Transfer Case and Transmission Issue: Can’t Shift to 4L/4H

Anyone Experiencing this …
2021 TRD Pro, I can’t shift to 4L or 4H seems like only when cold, after I drive a while, no problem.
Once I try to shift to 4L or 4H when cold, I can’t shift to 4H or back to 2H or from N to P.
When this occurs I feel the gears start to grind (very, very slightly ‘cause I know it’s coming) in all attempts to shift the transfer case to any position including the transmission back to P!
It seems like the transfer case gears and transmission are spinning on cold startup which makes no sense because I am trying this from a cold start and not driving.
Of course I will be seeing the dealer but thought I’d check with you guys too.
TIA!

Clarification; I think I over-explained the issue, causing confusion, my bad. This is my 5th 4WD vehicle so I have close to 800k miles driving these fun machines. So hopefully to simplify … never an issue shifting from 2H to 4H. At cold-start, when stopped, foot on the brake, and in neutral, I cannot put her in 4L. Once this happens I cannot return to 4H, 2H or get her into 4L without transfer case gears grinding at any attempt Also, once this happens I cannot put her into Park without grinding the transmission. When she is hot, e.g. driven 10 miles or more, all is fine and works as it should.

 

You have to be swift with the shifter. You should also be on the move when going into 4wd high and back into 2wd. Let off the throttle a little to make the shift easier.

 

2Hi to 4Hi should be a pretty seamless shift, but you need to be moving in order for it to happen.

To shift into for a 4Lo, you first need to shift into 4Hi, then neutral, then 4Lo. I find it makes for a smoother shift if you put it in neutral while the vehicle is still moving at one or two mph, and then shift into 4Lo at that speed.

Think of it like a bicycle. You know when you shift gears on a bicycle, you have to be pedaling in order for the gear change to actually take place. The transmission and the transfer case behave in a similar manner.

 

Every time I've seen instructions for 4H to 4L (and back) it states the vehicle must be stopped, transmission in neutral, and brake on before shifting. That's also what I've found works for me.

 

Wurd. Going into, or out of 4L, I would be stopped, and trans in N. Just me... From 2H to 4H, and back to 2H is another deal.

 

Yeah, I read that too. I've tried it both ways, and the shift is smoother while barely moving.

My old grand Cherokee was the same way, the 4lo shift was much easier when the vehicle was rolling a little bit.

 

Try changing the fluid out in the transfer case. I found on this forum the Ravenol 75W oil that replaces the Toyota oil. My shifts are buttery smooth after an oil change. I also use Archoil 9100 a friction modifier. My 2019 Tacoma with the electric shift was awful going into 4lo. I changed the oil to Ravenol and it really helped.

 

? OP

 

rip

dat

bitch

(from 4Hi into 4Lo and vice versa)

 

Yep, a good solid motion is what it was designed for.

And if nothing else, over time and mileage the magnets and filter will do their job.