Transfer case

[david7307]

Just had my Disco at the mechanics and thy say the transfer case is getting bad, a lot of slack in it, my question is do i get it fixed or start looking for a good second hand one , I have not asked what the cost of doing it up will cost,
When i changed the oil 10th ago it was clean no metal filings in it or none that i could see
and if i replace it where do i start looking , any info will be great ,

[Pedro_The_Swift]

how long are you keeping the car? will answer the question...

[bee utey]

A good used transfer case would be loads cheaper than a rebuild. Once your old one is out there's no rush to find out what's wrong with yours. It could just be the centre diff needing shims. An Ashcroft ATB might be indicated as a useful upgrade if you're intending to keep the car.

[Jazzman]

I've got 2X LT230's. A rebuilt 1.4 and a 1.2 with new centre diff dome washers. PM me if you would like more info.

[trout1105]

The trouble with getting a used/second hand transfer box is that you don't know for certain that it is 100% Good to Go, With a rebuild you "Know" that the box will go the distance and will be Fit for purpose.
A second hand box will undoubtedly be the cheapest option But a rebuild is the Better albeit more expensive option [thumbsupbig]

[jonesfam]

Reconditioned?
Warrantee & you know it's been redone.
Just a thought.
Jonesfam

[workingonit]

Before you took it to the mechanics did you feel there were any problems - or was it a rego check?

Sometimes it can be like engaging in party conversation with a shrink...trailing off with would you like to make an appointment?...No, I'm fine...No, your not...really!?

[PhilipA]

IMHO transfer case slack would most probably be due to wear in the thrust washers of the centre diff.
The washers are bronze and most of the swarf falls into a "sump" just below the diff. You may not notice the bronze as it is not bright and shiny in the oil.

Does the transfer leak lots of oil from the intermediate shaft ? This is one of the major wear points and if it does would indicate a rebuild.
Does the transfer case make lots of noise changing from power on to power off? If so it could indicate worn bearings allowing the gears to get out of alignment.

It may be worthwhile to remove the nose of the transfer case to see the condition of the thrust washers. This can be done in situ so should not be too expensive.
Regards Philip A

[david7307]

Sorry for being so long to get back been as sick as a dog
climbed underneath yesterday and checked movement in case , its 12oclock to 2oclock , i have no front drive prop shaft on at moment,
under my disco there is oil leaks from front seal none from the back seal

[Jazzman]

Sorry for being so long to get back been as sick as a dog
climbed underneath yesterday and checked movement in case , its 12oclock to 2oclock , i have no front drive prop shaft on at moment,
under my disco there is oil leaks from front seal none from the back seal

The oil leak will be from the felt seal behind the flange most likely, they are easy to replace. 12 to 2 o'clock is a bit of movement but not quite enough to get an idea of how worn. The reason is the front output shaft is not tight where it meshes with the selector folk so it will always move anyway.

A better way to check would be to remove the rear prop shaft from the transfer case flange, turn the rear flange and assess how far it turns before the front begins to turn (the opposite direction). This is not fool proof either but may give a better indication.

Essentially if it has done more than 150,000kms the centre diff dome washers will be worn anyway, so they may as well be done. It is cheaper than rebuilding it and you can replace the felt seals at the same time. Or put a seal kit through it.

But it is worth checking to see if there is any oil leaking from the intermediate shaft, they end without the nut. Because this will change everything as the case is likely worn, but can be fixed. (If you know the right people [bigwhistle]) Check out the sale yard section for a picture of the end of the shaft, there is a transfer case there which has new dome washers fitted.

- LT 230 D2a Transfer Case - West Gippsland, Victoria (https://www.aulro.com/afvb/driveline-parts-for-sale/260533-lt-230-d2a-transfer-case-west-gippsland-victoria.html)

[laslo71]

if you want to keep the car long term then I would rebuild the case instead of buying a used one (can be the same s..t).
2 months ago my transfer case was also off to change all seals, o-rings and during this job I have found not so difficult to even more open and rebuild the unit if needed. All the parts for rebuild cost about 100 GBP from Ashcroft and you can also find good instructions how to do it.
But if your intermediate shaft is leaking and moving a lot without O ring means the casing is worn and need to be sleeved or changed to new one.

[Homestar]

Sorry for being so long to get back been as sick as a dog
climbed underneath yesterday and checked movement in case , its 12oclock to 2oclock , i have no front drive prop shaft on at moment,
under my disco there is oil leaks from front seal none from the back seal

With no front shaft in it’s going to feel worse. How many KM has the vehicle done? When I did some work on mine it had 362,000KM on it and it had never been touched. It had towed a van around Aus 3 times as well but it only needed bearings, seals gaskets and some centre diff work. I did it myself and parts were around $300 all in.

LT230’s always have some slop even when new so unless it’s doing something it shouldn’t or you can’t keep oil up to it I’d just keep going for the time being. I bet there’s heaps out there like your in similar condition still going fine.

Just my 2 cents.

[Pedro_The_Swift]

Must admit Gav,, we dont hear of many TC going bang...

[Homestar]

Yeah, the LT230 is a very strong bit of kit and rarely stops a vehicle outright. They can be worn to buggery but still soldier on without issues for years.

