1999 Rav4 Gearbox Operation

November 2, 2009

Hi Me Again

I am stuck here and need some info on how this Rav 4 Transmission works .Somehow it all does not make sense to me .

I have been searching the internet as well as the Toyota dealers around here high and low for info but was unable to find any . There is so much talk on limited slip diffs , traction control , Viscous drives – name it - but nothing is making sense here .

I don’t know why the info on the rav transmission seems to be kept as a state secret .

Even the workshop manuals don’t tell you exactly what is happening inside the transmission of these vehicles .

My Rav is a 1999 3 door version with a 5 speed transmission . Also has ABS . The vin number is SXA10-0033851 .

From what I can gather the manual transmission is a front wheel drive until the centre diff is locked , The it becomes a AWD with equal power to the front and rear wheels . The Automatic version is a permanent AWD which will allow more power to the rear wheels if and when needed due to slipping .

Allow me to tell you what I did :

First I checked if the diff lock works by jacking up the front of the vehicle , putting it into gear and “drive’ it . Only the front wheels rotate .

Then I engaged the diff lock , applied the hand brake and when I let the clutch come out carefully I can feel the vehicle stalling - so the diff lock works .

Then I jacked up the rear vehicle and rotated the rear wheels - they rotate into opposite directions- so it’s a normal diff and not a limited slip diff.

But if I jack one rear wheel only and try to rotate it - it locks up , it does not rotate the rear prop shaft , even if the diff lock is off .

Surely it should now be free to rotate ?? If the diff lock is off.

Why would it do that ? Is the centre diff of some limited slip type ? Has the ABS to do something with it ?

I would appreciate it if you could help me with this .

If possible could you also forward your answer to this directly to me to johnjnam@yahoo.com because I cant always get into this site from this end of the world .

Thanks again and wishing you a super day

John

:unsure:

November 2, 2009

If you push it hard enough it will turn. Don't forget that the 4.1 is permanent 4WD with a lockable centre diff'. That means with both wheels up one turns one way and the other the opposite but with one wheel in the air you are now trying to turn all of the transmission up to the centre diff and it will be very stiff to turn.

November 2, 2009

dear happy chappy in a sunny clime..............

your RAV is as ancs says a permamnenetentnent 4 wheel drive so drive goes to all 4 wheels. If a wheel is off ground then you will lose drive.... engaging the 'diff lock'basically means that it locks the drive to both front and back. Theres no limited slip diff

I use the diff lock when racing my RAV on 1/4 mile drag starts/runs - which means when the front wheels lift off the ground, then the drive to the rear wheels still propel the car forward. The drive only fails when the tyres spin on the tarmac. I use the diff lock for the whole run and it works ok right up to the terminal speed of 105mph., and not the recommended 50mph

However as ancs says, there is a considerable drag on the transmission whilst in 4 wheel drive mode - from memory I think its about 50bhp.

November 3, 2009

If you push it hard enough it will turn. Don't forget that the 4.1 is permanent 4WD with a lockable centre diff'. That means with both wheels up one turns one way and the other the opposite but with one wheel in the air you are now trying to turn all of the transmission up to the centre diff and it will be very stiff to turn.

Hi Anchorman and Bothwell

Thanks for your reply I really appreciate it . But it still does not make sense !

The Rav's with automatic transmission are all permanent 4WD. But my Rav is a 2.0 L 1999 Rav4L and has a Manual 5 speed box and a 3sfe engine .

If it was permanent 4WD then it should surely try to jump off the jack when the front wheels are both lifted off the ground and I "drive 'it . Then only the front wheels turn.

The back wheels only come into operation when you lock the centre diff.

Therefore I say that with all 4 wheels on the ground and centre diff lock in off position one should be able to rotate the rear wheel and propshaft - if the gerabox is in gear .

The centre diff should disconnect the rear axle totally .

And my centre difflock works - I tested it a few times - it engages and disengages fine.

I just wish I could get hold of a manual or site which gives an illustration of the gearbox and differential .

As said none of the manuals say anything .Looks to me that the Rav transmission is kept a state secret .

Am a mechanic myself , but this one goes against all theories of gearboxes .

Other than that the car is fine - I just recently bought it . Had a bit of bad luck as it was using about 2 litre of engine oil on 700 km ( engine only has 140 000 km )

I stripped the engine and all oil rings were seized up and the whole engine was severely gummed and varnised up inside . The car was regulary serviced by a toyota garage here and I was told that they only put syntetic oil in their engines and not the 'rubbish" that we guys put it . -

I completely overhauled the engine myself and put my "rubbish Castrol GTX 20w50" mineral oil in and now she runs like a dream .

So much for syntetic oils and their "extended" service intervals !!!! but I guess that is another topic and can of worms .

Thanks again and happy Ravving

November 3, 2009

No, your vehicle won't try and drive off the jack with the front wheels off the ground because you have the centre third diff. Now if you engage it the vehicle will try to climb off the jack as long as both rear wheels are on the ground. So to summarise if you have a permanent 4WD and ANY single wheel spins in the mud the car will stop. If you lock the centre diff you only guarantee that one front and one rear wheel will turn but as soon as you have one front and one rear spinning you are stuck again. You would need cross axle diff locks to drive all four wheels in the mud or limited slip diffs to resist but not stop cross axle spin.

The centre diff in normal permanent 4WD only prevents inter-axle wind up where the axles will fight each other.

The lack of a decent manual frustrates us all. The 4.3 has a superb and fully detailed manual. The 4.2 has a good manual but not definitive and the 4.1 has a DIY style Haynes and another US manual which is similar which you can only really refer to as reference for servicing and torque settings. As far as repair goes they are utterly useless so you need to "feel your way around" as a skilled mechanic would do (this is where he/she uses experience to strip and repair componenets) or maybe Toyota do a manual that can be ordered but usually these things are hundreds of pounds.