99 4Runner Rear Locker?

[nowashburn]

A few months ago I purchased a 99 T4R (6cyl, auto, sr5) and noticed that when turning there was a tugging or pulling coming from the rear when giving it gas. I went under the truck to inspect and make sure nothing was broken and as expected, everything checked out fine. I'm by no means an expert mechanic but the only thing I can think of at this point is that there is some kind of locker or posi rear on the thing.

My questions are:

1. How can I tell if there is a locker or posi rear and if there is, how can I tell which one it is?

2. If so, Is this a factory option or did the previous owner have this done aftermarket?

3. Isn't there usually an on / off switch for this type of thing?

Thanks in advance for any help!

 

[rubbman]

Check for a rr diff lock button.

 

[nowashburn]

Check for a rr diff lock button.

no button

 

[cordrayj1]

Jack a side up and try to spin a wheel by hand

Sent from my MB860 using Tapatalk

 

[fire931]

Yea if it's a factory elocker then there would be a button in the dash, or you should see the motor hanging off the drivers side of the differential. If none of that is present then it's possible they previous owner installed something in it. Simple check is as said above, jack up a rear tire and try to spin it by hand.

 

[nowashburn]

Thanks for the quick responses. No, there is no button or anything else that is noticeable / additional that I can see on the axle. However, when doing the suggested spin test, both wheels do spin in the same direction. I guess this means that there is some kind of aftermarket locker in there?

I guess I should be happy about this "upgrade" but are there any negative effects with having this? I imagine gas mileage and tire wear would be worse?

Thanks again for the help.

 

[KidVermicious]

I guess this means that there is some kind of aftermarket locker in there?

That's exactly what it means. Now leave one tire on the ground, or otherwise prevent it from spinning, and try and spin the other tire backwards. If it does, then you've got an automatic locker. That's not horrible - you probably won't notice any abnormal tire wear as long as you keep them rotated. It'll push you through corners when you're on the gas, as you noticed, and it'll act all sorts of hinky on snow or ice, so be ready for that.

If you can't spin the one tire backwards while the other is planted, you've got a spool, or a welded diff. That will definitely increase tire wear, and exhibit even worse road manners, and I'd recommend taking it out, or finding somebody who wants a spool to trade you their 3rd and a little cash.

 

[nowashburn]

Wait, so.... I have both sides up now and one side spins freely while the other side won't budge either way. again, if I gas it, they both go in the same direction. Does that make sence?

 

[nowashburn]

Nevermind, it behaves exactly as described in your first scenario. Looks like I got an automatic locker, awesome :driving: . Thanks again for the help.