Fun In The Snow!

[jedi134]

Hi Anchnorman, I am interested in the Rav 4.3 part time 4x4 system, On the Haldex system the main clutch is bathed in a special mineral oil, which is seperate from the rear diff oil, They call this system a multiplate wet clutch system.

Now looking at the pdf you posted, It says that the Rav 4.3 is also a multiplate wet clutch system, So this to me implies that there is an oil/liquid that the main clutch plates are bathed in? Does the 4.3 rav share the rear diff oil EP90 with the multiclutch or is there in fact another fill/drain plug as on the Haldex system? which will need to be replaced at some point, every 20k on a VW

The picture attached is of the Haldex system, this is a completly different unit bolted onto the rear diff, which both use different oils. here is a Link to the parts needed for a Haldex system, a filter and a tub of special mineral oil. Now belive it or not VW missed this service for years even though it stated it in the owners manual, they were just checking the rear diff oil thinking it was all 1 unit, when infact it was 2 seprtate units bolted together.

Im just wondering whether Toyota have done the same? as on a fixed 4x4 system as on the 4.2 rav and the old vw`s pre haldex, there will only be 1 set of rear diff fill/drain holes. Now with the newly introduced part time 4x4 system on the Rav also stating its a multiplate WET clutch system, will there infact be an extra fill/drain hole for the multiplate wet clutch oil??????? It was also the change over from fixed 4X4 to part time 4x4 that VW missed it for quite some years. Although Audi new about it????

I hope you can understand what i`m talking about, It would also be nice to know the manufacturer to the Rav 4.3 unit. Sounds and looks very like a Haldex system, which are now fitted to a vast amount of 4X4 by various manufactures.

[anchorman]

It is very similar in its operation but infinately more simple as it is actuated by this electrical ball ramp/helix set up.

Only time will tell us how long they will last but I can assure you it is completely self contained with its own "wet clutch" oil supply and there is no way to add oil to it. The diff has its own supply of regular EP90 oil so in some respects you could say there is a lot less to worry about with the RAV.

The Haldex unit operates by differential drive shaft speeds and is far more complex. The fact that your previous dealers didn't know how to deal with it doesn't surprise me in the least. The special oil is virtually the same as ATF but Haldex prefer you to use theirs for obvious reasons although the spec is probably available.

The RAV unit just unbolts and you throw it away when it wears out but eventually they may become available as a recon unit when there are enough in circulation. I can tell you that unit does not concern me in the least and I do not anticipate any snags for probably the life of the vehicle unless somebody does astronomical mileage. I'd pay no attention to it if I were you and don't let it influence your decision. Go and drive a new XT-R or SR and see how nice they are.

PS - I believe I know Anders Lindstrom - he has an old yankee pick up truck that he restored if it is the same one. Haldex have a small engineering department and one of the engineers there is a young lady who I shall just say that as well as being very clever is very, very, very nice in all respects.

[jedi134]

A Har! So the "Electromagnetic Coupling" on the Rav is the Haldex equivalent?? and this contains the wet multi clutch and oil in a sealed unit? I presume it also has some wires/electronics coming from it which is not shown in the diagram.

I have also notice from the diagram that the Rav`s rear diff has 2 drain plugs? 1 on either side, below both right and left drive shafts. Usually you just have 1 in the center at the bottom of the diff. Any reason for the 2? How do you fill it up?

[anchorman]

Fill it up like this;

diff_oil_inst.pdf

I usually have photos but its so easy I never bothered. The plug on the passenger side is for draining and the one on the drivers side is for filling - it just happens that the diagram calls them both drain plugs. I will take some photos soon so you can see it.

Sit tight........

[jedi134]

Thanks Anchorman, I presume the other drain plug which is not visable will be higer up too?

[RupertRAV4]

Just don't forget that the thing that makes the biggest difference is how you drive any of these vehicles. All these new electronic aids will only get you OUT of trouble - they won't stop you get INTO trouble in the first place- that is down to how you drive them. They only help because they react so much quicker than most humans to this going wrong. And that 4WD makes no difference when you're already going sideways....!!

