Centre Diff Locked

[k1c]

I'm starting tis one in a new thread 'cos I'm desperate, and time is short!

If anyone has any advice, tips or pointers I really would be very, very gratefull for your input.

Below is a post I attached yesterday to a previous thread started by leggyloo2.

Hi leggyloo2,

Read with interest your adventures with your central diffential being stuck, and thought that you may be able to help me. Bear in mind that I'm not stupid, and I do have some mechanical skill but I'm really not upto getting the motor in and out of one of these things in a month, let alone a day, so my hat is off to you.

I just got my wife's 99 RAV4 back from a mate who replaced the clutch, water pump and timing belt. Lo and behold the center diff is stuck in what appears to be much the same way that yours was. ie. pushing the button for the c-diff has the light come on, pushing the button to unlock the c-diff has the light off but the beeping signal start. No amount of backing up or accerating forward will unlock the !Removed! thing. I can hear and feel vacuum from the pressure swtches and hoses attached to the firewall, so they seem to be working OK., and appear to be in the correct locations. I currently can't see the other ends of the hoses though, or what they attach to. Unfortunately I'm working outside in very cold temps (10 degrees F. as of this writing), and the car is not jacked up. So my question is..... Is there anything on that side of the engine that I can get to, and that my buddy might have been into, or disturbed, that may have caused this problem, or am I just the victim of circumstance and coincidence? I haven't been able to locate the servo yet, or the 90 deg. bar off the tranny that you mention was the cause of your problem, so some simple directions or pics may help.

Sorry to bother you, but really any help at all would be very much appreciated as I'm stuck, and my mechanic friend is out of town for the next several weeks.

BTW, I'm in the USA so time differences may complicate talking a bit.

Thanks in advance, Chris Wolfe.

[anchorman]

Chris

Send Legs a pm. That way even if she doesn't look in she will get an email.

[k1c]

Thanks Anchorman, I sent her one already.

I did have a thought though, too late in the day to do anything about it I might add! If the centre diff is kept in the locked position by a vacuum, (I presume by the thing that looks like a break booster hanging on the end of the tranny), then disconnecting all the vacuum lines should allow the inner spring mechanism to unload the gears. No? I was so concerened with making sure that the hoses were properly connected that I didn't think to purposefully disconnect them. Or am I full of Horse Pucky?

[anchorman]

Thanks Anchorman, I sent her one already.

I did have a thought though, too late in the day to do anything about it I might add! If the centre diff is kept in the locked position by a vacuum, (I presume by the thing that looks like a break booster hanging on the end of the tranny), then disconnecting all the vacuum lines should allow the inner spring mechanism to unload the gears. No? I was so concerened with making sure that the hoses were properly connected that I didn't think to purposefully disconnect them. Or am I full of Horse Pucky?

No, disconnect the vac pipe from the servo. If the EP solenoid has stuck or frozen it could be opening the pipe to vacuum. Don't forget it may need rocking back and forth to make it drop out. The buzzer has a switch to warn it is still engaged - you are sure it is physically stuck?

Good luck.

[k1c]

Thanks Anchorman, I sent her one already.

I did have a thought though, too late in the day to do anything about it I might add! If the centre diff is kept in the locked position by a vacuum, (I presume by the thing that looks like a break booster hanging on the end of the tranny), then disconnecting all the vacuum lines should allow the inner spring mechanism to unload the gears. No? I was so concerened with making sure that the hoses were properly connected that I didn't think to purposefully disconnect them. Or am I full of Horse Pucky?

No, disconnect the vac pipe from the servo. If the EP solenoid has stuck or frozen it could be opening the pipe to vacuum. Don't forget it may need rocking back and forth to make it drop out. The buzzer has a switch to warn it is still engaged - you are sure it is physically stuck?

Good luck.

As sure as I can be. I can't get the wheels to spin upinder any circumstances on snow, ice or gravel, and the !Removed! beeper won't stop either. The handling just feels 'off', in the same way that my truck feels weird when its in 4wd....kind of stiff and imprecise, but very solid.. I daren't drive the thing more than a couple of hundred yards for fear of frying the transmission.

[anchorman]

Thanks Anchorman, I sent her one already.

I did have a thought though, too late in the day to do anything about it I might add! If the centre diff is kept in the locked position by a vacuum, (I presume by the thing that looks like a break booster hanging on the end of the tranny), then disconnecting all the vacuum lines should allow the inner spring mechanism to unload the gears. No? I was so concerened with making sure that the hoses were properly connected that I didn't think to purposefully disconnect them. Or am I full of Horse Pucky?

No, disconnect the vac pipe from the servo. If the EP solenoid has stuck or frozen it could be opening the pipe to vacuum. Don't forget it may need rocking back and forth to make it drop out. The buzzer has a switch to warn it is still engaged - you are sure it is physically stuck?

Good luck.

As sure as I can be. I can't get the wheels to spin upinder any circumstances on snow, ice or gravel, and the !Removed! beeper won't stop either. The handling just feels 'off', in the same way that my truck feels weird when its in 4wd....kind of stiff and imprecise, but very solid.. I daren't drive the thing more than a couple of hundred yards for fear of frying the transmission.

OK - well on with the checks then. Can you not get access to ramps just to make life easier?

[k1c]

Thanks Anchorman, I sent her one already.

I did have a thought though, too late in the day to do anything about it I might add! If the centre diff is kept in the locked position by a vacuum, (I presume by the thing that looks like a break booster hanging on the end of the tranny), then disconnecting all the vacuum lines should allow the inner spring mechanism to unload the gears. No? I was so concerened with making sure that the hoses were properly connected that I didn't think to purposefully disconnect them. Or am I full of Horse Pucky?

No, disconnect the vac pipe from the servo. If the EP solenoid has stuck or frozen it could be opening the pipe to vacuum. Don't forget it may need rocking back and forth to make it drop out. The buzzer has a switch to warn it is still engaged - you are sure it is physically stuck?

Good luck.

As sure as I can be. I can't get the wheels to spin upinder any circumstances on snow, ice or gravel, and the !Removed! beeper won't stop either. The handling just feels 'off', in the same way that my truck feels weird when its in 4wd....kind of stiff and imprecise, but very solid.. I daren't drive the thing more than a couple of hundred yards for fear of frying the transmission.

OK - well on with the checks then. Can you not get access to ramps just to make life easier?

Not ramps, but I have a jack and stands that I can put it up on. Unfortunately I likely can't work on the car now before Thursday which is my next day off.

My wife talked to someone today who told her that the problem is with the vacuum unit. It seeems to make sense that either thte hoses are connected improperly or perhaps the unit was reinstalled incorrectly afte the clutch job. Do you know if the vacuum assembly installation can be bodged? I don't know how these things attach or if there is part of the mechanism that could have been damaged when it was put back on. Given the lack of room down in there I may have to disassemble half the car to get at the thing.

Please say that it isn't so!

[anchorman]

Unfortunately not. My experience is exclusively with 4.2s and 4.3s so the rest is theory and case history from this forum. The EP valve and pipes should be easy enough to work out and then just a case of following it back to the transfer box. All I can tell you is that Leggyloo fixed hers without removing it all again if it does come back to the actual "hardware".

It obviously depends what is wrong but it sounds similar to Leggy's.

Short of being with you all I can suggest is you take the external bits out of the equation and even if push comes to shove and you really cannot see with th gearbox installed it isn't the end of the world if it has to come out again. I hope it doesn't come to that but if you work on that as a worst case - anything less is a bonus.

Keep your chin up and don't let it beat you.