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Discussion Starter · #1 ·
Took the rig out to play at a little spot at the edge of town that mixer trucks used to pour unused cement. Engaged 4wd and went about messing round. Got onto gravel road and pressed the button to disengage, rolled forward and then back and the beeping stopped. But today climbing a hill in town on pavement, i dropped the clutch a little too soon and felt an enormous buck from the rear end. No spinning tires just a hard hit and a launch into space.
Does anyone have a diagram of how the central lock works (engage and disengage)so i may diagnose what is happening? I checked for damage at the ujoints and cvs, but didnt notice anything unusual.
Any help is appreciated.
 

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'99 RAV4.1, 3MZ-FE, E250F 4x4, Torsen Dif
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How far back did you reverse, you must backup until you "feel" it disengage, it can take several feet (10 to 30 feet maybe more if on a hard surface). Back straight up, if you turn the wheel it puts tension on the system and may prevent it from unlocking and may cause damage.

This is what it says in the manual for a 99 RAV4.
To unlock the center differential:
1. Put the front wheels in as straight ahead a position as possible.
2. Push the center differential lock switch once again and check that the indicator light in the instrument panel goes out and that the indicator buzzer stops sounding. The indicator buzzer will sound while the center differential is being unlocked. It stops sounding when unlocking is completed. Sometimes complete unlocking of the center differential may take longer. If unlocking of the center differential is not completed, check the area around you for safety, then accelerate or decelerate, or move the vehicle backward.
NOTICE: While the indicator buzzer is sounding, do not make turns, and do not put the vehicle into a garage. This may damage the locking mechanism and the drive system.

I found that it can stop sounding but still be locked.
 

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Discussion Starter · #3 ·
Interesting. I backed up about 5-10ft. Light and alarm turned off somi thought i was alright. Ill give it a go again tomorrow. Thanks for the help!
 

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Engaged 4wd and went about messing round.
But today climbing a hill in town on pavement, i dropped the clutch a little too soon and felt an enormous buck from the rear end. No spinning tires just a hard hit and a launch into space.
From what you posted, I believe that the differential has been successfully unlocked.
When you pressed the button, you did not engage 4WD, you locked the center differential.
The RAV4 is 4WD when there is enough traction on the road (on pavement for instance). All four wheels drive the car and the open differential ensures appropriately different speeds between the front and the rear axles when turning.
When you lock the center differential, each axle gets the same amount of power. If it was still locked, you would feel the vehicle to be difficult to turn.
To test it, go on a slippery surface and make a tight turn. Then press the button and make the same turn again. You should be able to tell the difference.
 

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To test it, go on a slippery surface and make a tight turn. Then press the button and make the same turn again. You should be able to tell the difference.
I should clarify that I mean tight turn with minimal speed. For example, stop, turn the wheel all the way and accelerate for 4-5 metres. Then do the same thing locked. You should feel the steering to be heavier. The difference is more apparent on pavement, but I can't advise you to do this.
 

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Discussion Starter · #7 ·
Thanks Mick, i understand the variation with a locked transfer case, having owned a couple jeeps and other 4x4s. I was unaware that the ravs were awd until locked into 4wd. I was under the assumption, based on another site, that they were fwd until locked into 4wd.
 

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Discussion Starter · #8 ·
Well i dragged the rig out again and ran with the center locked and unlocked and noticed the difference straight away without even turning. There was a hum and a sluggish feel whenever i began to make a turn. Disconnected and it went away. I appreciate the help. Im glad the system is operating normally.
 
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