[MarsKy]

Fill it up like this;

diff_oil_inst.pdf

I usually have photos but its so easy I never bothered. The plug on the passenger side is for draining and the one on the drivers side is for filling - it just happens that the diagram calls them both drain plugs. I will take some photos soon so you can see it.

Sit tight........

Meant to say: Quest - Freeview Channel 38 - are showing a series called "A 4x4 is Born". Guy building a 100 inch wheelbase Range Rover/ Land Rover hybrid. He did differentials and gearboxes yesterday (29th December). Good explanation of how they are built-up and work. Quest usually repeats at the weekend. Chasis, suspension and roll cage tonight, starts at 6pm.

[rambler]

Just don't forget that the thing that makes the biggest difference is how you drive any of these vehicles. All these new electronic aids will only get you OUT of trouble - they won't stop you get INTO trouble in the first place- that is down to how you drive them. They only help because they react so much quicker than most humans to this going wrong. And that 4WD makes no difference when you're already going sideways....!!

hi rupertrav4

i drove about 30 miles through 4-5" of snow to a walk in suffolk recently,although i have all terrains on mine,it never put a foot wrong....i never went sideways,..i personally think 4wd makes ALL the difference to ensure you dont go sideways.

IF vehicle is being driven correctly

'full time 4wd' is SUPERB

would never have anything else :D

[Catweazle]

Happy new year everyone.

Does anyone know if all the 4.2 models have VSC as the blurb from Toyota only mentions it on the XT4 and above? Does this mean that the poor XT3 driver has to fend for himself? Also, what about the 4.1s? Does the GX have the equivalent of VSC?

[llith]

Back to thread topic. Found some snow today , had some fun in the RAV , solid handling.

Happy New Year to all / Blwyddyn Newydd dda i bawb

[Plutus]

Happy new year everyone.

Does anyone know if all the 4.2 models have VSC as the blurb from Toyota only mentions it on the XT4 and above? Does this mean that the poor XT3 driver has to fend for himself? Also, what about the 4.1s? Does the GX have the equivalent of VSC?

The XTR has VSC as well as the XT4 and 5. I don't think it's on the XT3.

Will VSC make a lot of dfference in the snow?

Full time 4 wheel drive certainly seems to (and all 4.2's have this).

[anchorman]

The VSC will help if you lose control whether in the snow or otherwise.

I guess we have to accept that VSC is a feature that hasl become standard but was only on some models during the transition period.

You still have a better fighting chance than the majority of cars even without it.

[anchorman]

Been to Hull today and that car of mine has behaved impecably - been up hills and lanes that you would not believe. It is my most favorite ever car and I cannot praise it enough.

This evening I nipped down town and as I turned out of the drive the back end shot sideways and it dug into the gate post. With daughter in the car I bit my lip but my once mint RAV now has a battle scar on the rear wheel arch. Never mind! I'll see what the local chips away man is made of.

[local hero]

Sorry to hear of your little bump Anchs.. I am sure you will soon have it back to its former pristine condition Its nice to hear everyone praising their Ravs.. I sold my former 4.2 to my brother, who lives in a very hilly part of Oldham, he has just been down to Cornwall for Xmas + phoned me last night he cannot believe how good the Rav is + was full of praise for it, again it has been faultless since he has had it + has never put a foot wrong in the recent weather..I think because of the likes of Clarkson etc who are too quick to knock (soft roaders) we don't fully appreciate just how capable they are..When i first got my 4.2 I had a trip to Bakewell Derbyshire where the police use Rav4s, I got into conversation with the driver of one who reckoned of all the police cars he drove the Rav would get him places even so called serious off roaders couldn't manage, Recently i called at RRG Stockport, which shares its very steep entrance with an adjacent LR dealer, + I kid you not, a Range Rover sport was struggling up the icy slope which my rav barely noticed + I have yet to use the diff lock..so lets hear it for our little Ravs.. Stew

[chatman]

Recently I called at RRG Stockport, which shares its very steep entrance with an adjacent LR dealer, + I kid you not, a Range Rover sport was struggling up the icy slope which my rav barely noticed + I have yet to use the diff lock..so lets hear it for our little Rav's.. Stew

For all those RR Sport owners...who may look in with envy here......

