rear end creeping and grip.

I never considered the locker as anything but
'I want to protect my expensive turd, so Imma going slow and may get stuck from being too slow' get out of jail card...

 

Lockers give you more traction no matter what speed you're going. Sometimes that's good, sometimes not. Part of becoming a better driver is learning which situations a locker is beneficial, and when you should turn it off. That's why a selectable locker is better than a spool.

Sure, not having a locker might mean you will need to use momentum to get you through an obstacle that you'd otherwise be able to just drive straight through.