1995 Rav4 Possible Diff Clunk?

[rav4kay]

Ok, I will try an oil change first but I just need to know what oil to use. Can anybody help?

[gjnorthall]

Already detailed in my post on previous page - 75W90 GL5 gear oil

[rav4kay]

Already detailed in my post on previous page - 75W90 GL5 gear oil

Thank you

[rav4kay]

Have just tried taking the vaccum pipe off, made no difference :(

[gjnorthall]

Then it's unlikely to be the diff-lock being activated randomly. How sure are you that the diff-lock is engaging and disengaging - how did you conclude this? Have you had a look at the transfer box - any sign of it being damaged or interfered with. Looking at the drawing of the mechanism on the transfer box, I'd be pretty sure that actuator arm wouldn't move of it's own volition - it would need the vacuum diaphragm to move it.

[rav4kay]

Well I dont know for certain, just guessing as thats what it sounds like. It will sometimes do it when the car changes gear.

[gjnorthall]

Nothing really new to add but recounting so far..........

- The clunk from the rear has been identified so the concern is the clunk from the front.

- Clunk occurs when moving slowly on lock and when driving along (though I'm not really clear about the latter)

- Clunk improves with distance driven.

- Jacking the car up and engaging D and R indicates that front and rear diffs are operating as they should.

- Disabling the diff lock by disconnecting the vacuum supply doesn't improve the clunk. Unlikely that the diff lock is engaging and releasing arbitrarily.

It's really difficult to take things further without actually experiencing the problem and it may be a case of going through things systematically with a fine tooth-comb .......................Start by checking the outer and inner front CV joints for free motion and roughness......... Check gearbox, diff etc mountings. ..................................

Don't know where in Flintshire you are but there's a couple of good 4x4 garages in North East Wales - one just outside St Asaph who may be able to proffer an opinion.

[rav4kay]

Would a transfer box off a manual fit an auto? Im struggling to find any auto spares.

[gjnorthall]

The transfer box function is different between the auto and manual versions - the Toyota literature describes the manual transfer box as having a centre mechanical diff lock and the auto as having a hydraulic centre diff clutch. Might be worth checking with Toyota that the part numbers are different - but I strongly suspect that they're not interchangeable. It's a tall order finding a scrap auto Rav of this era - have you tried 247 spares and Parts Gateway - Furbers had loads of older Ravs in stock when I was looking for a 4.1 gearbox for someone a while back?

[rav4kay]

Ok thank you. I will try them now.

[rav4kay]

Just out of curiosity, if someone put a rear diff from a manual car onto an auto, what effects would that have?

[gjnorthall]

I'd guess that it's the same rear diff on the auto and manual car - it's nothing really to do with the rest of the transmission, so no reason why the two should be different. (presuming you do mean rear diff not front diff)

[rav4kay]

Yes the rear, my car is in a garage at mo having rear arm changed and one of the mechanics suggests the diffs are out of sync so thinks the rear is the wrong one. Do you know what the part code is meant to be?

[gjnorthall]

Diffs out of sync - I'd like to hear the explanation for that one! The front and rear diffs are connected since this is a permanent 4WD vehicle. If a diff, say, with the wrong ratio was fitted to the rear - the car would be un-driveable and something would break very quickly. Depending if the ratio was too high or too low - the rear wheels would be forced to turn faster or slower than the fronts. (it's sort of the same reason that this model mustn't be MOT brake tested on front rollers only). You've mentioned previously that the issue seems intermittent and improves with distance driven - any issues with the wrong rear diff fitted etc wouldn't be intermittent.

[rav4kay]

Right, gear oil done, all bushes snd mounts including engine mounts, prop bushes/ mount all been changed.

So could only be rear diff, front diff or transfer box. Just dont know which ones to spend money on if its not that one thats causing the problem.

[gjnorthall]

Did you bottom out the clunk issue?

[rav4kay]

Yes, unplugged the sensor from the diff lol

[gjnorthall]

Excellent - wonder why disconnecting the vacuum didn't work.

[rav4kay]

No idea, I'm just happy now there's no clunk when im driving.

On the look out for some side steps now.

[gjnorthall]

IMHO I think that side bars look much better than a step on the 4.1 - unless of course you want a step for functional purposes. Something like......

http://www.autostylinguk.co.uk/products/ProductDetail/Side-Bars-63mm-Stainless-Mach-for-Toyota-Rav4-Mk1-(94-98)-3-Door/SC4X4/PG/GCTORA1/PC3CS18TORA1S/PRvehicle/FB/FP.html

Steps / bars from the 4.2 3 door should fit with not too much difficulty and are probably easier to find - some aftermarket units are advertised for 4.1 / 4.2

[rav4kay]

Yeh I like those bars But didnt really want to pay that much lol. Second hand would probably be best.