Go Buy a RAV4.......

Here's the proof....

[Davrav]

Never mind! I'll see what the local chips away man is made of.

If he is half as good as Sven, my local 'Chips Away' guy, you should have it back to rights with no trouble

During the summer our local council 'Weed' operative managed to ding my upper rear quarter panel behind the rear side window with a hoe and a rake that left two small but highly visible dents at eye level - the dipstick was driving down the pavement on his service buggy that was loaded with hand tools poking up at the back, iPOD in, sunglasses on and totally oblivious to his surroundings.

Sven [from Svindon] spent about 3hrs on my drive and charged me £130 but I cannot see the join so to speak.

Good luck Anchs

[rambler]

Recently I called at RRG Stockport, which shares its very steep entrance with an adjacent LR dealer, + I kid you not, a Range Rover sport was struggling up the icy slope which my rav barely noticed + I have yet to use the diff lock..so lets hear it for our little Rav's.. Stew

For all those RR Sport owners...who may look in with envy here......

Go Buy a RAV4.......

Here's the proof....

yeah,good ol rav4's...small, reliable, versatile,comfy and economical 4x4.....well pleased

[cabcurtains]

22" wheels and low profile road tyres, i wonder what effect this has on a 4x4's capability

[rambler]

22" wheels and low profile road tyres, i wonder what effect this has on a 4x4's capability

yep'couldn't agree more

bet its never taken off-road.....apart from in photo,....and its stuck

bloomin low profiles,on a 4x4...whatever next....

even with all that electronic stuff,if tyres wont grip,,you aint movin nowwhere !

[cabcurtains]

22" wheels and low profile road tyres, i wonder what effect this has on a 4x4's capability

yep'couldn't agree more

bet its never taken off-road.....apart from in photo,....and its stuck

bloomin low profiles,on a 4x4...whatever next....

even with all that electronic stuff,if tyres wont grip,,you aint movin nowwhere !

I have tried to explain this to my wicked step mother, she has the same car with the same size rims albeit different wheels and was complaining about a lack of traction! The conversation moved onto her not understanding/listening why my old mans Kia Sorento is better with its 16"'s and chunky tyres.

Not sure why i bothered

[chatman]

JC proved the point brilliantly in tonight's TG program....Used the hideous BMW X6 monstrosity to prove why do car makers make a 4x4 and then make it no good as a 4x4...or at least have some good traction... X6 is one such vehicle.... and as I said to the lady driver of the RR in the ditch (which was being winched out by a Land Rover :unsure: ) best change those racing slicks for some proper tyres..... :lol: :lol: she said she did not know what all the traction buttons where for...and by the look of the hole she had dug in with wheel spin...no one else in the RR did either.... :rolleyes:

O and if any one else is wondering....the tree stump survived...only minor scratching and a little chip.... :D :D :D With all this freezing ice we have had...I'll see tomorrow if it has claimed any more victims..... :lol:

[Babybadger]

So Anchorman, I think you also owned a 4.2 before the 4.3.

Which do you think has the "best" 4wd sytem - the 4.2 or 4.3?

The reason I ask is that I will be going off road once or twice per week in the coming year (farm tracks, across fields etc) so I'm wondering if the 4.3 auto diesel will be as good or better off-road as the 4.2.

I haven't had a 4.2 although I've worked on several but that is a good question!

To summarise;

4.2 - permanent 4WD. There is no third diff and transmission wind up is avoided by allowing the transfer box to pick up on the front axle diff. On early versions with square fog lights they had a limited slip rear diff to reduce the risk of one wheel slipping on a low friction surface. On the later versions with round fog lights they use the traction control system to limit cross axle slip on both front and rear axles and there is no limited slip diff.

4.3 - 4WD on demand via a multi plate clutch on the input of the rear axle. This can distribute the drive anywhere from zero RWD to a ration of 55/45% front to rear distribution.

The 4.2 is beautifully simple and reliable means of sharing the drive between axles and of course the benefit of having both axles driven is an aid to traction and stability. The disadvantage is that it causes a certain amount of drag and can affect economy.

