Okay, here is the circumstance:
1)When I back up my trailer in the yard, to get there, there is a curb. With my burb and the 4runner, back wheels go over no problem. When I hit the front wheels, I just give it a bit more gas and up they go. However, if there is a great amount of resistance, say....a trailer or wheels are turned...

This crazy noise similar to a large truck engaging the clutch comes out of the rear end. First time I thought it was the front hubs not engaging because I was using 4wheel low. However, this time I kept it in two wheel. Well the noise happened and backed off. Put the trailer in and brought the runner back out onto the same spot.

This time I recreated the scenario. Turned the wheels, put up against curb, gave it gas and wala...noise! So here are my thoughts. I engage the locker to see if that aleviated the noise. Nope, every time. Which brought me to this conclusion:

1)If there is a great amount of tourque is applied to the rear end at certian angles, will it press on the locker?
2)If the locker is engaged, can fail to turn the wheels if force is greater at the wheels than at the drive shaft?

Does anyone else experience this? Just for comparison, if it goes in 4lo, all the issues go away. Help!

 

its not the rear suspension or springs creaking is it? mine makes popping and creaking noises.

 

my rear leafs creak as well i sprayed them real well with P/B blaster and it stopped for me

 

we have coils in the rear.

 

Anyone? No one else has this problem?

 

I never had to work on differentials or have any experiences with what you described, but if I would have to guess and if noise sounds like grinding gears then I would say that is what it is: grinding gears. And I hope that I am wrong and you will not have to change rear end in your 4Runner.
Maybe somebody else will pitch in.

 

It is not a grinding noise, rather a whining noise.