Excessive play in transfer box KZJ90

[Sag]

Well Shayne at least you've hopefully found the problem buddy,my mrs says I can have the suspension in a few weeks just need the finger straightening now so I can fit em,vice won't do it makes me want to pass out lol

 

[Shayne]

Nice one Shaun just remembered i seen your post asking me about the lights i was about to answer got distracted then forgot all about it . Don't worry mate i will post a pic when i get them fitted truth is i opened the box to see what was in it then put it in the corner of the kitchen where its sat ever since .

 

[Shayne]

New suspension didn't cure the gear change noise but is has sort of muted it to a tolerable level . 1st gear to 2nd is the worst , I think she will just have to live with it for a while and we will see how things progress the rear bushes need changing even if i cant find any play in them so you never know .

 

[Shayne]

Another one http://www.forum4x4.org/threads/50360-Reportage-Différentiel-central-KDJ90?

 

[BobMurphy]

One for Bob Murphy i reckon - My diagnosis without having a clue how the transfer box works is that the chain is slack ???

Shane,

How did you get on with this problem ??

At the time I didn't believe that the 'Hi-Vo' chain could be loose - I'm older and wiser now and recently had to replace one for a TLOC member after his started jumping teeth when off-roading.

Your initial diagnosis could be right .

I'll be interested in following this up.

Living and learning .

Bob.

 

[Shayne]

Nothing to report i'm ashamed to say Bob feels like i've been living under water for half a year and i don't care if the wheels fall off any more i need my shed built .

Somebody had clutch problems (80 series) bought from amayama , not fitted right , clutch release bearing . And the symptoms seemed very similar so i need to (at some point) eliminate one possibility before looking at the other and because i don't know what i'm doing i am guessing that checking the chain is the easiest option .

Would i be right in thinking all i need to do is order a gasket , drop the prop shaft and remove the casing to see the chain ?

 

[BobMurphy]

Would i be right in thinking all i need to do is order a gasket , drop the prop shaft and remove the casing to see the chain ?

Shayne,

No gasket needed, the cases are sealed with silicone/RTV.

Drop the rear prop at the Transfer Box.

Unstake the nut and remove the rear axle Companion Flange (nut can be VERY tight).

Remove the alloy extension that carries the speedometer drive (five 12mm-headed sets).

You can then see the chain in the small cutout where it passes over the drive sprocket. This picture shows the box on its side but you can see the cutout to the left of the output shaft:

Use a screwdriver to try to lift the chain off the sprocket - if you can get it half way up a tooth its probably worn. The teeth aren't very pronounced - not like a bicycle or motorcycle sprocket.

If you remove the large rear cover the output shaft flops and makes it difficult to check the chain, you really need both shafts supported by their bearings.

When removing the speedometer drive cover be careful - there is a very small ball bearing recessed into the shaft that drives the Speedo worm gear. Don't lose it !

The chain I replaced was actually skipping under load, I assume yours isn't doing that ??

There is no adjustment on the chain.

Keep us posted.

Bob.

 

[Shayne]

Thank's Bob that shouldn't present any problems . While thinking about the not ideal window to view the chain and how to get some movement it struck me that if i jack the back wheels off the ground in gear with the centre diff locked and front wheels grounded . Rotational play at the rear wheels should reveal slack in the chain .

What do you think ?

Of course there will be some play as ujs and props bite but i'm thinking a slack chain would allow an inch either way , or am i barking up the wrong tree ?

 

[BobMurphy]

While thinking about the not ideal window to view the chain and how to get some movement it struck me that if i jack the back wheels off the ground in gear with the centre diff locked and front wheels grounded . Rotational play at the rear wheels should reveal slack in the chain .

What do you think ?

Shayne,

All you need to do is . . .

Put the Transfer Lever into 'HL',

Chock the wheels on one side.

raise the wheels on the other side.

Handbrake off.

Grasp the front and rear Companion flanges on the Transfer Box and see how much play there is between them.

Play will either be slack in the chain or wear in the Centre Diff Planet Carrier bearings .

Slack in the UJs and axles doesn't feature here (though they should be free-running).

No dismantling required .

(There will be some slack, even if everything is new, the question is - "how much is bad?" - I can't answer that definitely).

Bob.

 

[Shayne]

OK , one side as apposed to front/rear yeah .

I figure there has to be significant play to cause the bang , its hard to explain but its like a millisecond delay from clutch release to everything locking under load . But its a muted perhaps cushioned bang not sharp like metal to metal .

The truck drives perfectly otherwise and it has been used 20 miles daily since this thread was started without change , surely a buggered bearing would have given up the ghost by now .

I managed a few hours with a pressure washer today before it went dark washing all the green slime out of the yard and i have 5 litres of industrial bleach to finish the job in tomorrows rain so i am at least making some progress towards the jobs i want to do .

 

[StarCruiser]

Sounds to me Shayne like the take up springs on the clutch plate have slack in them or dropped out. Don't know if this is possible on your truck but I have seen clutch plates where the centre rotates a bit before the plate outer.

