Differentials gurus!!! Please check in

Please help me solve this puzzle as I’m new to the truck.

I have a 2018 4x4 TRD off road.

The rear diff is electronically control/engaged to be a locking rear diff, what is it when not engage? An open or an lsd?

And when 4x4 is on, what kind of diff is it for the front axle?

Thank you

 

Open Diff !!!!

 

Open Diff with computer simulated LSD

 

This.

 

Open diff in the rear? Or the front? Or for both?

If open diffs for both front and rears, then in 4x4 mode, I should not be having trouble making a 90 degree turn. But when I’m making a tight turn in 4x4 mode, the differential(s) is stopping me and the truck won’t move until I turned the steering wheel back.

 

The front is open diff and the rear is computer simulated lsd diff in 4x4 mode?

 

"4x4 mode"? Your truck has 4Hi and 4Lo. Depends on which range you are in. Front diff is always open unless you've installed an after market locker.

Rear will lock (in 4Lo only) when you push the locker button. Rear is open unless locked in 4Lo

 

On what type of surface does this happen? If you are on pavement or a surface with lots of traction you are binding the 4x4 system. likely the transfer case. Our trucks do not have center differentials.

 

During a turn the front and rear are scribing different circles and so need to move at different speeds. Binding is at the transfer case not the diffs in this case.

 

This might be helpful too. In the 'stickies' at the top of this very forum.

https://www.tacomaworld.com/threads/3rd-gen-traction-control-modes-explained.530695/

 

Thank you so much for all the responses and the link!!!

 

Yes it was in pavement

 

Avoid using 4x4 on pavement. It is okay only in a straight line, but still just try to not do it.

 

Yeah, you don't want to be in 4x4 in high traction surfaces whilst attempting to make a tight turn - it binds up because the front and rear axles need to turn at different rates, and the locked 50/50 split of the transfercase in 4hi or 4lo prevents this. And so, by forcing it through the bind, you're putting stress on the components to make it overcome the friction of the tires - making it hop/scrub

Front and rear diffs are open, with brake-actuated traction control

 

Thank you. I had it on 4x4 because it was pouring rain and the road were flooded with water and I forgot to turn it off when I got out of the rain ( Florida weather: rain at one part of town but sunny at another part of town). Since we are in this topic...my friend told me that I should drive with 4hi on, but to have it on just to get out or to get going, then turn it off afterward. I kept 4hi on because I feel safer so that I can avoid hydroplaning. What is your thought about keeping on 4hi n drive like I did or do it like my friend suggested, on then off??

 

Very useful knowledge info, thank you

 

We don't often get enough rain for hydroplaning in AK, but, when it has occurred I never felt the need for 4x4 - black ice being another story

I would say, if it's really that slick out, use it if you feel more comfortable, but primarily on straight or straight-ish sections of road -- like the highway. Curves, bends, and parking lot maneuvers are going to be what causes the bind-up.

These trucks do have abs, traction control and stability control, they would probably do fine in heavy rain in 2 wheel drive. Just stay out of the ruts and larger puddles if you can, and take it easy

hydroplaning largely comes down to your tire tread and it's water evacuation capabilities -- this being the primary factor of why you should replace your tires if they hit 3/32nds tread depth

 

I don't think I've ever hydroplaned the rear wheels, just the front. 4wd won't help there. Once your front wheels push the water out of the way, your rear wheels have traction anyway.

Side note: first time I drove in Anchorage, I hit a gigantic puddle at speed in front of Worthington Ford lol. Luckily I had mud tires and know how to drive on ice, that was quite the wakeup call...Hope it's fixed now, but everyone in that city probably knows which puddle I'm talking about haha.

 

open diff with a computer controlled ABS/traction/stability control systems. you can disable it to an extent... especially useful if you are offroading..

 

If your friend is talking about going in a straight line, that should be fine, it's when you start turning that the t-case will bind up. 4hi isn't going to keep you from hydroplaning, that's a function of your speed, the amount of water on the road and the tread on your tires. I don't see how applying power to the front wheels would keep you from hydroplaning.

I live in Colorado, and I'll use 4hi on pavement when starting on hills and there is snow/ice on the roads, or if there is enough snow on the ground that the wheels can slip a little going around corners. If those neither of those cases apply, it's 2wd only on pavement.