The 4.3 has the benefit of being able to disengage the rear axle at will and not only that but bring it in at a variable rate. This allows the full benefit of being a simple FWD for maximum economy and to turn on the rear axle by an amount to best deal with traction or stability. Remember the vehicle sets off in 4WD but as the speed increases and the demand for torque reduces the drive to the rear axle deminishes. Now if you are cruising at 50mph it will almost certainly be in FWD but now the way the coupling behaves is different. If accelerate to say, pass another vehicle, the rear axle will be engaged by a similar amount to how hard you are pressing. Think of the 4WD coupling being attached to your accelerator foot - press hard and you will bring in the rear axle fully. Feather the accelerator and the rear axle may just be applied slightly.

Which is best crossing a field? There probably isn't much to choose but the downhill assist control on the auto may be a great help. Just keep in mind that any RAV is a compromise and you can't really expect a vehicle that will return 40mpg ish at 70mph to cross a field like an old nail of an LR with all lockable diffs, a low box and knobbley tyres.

OK - we have established that the system can assist traction and now most of us have had a play in the snow you can see that it is very good compared to all those front or rear wheel drives slipping about and getting under the feet. However, if you want to consider where the real benefits are you have to think about how it can be integrated into the VSC (vehicle stability control) and it can be taken a step further by integrating the steering, traction control, brake assist and ABS. This is what Toyota refer to as "Integrated Active Control".

So. The RAV has electric power steering. It does away with the pumps and belts and hydraulics and is only used when needed so aids fuel efficiency. A strain gauge in the column measures the amount of effort being applied and can give more assistance when parking and less when on the road - this improves feel. But it also means that it easy to measure steering angle and it also means that if you do get into a skid it will determin which way you need to turn to correct the skid and either assist you to turn it the correct way or resist (but not prevent) you to turn it the wrong way. Under the passenger seat there is an acceleration and yaw rate sensor which is attached to the main ECU. Imagine you are on a road travelling at 50mph and the road bends to the right. It knows how fast you are going and it knows how tight the bend is by the steering angle sensor in the column so the sensors under the seat check to see that they are experiencing the correctly mapped amounts of acceleration and yaw. If it does then the system sleeps with one eye on the weak link (err - thats you). Imagine the road is slippy and when you enter the curve the vehicle begins to drift out to the left. The ECU cannot reconcile the lack of inertia from the under seat sensors with the speed and the steering angle - it knows you are in trouble and now the sleeping giant is awakened. Like it or not, the ECU can think quicker than you can and will take the vehicle virtually out of your hands; It may in any amount:-

-take the power off the engine

-resist you turning the steering the wrong way but assist you to turn it the right way

-apply any one or up to all four of the brakes without you touching the pedal depending on what kind of skid you are in order that re-align the vehicle on the intended course (for instance applying one inner rear brake may assist in pulling the car back into line in the case of a rear wheel skid - and yes the computer mapping tells it whether you are in a front or rear wheel skid). Not only can it do this but it can apply different brakes by different amounts

-if you are braking because you need to reduce the speed at the same time as turning the bend it will look at how you pressed the brake pedal. If you stamped on it then it will consider that an emergency and will generate brake pressure by up to double on your behalf. However, if you pressing on the pedal too hard is having an adverse effect on regaining control it will completely over-ride that and may release the brake

-use the ABS system to modulate (apply and release) any brake that is on the limit of adhesion

-either bring in or take off the drive to the rear axle to assist the situation - in some cases a little and in some cases fully

-in the case of an impact, deploy one or more airbags, take the slack out of the seat belts and on the latest RAVs allow the back of the seat to follow you forward thus reducing whiplash

It can do any one or any combination of these things while you are deciding what day it is and why that orange light is flashing. Only when it establishes that all the parameters suggest the vehicle is under control will it hand it back to you. As Chris said recently, it cannot defy the laws of physics and as long as things didn't go badly wrong then you hopefully won't end up down at A&E getting the Hawthorns out of your gums and the dry stone wall out of your rib cage.