Does it do it in 4wd or both 4wd and 2wd (sorry, don't know the setup as far as 4wd goes on your truck).

 

[Shayne]

Permanent 4x4 Rich with the option to lock centre diff in high or low box iirc locked or not makes no odds it still bangs . I will do Bobs test tomorrow and take it from there .

 

[StarCruiser]

I would expect the thing to bang when you get wind up from front to back with the CDL locked but not on a straight bit of Tarmac. I would expect the bangs to be during driving but a problem with the clutch plate take up springs to be mostly at take off and deceleration/overrun. The chain could do this I suppose but unlikely if locked and running straight on Tarmac with all wheels the same diameter. I would expect the chain to be under tension when unlocked.

 

[Shayne]

Chain might be a smidgen loose do you think

View attachment trim.985C0307-8E46-4C86-8E49-8FA5629DB1B1.MOV

 

[IRLGW]

Just saw this and think it is the result of a broken pin inside the transfer box. A good few years ago we had a very nice colorado import but didn't realise that it was permanent 4wd so when we were towing big trailers we used to hit the button on the dash ( Yes the CDL) because it seemingly towed much better even at 60mph,,,,,,, two transfer box rebuilds later we were educated as to what the problem was. Now I'm not entirely sure of the exact part but I remember having to strip the exchange box back down because we had an auto box and the selectors where different lengths. I am sorry that I cannot be more specific but I think there is a type of shear pin in there that goes to save the rest of the box. Symptoms sound identical I would think the box is going to have to come out and be repaired or replaced. It can be fixed in one day if I remember correctly. I am surprised this is not more widely documented because Im sure there are a lot of city slicker driving around in these without knowing how the 4wd system operates.

Just an after thought but if you put the transfer box into neutral and put the gearbox into drive is the noise still there?

That was before I did this to it....

 

[Shayne]

Jeez man you could have just jacked it up to have a look at the box was it really necessary to put it on its roof for a look

Thanks for the shout i will bet Bob has a pic of this shear pin ?

 

[Shayne]

Just an after thought but if you put the transfer box into neutral and put the gearbox into drive is the noise still there?

Tried this and no noise at all on releasing the clutch even at 2500 rpm .

 

[BobMurphy]

Thanks for the shout i will bet Bob has a pic of this shear pin ?

There isn't a Shear Pin in a '90' Transfer Box - and there isn't a CDL Switch on the dash either. On the '90' we engage the CDL with a lever - the rear diff locker is electric (and only works when the Transfer Box is in 'LL').

It sounds as if IRGLW is talking about a later model as my '100' has an electrically-operated CDL and the Transfer Box is quite different to that on a '90'. I suspect a '120' is similar to the '100' but I'm guessing.

There are three differences between '90' Transfer Boxes on a Manual and An Auto:

The 'Auto' has longer Selector Shafts as the Transfer Lever is mounted on an extension housing between the Gearbox and the Transfer Box (the protruding shafts can rust and bind).

The manual has Synchromesh on the High Ratio gear pinion, the auto doesn't. You can change from Low into High on the fly in a manual (5mph or less) but an Auto has to be in Neutral before you do that.

There is an additional Detector Switch on the Transfer Box on an Auto. It tells the ECU that you are in Low Ratio (the other one lets the Rear Diff Locker work). I think the Auto has a different throttle response/gear change point in Low .

No Shear Pins - unless you count the rather weak Centre Diff Planet Carrier (but at £400+ its a costly safety feature).

There is, However, a sprung-loaded 'Overload Protection' plunger that ordinarily prevents the 'High-Low' Epicyclic Gear's Anulus from rotating. If you are doing some extreme off-roading in Low Ratio this thing will allow the outer drum (annulus) to rotate, thus relieving the stress from the Planet Carrier and Sun Wheel.

Not many people know that (though I have explained it before) .

So if you are in a tight spot trying to climb a rock face and you get a sudden 'Machine Gun' noise - its Mr T protecting your Transfer Box .


The sprung Plunger can be seen at the front of the picture, it engages with the webs on the outside of the High/Low 'Anulus' (behind, with its retaining ring).

I dunno, Shayne. I doubt all that slack between the rear and front axles is attributable to the chain. What is the Transfer Box like if you just turn the output Companion Flanges with the Centre Diff locked ??

Diagnosis by Internet is notoriously unreliable .

Bob.

 

[Shayne]

I have only remembered now that diff light was flashing when i put it in HL then the phone went and i didn't look at the dash again before making the vid and putting everything away

Seems fair to accept the problem (whatever it is) relates to the t-box though so i can forget the clutch .

 

[IRLGW]

It was a long time since I drove the colorado but it was a an auto import. However maybe it was either a button on the center console or maybe it was just by flicking the transfer lever over. I cannot actually remember except that we drove it in 4wd when we shouldn't have. Could have been the sprung plunger but it sounds like exactly the same problem. Quickest job is to get a second hand transfer box and put it in. Then strip down the old one and educate us all as to the problem!

By the way collies don't corner very well but do have an excellent crash rating....