discovery transfer box

[44jetboat]

after a great trip to lake daniels with the 4wd club drove the discovery home and noticed it felt a bit strange.

after some driving it seemed like the center diff was still in, light was off tho.

checked linkage and connection on transfer box and all seems to work. linkage works and turns the mec on the transferbox

but when lifting up one wheel and having the lever for diff lock off, both axles are turning. so the center diff is not disengageing.

have i buggered my center diff?? if so how?? it was fine on drive up was in center diff lock for 2 days soild. in saying that truck has over 330000ks on it now.

worth removing and trying to fix or eaiser to replace with another......

oh also are they the same from v8 to diesel manual to auto?? cheers

[Alister]

My understanding on this is somewhat limited, but as you haven't had any other answers I'll have a go.
What I understand and, from my experience with my D1, is that the transfer box can need to be what is called "unwound" to get the centre diff-lock to disengage and the light to go out.
As far as I'm aware the way to do this is to put the vehicle into reverse and drive backwards for a bit - then engage drive/1st and go forwards and see if it comes right. If it fails try again, possible with the diff-lock engaged during the reverse, then go forwards with it unlocked etc.
Heaps of info on Google too.

HTH,

Alister.

[L-andy]

The good news is that the switch for the light is activated directly by the movement of locking dog in the transfer box (not the position of the lever), so it indicates the actual status of the diff lock (unless bulb is blown or wire has fallen off the switch etc). The switch is in the top near where the spindle for the diff lock enters. It is threaded longer than is needed with a locknut to set adjustment. NB, screwing it in too far can jam the movement of the locking dog.

So....if lamp/wiring/switch are electrically ok and it says the diff lock is off, its off! There is a plate on the side of the front output cover which can be removed to check movement of the dog but its a bit fiddly and usually very reliable.

The bad news is (although I have never seen it) is a broken cross pin in the diff can apparently cause it to bind up just like the diff is locked.

It is also possible to remove the whole front output cover of the transfer case and split the center diff etc without removing the output drive flanges. It may even be possible not even removing the transfer box but I imagine this would be very fiddly on a disco (tight enough on a Defender)

AFAIK all Disco and most Rangie LT230 transfer cases are the same ratio (1.2:1) and are interchangeable. They have some variations in bearing types R or T (for roller or taper) and Q for quiet helically cut gears (Q apparently weaker) but all physically fit. Some early Rangie ones are 1:1 but Defender LT230's are mostly 1.4:1 some are 1.2:1 and a few early diesel ones are 1.6:1

Andy

[44jetboat]

thanks guys. will be pulling out this weekend. looks like broken the spider gear shaft. bit gutted but hoping not too much of a fix. kam do a stronger shaft for the spider gears so might be worth a look . but then only running 32s with front and rear lockers.

will up date when i pull out.

oh and if anyone has a spare transfer box. flick me a pm

[44jetboat]

yep the center diff died.

havnt pulled the old transfer box apart. but i would say the spider gear shafts have broken. heaps of metal fileings.

all fixed now.

cheers for the help.