The later 4.2s have VSC but only the 4.3s have active control. To my eyes the 4.2 looks nicer - especially the 3 doors but in my humble opinion, if you are able to choose between a 4.2 and a 4.3 you can expect the latter to go some way further in reducing the risk or effect of an accident. It is reasonable to expect that handling and performance have been improved. Off road? I don't know but probably similar and maybe that downhill or hill start assist may just swing it???

Sorry for rambling.

Keep rambling, so what about a 4.1? Are the manual and autos the same? Are they true 4wd when the centre diff is locked?

Thinking of getting a 4.1 auto for my mum. Do any 4.1 models have LSD on the rear?

[anchorman]

Well bb, I don't profess to be an expert on 4.1s but this is what I know (bothy might add something)

The 4.1 is a little different in that it has a third diff. It is fairly conventional in that it has a transverse engine and box with a transfer box with a prop shaft to the rear axle. The big difference is with the transfer box in that it has a third diff in there which is lockable. So. Drive is always transmitted to the front and rear wheels but if a rear wheel spins in the mud the whole car will stop because the third diff will spin. In this case the third diff can be locked by pressing a button on the dash. This operates an EP solenoid (electro-pneumatic) which opens up manifold vacuum to a piston operated selector and the third diff gets locked. You need to remember that even when locked you can still get one front and one wheel spinning as they have their own diffs which are not lockable and do not have a limited slip feature. However, it still provides surprisingly good traction and providing the vehicle isn't virtually buried, you can usually rock them out of a drift.

Now the tricky bit is disengaging the third diff! Any gears that are in mesh will hang on to each other if there is load on them. If you drive down a hill in over-run (so not under power but with your foot off the galloping iron and the engine providing braking effort) and with your foot off the clutch and try to push it into neutral, you will find that it doesn't want to go. This is due to the load on the gears. Now, if you put your foot on the clutch it will go (obviously) but if you just feather the accelerator it will also go easily. This is because you release the load off the gears. If you continue to press the accelerator so it is under power you will do the same and will be unable to push it into neutral. Now back to the third diff. Locking the third diff will provide more traction on poor surfaces but on a good surface you can get both drive axles fighting each other as the need to turn at slightly different speeds because they all turn through a slightly different radius. This in time can cause transmission and tyre wear and in a tight turn the wind up can be enough to even resist motion (known as "tight corner braking"). For this reason you should not run on a good road surface with the third diff locked. When you press the diff lock button to disengage it, the vacuum is exhausted but a buzzer will sound until the diff lock disengages and it won't disengage if the gears are loaded. Now back to the first lesson! To disengage the diff quickly you can either rock the car gently back and forth but with a bit of practice you can do it "on the hoof". As I said before you can just feather the accelerator so it is just dawdling between power and over-run and it should just drop out.

To summarise;

4.1 - Permanent 4WD with lockable third diff but no limited slip diffs and no traction control. It is possible to get one front and one rear wheel slipping.

4.2 - Permanent 4WD with no third diff as the transfer box picks up on the front diff. Early models have a limited slip diff on the rear axle only but later models (equiped with VSC) have done away with the LSD and rely on the traction control to assist in cross axle wheel spin.

4.3 - Automatic and variable 4WD. No third diff as wind up is controlled by the slip in the drive unit relaxing any load. The vehicle ALWAYS sets off in 4WD BUT if the vehicle is started from rest with the steering turned the drive to the rear axle is significantly reduced. This automatically eliminates "tight corner braking". Cross axle spinning is controlled by the traction control. On all models above XT3, the drive system, steering, ABS, traction control and VSC are all linked and will work in unison (Toyota Active Control).

General - We have to remember that these are "soft roaders" and real off road capabilities are not comparable to vehicles with a low box and lockable diffs (in each axle) and lockabled third diffs. However, they generally provide much better fuel consumption and comfort and have gearing to allow high cruising speed. They also have very acceptable dynamics and will handle in some cases better than a saloon car.

In all cases we have to remember our old cleche - all the electronics in the world won't allow you to defy the laws of physics.

