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Hey everyone,

Just bought a beautiful 01' RAV4. It's got 110xxx kms & has been at the dealer every 8K since new.

This is my first Toyota & first 4wd.

I'd like to find an aftermarket part that disables the 4wd, ideally electronically. Some sort of drive shaft u-joint switch or something.

Has anyone ever seen anything like this or know of other ways to do this?

We'll be doing a lot of highway & around town & I don't see the need to be turning the transfer case & rear diff & associated drive shafts if I don't need to all the time.
 

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Seems like a lot of trouble and expense to save maybe 1 Mpg.
Might be cheaper to trade in for a 2WD model.
I had a Jeep with locking hubs for that purpose, but then the front drive shaft U-joints dried out because of lack of use.


Ott
 

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You'd have to physically remove at least a section of the driveshaft AND the rear halfshafts to keep the rear differential from turning. To hold the rear hubs on you'd have to take the outer CV joints apart and remove the shaft itself.
 

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Removing the driving shaft will not make the RAV4 2wd.... it will not move at all. Without welding the center-diff, It would only be possible with a manual RAV4.1 with lock. Like someone else said: buy a 2wd.
 

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I'm VERY familiar with the 4.3 RAV4's 4WD system since I have one but not so much with the 4.2 so I tried to find a diagram of it online. One statement I found said it has a viscous coupling center differential. IMO that's a misnomer with these names being tossed around by the uninformed.

Many AWD cars have a viscous coupling (one input, one output) in their driveshaft to avoid "crabbing" when cornering. It's a simple and lightweight solution that works well as long as the coupling lasts. If it does wear out or if the driveshaft is removed the vehicle simply reverts to FWD. The 4.3 RAV4s have a similar system but with the viscous coupling replaced with an electro-coupling mounted on the input if the rear differential.

Other vehicles actually do have a center differential (one input, two outputs). In that case it would have to be the first differential after the transmission with it's two outputs going to the front and rear differentials respectively. But unless it had some limited slip mechanism built in (which wouldn't be called a viscous coupling) it wouldn't be very effective since it would allow one spinning wheel to stop the vehicle, as would removing any one of the drive or axle shafts. It could have an electrical lock but then the crabbing problem isn't solved.

So I'm not for sure what the 4.1 & 4.2 RAV4s have and would like to see some accurate diagrams but if they refer to a "viscous coupling center differential" I'll know they can't be correct.
 

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This is what the diff looks like in a manual RAV4.1-2 (auto transmission only have one diff like a 2WD). There is 2 different differentials inside the same case, and both have 4 pinions gears. The pinions at left splits power between front wheels (front diff). The right diff is the central diff, that splits power between front and rear differentials via the viscous transfer case. The main difference with the 4.1, is that a lock mechanisn cancel the viscous.... locking front and rear differentials together.


 
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Appreciate the diagram Commando. So what's the power flow in terms of the outside gear on the left, the splined shaft on the upper right, and the pinon shaft on the lower right?
 

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I'm not sure what you're asking. The outside gear on the left is the left front wheel, the splined shaft on the right is the right front wheel, and the pinion shaft on the lower right is the transfer case output to the rear diff.


Maybe this can help understand the power flow:


 

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Okay, got it. And it is as I thought and all makes sense now. What I meant by the "outside gear on the left" was the large diameter one which as I surmised is the power input from the transmission. So the multi-plate clutch is what some refer to as a viscous coupling. I've always pictured a viscous coupling to be a "lump" in the rear driveshaft. That must be what the automatic 4WD version has.
So you end up with lots of "extra" gears and their associated loss in the manual transmission models such as the OP's.

It means the only way for the OP to gain virtually any benefit would be to replace everything after the engine with FWD components.
 

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Super link! Pretty pictures and good descriptions.
So it turns out neither the 4.1 or 4.2 automatics or manuals have dumb viscous clutches at the center differential or anywhere else. Rather they have variable engagement multi-plate hydraulic clutches very similar to those in automatic transmissions complete with logic operated valve bodies. Pretty sophisticated - until the 4.3 system was developed eliminating the need for a center differential. Effectively Toyota took the hydraulic clutch out of the center differential, made it electro-mechanical and moved it to the rear differential.
 

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In reality, the manual 4.2 don't have multiplate clutches in the transfer case like the picture I posted before.... It really have a dumb viscous like you say. I just did not find any picture of it.


I will try to open my 4.1 and 4.2 transfer cases to see what they really are.
 

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I wanted to edit wrong/inaccurate information on a precedent post, but it's impossible. :(


The pic I posted two days ago on the 1st page (transmission front and center diff, with multi-clutches t-case), represents some manual All Trac vehicles: Celica, Camry, Corolla, Previa and Caldina... NOT RAV4!





The front and center diff in the same case (inside the transmission) is identical to manual RAV4.1 and 4.2.


I opened my RAV4.1 transfer case today, and there is no clutches or viscous. It's a one piece ring gear mounting case assembly.


I took a look at work on Mitchell's , and found Toyota transfer case exploded views!


RAV4.1 transfer case:








In the next picture, we can see the 4.2 really seems to have a viscous coupling transfer case:





 
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