Diff lock non function

Being as though it's been 4 months since discovering my diff lock don't engage(3.9 V8 Disco M reg), decided to have a proper look at it today. Excuse the vauge description below.......

Took the centre consol out and finally got to the little gear lever gubbins.

The actual diff lock it's self works ok. Took pin out of connecting arm and moved it by hand ok. The bit thats stuck in is the steel pin that runs left to right (assuming it should). Tried all sorts of tricks to free it off,

Penetrating oil WD40 GT85 Small hammer Bigger hammer Pry bar Swearing

So i plan to leave it a bit to let all the oils soak in. If i have no luck with it, how easy is it to change/strip down and rebuild??. Looking at it i doubt it's been used from new.

Dom J

Reply to
Dom J
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I hope that you have not embarked on an unnecessary wild goose chase.

When you say that the diff lock does not engage exactly what do you mean?

You then go on to say that "the actual diff lock itself works ok".

I have a nasty feeling that you may be expecting certain things to happen immediately and they do not. That could be by design.

Could you expand a little on what your original complaint was and what has led you to start investigating the linkage?

Reply to
Dougal

No problem Dougal,

First became aware of a problem at the unoffcial at the start of the year. Tried to pull someone out of a bog and went to enagage diff lock. Tried to push lever over to left and it was solid. Martyn(mother) had a go as well and couldn't move it. At this point i should point out that the car was an ex disabled persons car and i doubt that high/low and diff lock had ever been used. High/low ratio was stiff to start with but since i've used it it seems ok. Most people i have spoken to about this have said "just give the lever a good thump and that should free it off". Tried this to no avail. Apparently they do this all the time because the shaft seizes in the housing due to lack of use. Sort of forgot about it until yesterday.

Have just had another and go. This time i took the whole high/low lever assembly off the top of the transfer box. The lever which connects to this asembly and runs down to the diff moves ok by hand in and out no problem. To me this indicates that the assembly now sat on the bench is at fault. It works forward and back (ie High and Low) but will not move at all left and right (Diff lock in/out). Hope this answers your questions Dougal.

I'm going to try and find a car like mine in the breakers to have a look and see exactly what should happen.

Dom J

Reply to
Dom J

Have you tried giving the beggar a soak overnight in diesel it penetrates very nicely into seized joints. Derek

Reply to
Derek

Sorry to put you through that Dom but I wanted to make sure that we weren't about to bark up the wrong tree - "I moved the lever but the light won't go on/off etc.".

OK - the lever wouldn't move which you've rightly concluded is likely to be due to lack of use.

I'm still very confused by what you're telling us so I'm going to drag it out of you!

You now have a 'working' high/low setup by which I presume the lever moves backwards and forwards H-N-L (before you disconnected the linkage etc.). Have you actually driven with high/low gears to verify that they are engaging or are we only talking about movement of the gear lever?

I don't understand what you have on the bench. Is this the high/low selector shaft assembly? The housing in which the selector shaft moves fits on the top of the front output shaft housing, has its long length across the vehicle and is held down with six bolts. The selector shaft will rotate in its housing only. It does not pull in/out.

If you actually have functioning high/low you don't need to be looking at this part - it's working. This part also has nothing whatsoever to do with the diff lock.

I'll let you respond to that then we'll move on.

Reply to
Dougal

Dougal uttered summat worrerz funny about:

On My Disco that same lever moves sideways to eng the Diff lock with H-N-L

Lee

Reply to
Lee_D

At this stage I'm at the far end of the linkage - the shaft that's actually part of the transfer box.

That's why I'm keen to see what Dom has on his bench - linkage or high/low selector housing.

The linkages that you expect to see do 'intertwine' as you say but I'm beginning to think that what is there may not be what we expect to see.

Reply to
Dougal

Dougal uttered summat worrerz funny about:

Gotcha

:-)

Lee D

Reply to
Lee_D

Right here we go.....

Derek, yep i've tried soaking with all sorts of oils and it still wont budge. Put it back on the car as i need to use it soon.

Quote from Dougal:

"You now have a 'working' high/low setup by which I presume the lever moves backwards and forwards H-N-L (before you disconnected the linkage etc.). Have you actually driven with high/low gears to verify that they are engaging or are we only talking about movement of the gear lever?"

Yes the H-N-L bit works ok. Have driven with it in L and all is well.

Dougal again:

"I don't understand what you have on the bench. Is this the high/low selector shaft assembly? The housing in which the selector shaft moves fits on the top of the front output shaft housing, has its long length across the vehicle and is held down with six bolts. The selector shaft will rotate in its housing only. It does not pull in/out."

I think i know what bit you are on about and no it aint this bit that was on my bench. All of what you describe above seems to move freely enough. As Lee said "On My Disco that same lever moves sideways to eng the Diff lock with H-N-L". What i had on my bench was the actual lever assembly that sits on top of the transfer box. Its held down with 4 M8 bolts. Consists of a ali housing, a shaft that runs left to right (=A354 new, apparently!!!), in this shaft is a ball joint that takes the actual gear lever bit. Attahced to the bottom of the lever shaft is a spline thingy which does the H-N-L bit. The problem bit is the bearing assembly at the passenger side of the ali housing. The left to right shaft runs in this and allows the lever to move to the left to engage diff lock. This bearing thingy is seized solid to the shaft, hence no movement left to right.

Anyone understand that?!. Oh nearly forgot the new bearing bit is =A315.

Dom J

Reply to
Dom J

I've found a picture to remind what's there and now understand what's on your bench.

This 'bearing thingy' is attached to the ali housing with two countersunk screws in a pear-shaped flange?

The 'bearing thingy' (I like these technical terms!) looks as though it's a parallel bore in which the cross-shaft runs and will have an internal groove for the o-ring which seals between the two.

I think that you should be able to get this moving again without any expense other than o-rings and gaskets. At worst case you want to dismantle the entire group until you have the cross-shaft and the 'bearing thingy' in your hands and can attack it with greater violence and heat.

As a first step I'd support the assembly with the passenger end and 'bearing thingy' uppermost and liberally apply diesel etc. at the end of the cross-shaft. Leave overnight.

Then try to tap the cross-shaft torwards the main housing (diff lock apply direction). Once you get some movement, knock backwards and forwards with lubrication until free. Don't stop there - remove the 'bearing thingy' and clean up thoroughly, replace o-rings etc..

Do you have an exploded view of the bits? I can send some pictures if your e-mail address is valid.

Reply to
Dougal

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