[Mike JD]

Now that is a very clear and comprehensive explanation. Much clearer that I could get from the Haynes bible I have just got for Christmas. I'm very grateful

Mike D

Below freezing already on Dartmoor. Roll on getting that clutch fixed so I can use the RAV

Well bb, I don't profess to be an expert on 4.1s but this is what I know (bothy might add something)

The 4.1 is a little different in that it has a third diff. It is fairly conventional in that it has a transverse engine and box with a transfer box with a prop shaft to the rear axle. The big difference is with the transfer box in that it has a third diff in there which is lockable. So. Drive is always transmitted to the front and rear wheels but if a rear wheel spins in the mud the whole car will stop because the third diff will spin. In this case the third diff can be locked by pressing a button on the dash. This operates an EP solenoid (electro-pneumatic) which opens up manifold vacuum to a piston operated selector and the third diff gets locked. You need to remember that even when locked you can still get one front and one wheel spinning as they have their own diffs which are not lockable and do not have a limited slip feature. However, it still provides surprisingly good traction and providing the vehicle isn't virtually buried, you can usually rock them out of a drift.

Now the tricky bit is disengaging the third diff! Any gears that are in mesh will hang on to each other if there is load on them. If you drive down a hill in over-run (so not under power but with your foot off the galloping iron and the engine providing braking effort) and with your foot off the clutch and try to push it into neutral, you will find that it doesn't want to go. This is due to the load on the gears. Now, if you put your foot on the clutch it will go (obviously) but if you just feather the accelerator it will also go easily. This is because you release the load off the gears. If you continue to press the accelerator so it is under power you will do the same and will be unable to push it into neutral. Now back to the third diff. Locking the third diff will provide more traction on poor surfaces but on a good surface you can get both drive axles fighting each other as the need to turn at slightly different speeds because they all turn through a slightly different radius. This in time can cause transmission and tyre wear and in a tight turn the wind up can be enough to even resist motion (known as "tight corner braking"). For this reason you should not run on a good road surface with the third diff locked. When you press the diff lock button to disengage it, the vacuum is exhausted but a buzzer will sound until the diff lock disengages and it won't disengage if the gears are loaded. Now back to the first lesson! To disengage the diff quickly you can either rock the car gently back and forth but with a bit of practice you can do it "on the hoof". As I said before you can just feather the accelerator so it is just dawdling between power and over-run and it should just drop out.

To summarise;

4.1 - Permanent 4WD with lockable third diff but no limited slip diffs and no traction control. It is possible to get one front and one rear wheel slipping.

4.2 - Permanent 4WD with no third diff as the transfer box picks up on the front diff. Early models have a limited slip diff on the rear axle only but later models (equiped with VSC) have done away with the LSD and rely on the traction control to assist in cross axle wheel spin.

4.3 - Automatic and variable 4WD. No third diff as wind up is controlled by the slip in the drive unit relaxing any load. The vehicle ALWAYS sets off in 4WD BUT if the vehicle is started from rest with the steering turned the drive to the rear axle is significantly reduced. This automatically eliminates "tight corner braking". Cross axle spinning is controlled by the traction control. On all models above XT3, the drive system, steering, ABS, traction control and VSC are all linked and will work in unison (Toyota Active Control).

General - We have to remember that these are "soft roaders" and real off road capabilities are not comparable to vehicles with a low box and lockable diffs (in each axle) and lockabled third diffs. However, they generally provide much better fuel consumption and comfort and have gearing to allow high cruising speed. They also have very acceptable dynamics and will handle in some cases better than a saloon car.

In all cases we have to remember our old cleche - all the electronics in the world won't allow you to defy the laws of physics.

[igormus]

Recently I called at RRG Stockport, which shares its very steep entrance with an adjacent LR dealer, + I kid you not, a Range Rover sport was struggling up the icy slope which my rav barely noticed + I have yet to use the diff lock..so lets hear it for our little Rav's.. Stew

For all those RR Sport owners...who may look in with envy here......

Go Buy a RAV4.......

Here's the proof....

yeah,good ol rav4's...small, reliable, versatile,comfy and economical 4x4.....well pleased

yes as confirmation to this quote - today was a snowy day and i have done city drive as usual daily. what can i say -- i ve found good perfomance of rav on winter tyres and on icy hill roads. it is understood i used 4x4 mode only to take the drive over.

cheers/Igor