1990 Range Rover Classic 3.9 V8 diff lock

also, one thing I have remembered, on occasion when I really got it stuck, I seem to remember that it wouldnt spin or rev. It just sat there and slightly moved

lowranger said:

As a rough test Jack up the offside back wheel on sturdy trolley jack so that you can see it out the drivers window. Start it up and very gently try to drive off. If the lifted wheel just spins and you dont start to move off the diff is knackered. If you move forward this will show that drive is being split to the front wheels and diff is working.

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so it needs to be on the passenger side 2 wheels for this test? Hopefully I wont shoot off down the drive

out with Suzuki in with disco said:

also, one thing I have remembered, on occasion when I really got it stuck, I seem to remember that it wouldnt spin or rev. It just sat there and slightly moved

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thats a concern.If yer stuck that mahossive v8 will spin the wheels with least resistance, the others wont move.Sounds like youve got some big problems.

out with Suzuki in with disco said:

so it needs to be on the passenger side 2 wheels for this test? Hopefully I wont shoot off down the drive

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It doesnt matter which side you jack up, its easier if you are on your own to do the side you can see. You only need to lift one wheel off the ground for the test if it doesn't move the vicous diff is shot. It doesn't matter if its in high or low range but i'd always do it low box as its more controlled.
if you lifted 2 wheels on both front and rear wheels that wouldn't help you, you need to keep one axle on the ground to simulate the conditions of losing traction. Does that make sense?

thanks mate, I will give it a try and see what happens on sunday

right then lads. It seems that I have just jacked it up and although we lifted the 2 drivers wheels off the road and they both span slowly without the car moving, does that mean its knackered? I have just re read the thread and you suggested lifting on one of the wheels. Do I need to go and test it again?

Also, is it possible it hasn't got a diff lock? I have looked at the haynes manual and it makes reference to the diff lock light on the dash or depending on model a lamp on the radio console area?

You should only lift one wheel off the ground. Lifting one on each axle will not tell you anything. If the VC is knackered the car wont go anywhere and will just sit there with the jacked wheel spinning merrily. If it is fine then the car will start to move almost immediately as the VC locks up so do it carefully and be ready to stop otherwise you'll damage the jack/car/someone.

out with Suzuki in with disco said:

right then lads. It seems that I have just jacked it up and although we lifted the 2 drivers wheels off the road and they both span slowly without the car moving, does that mean its knackered? I have just re read the thread and you suggested lifting on one of the wheels. Do I need to go and test it again?

Also, is it possible it hasn't got a diff lock? I have looked at the haynes manual and it makes reference to the diff lock light on the dash or depending on model a lamp on the radio console area?

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So youve got no drive to the rear wheels?Thats is a problem.:doh::doh:

also it will either have diff lock or VC, the age of yours suggests VC.The low range selctor knob has no sideways move ment then its a vc

i can confirm that all wheels drive as I have seen them spining and kicking up mud when stuck. Both the front right and rear right side wheels were spinning when I jacked it up earlier. I will try again with just one wheel lifted and see what happens. What a nightmare.

Thank you to all for your patience on this. I know an imbecile who is useless like me must be a pain in the arse to you guys who know what you are talking about

The 3.9 classic came with a viscous coupling unit...no diff lock. To test lift one front wheel and just put firts gear...if the unit is ok the car sholud move. the viscous unit is on the output to the front axle...is the same as the worg warner tranmsfer box fitted to my ranre rover p38.
I and a friend have mounted an lt230 perfectly into a 3.9 classic.....it goes perfect...and you can use the same lever just addapt it......That goes really well with the diff lock!
hope I´ve help!!
Adal

so lads, if it is the viscous coupling unit, is that a big job? Any idea of how long and how much it would take to fix?

you can get a good second hand unit off fleabay for about 100 quid. takes about 40 minutes to do if you got good socket set and know how to use it.

Can it be changed without removing the transfer box then?

call me simple but I have had a look in tthe Haynes manual. No reference to it. I have looked on ebay for the part and although it refers to diffs' and splines' I hav e no iodea what I need.

Any guidance for a simpleton would be much appreciated, I want to get out there and use the truck!

Incidentally, I wanted to ask about how many miles I should get out of a tank. I put in £85 and its on 185 miles and the light has just started coming on. My mate borrowed it to tow something and put a bit more in so I think it would. have done 200m on a tank.

Is that right? I thought I saw on a thread in here that it should be about 300. I knew it would drink it but no 200m worth for that money!?

fett said:

Can it be changed without removing the transfer box then?

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yes mate, piece of ****. easier on a ramp with air tools, but a bit more awkward laying on the deck, but sure a man of your talent could do it. hardest thing is refilling the transfer box

Oh ok I will bear that in mind si, although I hope it never breaks!

Fuel wise yes that is about right , I was getting only 163 miles form 14 gallons when I bought mine , with a bit of fettling it is now between 200 and 230 depending on the type of driving and how long I let the light stay on before I fill up.

The earlier metal tanks like mine (1990) are smaller than the later plastic one I am told.
They are thirsty, the worst I have driven including the modern yank stuff!

back to original thread

drain the oil from transfer box. undo the propshaft at gearbox end, undo the the big nut holding the flange and withdraw. place jack with piece of wood under box to take the weight, and undo the gearbox mounting from chassis and box lower jack and remove, then undo the bolts around the casing of the viscous, tap and remove, refit with high temp sealant and refitting is the reverse of removal, refill transfer box with atf.

as for the fuel, i get about 200 for 80 quids worth. the joy of a V8

fett said:

oh ok i will bear that in mind si, although i hope it never breaks!

Fuel wise yes that is about right , i was getting only 163 miles form 14 gallons when i bought mine , with a bit of fettling it is now between 200 and 230 depending on the type of driving and how long i let the light stay on before i fill up.

The earlier metal tanks like mine (1990) are smaller than the later plastic one i am told.
They are thirsty, the worst i have driven including the modern yank stuff!

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wheel spinning with fork trucks might be the start of it though PMSL

:violent::focus: A nice pic of me and you si lol.

You not on lpg then?