[Bohica]

Who in Melbourne can do this?

[Homestar]

Who in Melbourne can do this?

Which bit needs resleeving?

[laslo71]

If the intermediate shaft O ring does not seal anymore (housing worn) you can repare it by using a steel bush.
You can find more detailed explanation on Ashcroft site.
Ashcroft Transmissions (http://www.ashcroft-transmissions.co.uk/diy-rebuild-kits/lt230-rebuild-kits/lt230-sleeved-casing.html)

[david7307]

With no front shaft in it’s going to feel worse. How many KM has the vehicle done? When I did some work on mine it had 362,000KM on it and it had never been touched. It had towed a van around Aus 3 times as well but it only needed bearings, seals gaskets and some centre diff work. I did it myself and parts were around $300 all in.

LT230’s always have some slop even when new so unless it’s doing something it shouldn’t or you can’t keep oil up to it I’d just keep going for the time being. I bet there’s heaps out there like your in similar condition still going fine.

Just my 2 cents.

thanks my disco has done just over 330000 .i also pull a caravan 18ft , just dont want to be heading along highway and something go bang, but after reading your message i feel better about it, as far as i know it uses no oil when i did last oil change it was still full and that was after 20000

[Homestar]

I would highly doubt it would be the TC that leaves you stranded, there’s plenty of other things that will first IMO

[DazzaTD5]

*Round mid 200K they start to leak.
*Not a issue, just check oil level every now and then.
*A LT230 transfer case is highly unlikely it will ever go bang, unless it runs out of oil.
*Dont get all hung up on the stainless sleeve for the intermediate shaft, myself and others have been rebuilding the LT230 transfer case for years without doing it.

*A typical Discovery 2 transfer case will have say 250K on it, will leak oil, have no centre diff pre-load left and still keep going find. (A Defender TDCi (puma, 2007 - on) transfer case will be exactly the same but have half as much km's on it)

[DeanoH]

As others have said, the LT 230 transfer case is pretty robust but it does have a couple of issues. One is failure of the centre differential side washers adding to slop in the drive train.

For those that may be unfamiliar the LT230 transfer case looks like this.

139059

The centre differential assembly when removed from its housing looks like this

139060

And when pulled apart looks like this

139061

Inside there's a conventional spider gear assembly and two piece cross pin with (bronze?) side/thrust washers. Drive output (front and rear) is via the two (larger) side gears which fit into the differential case with a fibrous thrust washer/shim in between. The fibrous side washers come in differing thicknesses so that correct meshing of the gears can be attained.
When these shim washers wear/disintegrate the result is slop in the centre diff/drive train. The bronze side washers shown in the above pic are new ones.

139049

It is very common to find the side washers worn wafer thin or totally disintegrated when pulling a centre diff down.

139055

This is what the inside of the centre diff housing looks like and in this example the wear is very slight. Replacing the side washers when excessive centre diff slop first becomes apparent is a fairly simple and cheap exercise. The bronze side washers are only a couple of dollars each.

If you leave it too long you can end up with something like this.

139056

This centre diff housing is IMO verging on un serviceable. Not only has the shim washer worn deeply into the housing (before disintegrating) the back surface of the spider gear has also worn deeply into the housing. Whilst it's possible to fit two bronze shim washers here to compensate for the wear I've reservations as to how long they would last, though I've not tried it.

Here's an alternate 'fix' that one member here is trialing. This is the same badly worn centre diff assembly fitted with larger diameter hardened steel shim/side washers between the spider gears and the standard bronze shim/side washers.

139057

This picture also shows pretty well how the spider/side gears mesh together as well as the selectable thickness fibre shim that is chosen to 'set' the correct mesh and thus minimise slop/backlash in the centre diff.

Deano :)

[AK83]

the standard diff pins can go bang!
But they usually just wear out first and cause wind up in normal conditions.

[DeanoH]

Another issue with the LT230 is that the intermediate shaft wears an elongated hole in the TC housing allowing oil to leak out. This can be quite messy as a little bit of TC oil goes a long way and can affect both the aesthetics and resale as the vehicle. Here in Victoria the vehicle could be deemed unroadworthy. I've not seen one where the TC has run dry and failed because of this but with poor maintenance I guess this is possible.

139062

This is the end of the intermediate shaft that can flog an elongated hole in the transfer case. This is a bugger of a thing to fix. The transfer case needs to be removed from the vehicle and totally stripped down before being attached to a milling machine table where the centre of the elongated hole is determined before machining the case to take a stainless steel insert like the one supplied by Ashcroft.

This is what a 'repaired' TC looks like.

139065

With the Ashcroft supplied stainless steel insert fitted the TC housing is better than new. The above photo shows the end of the intermediate shaft sitting about 1cm proud of the housing to show the internal 'o' ring seal. It's a pity Land Rover didn't do a similar thing when this design fault first became apparent :(

Deano :)

[John_D4]

Wow thanks for the write ups Deano. Mine is leaking also & I’m trying to decide whether to just do the seals or crack it open and do a complete rebuild. Apart from the leaks I haven’t noticed any issues. I’m planning on installing the CDL linkage next week tho. I still need to get a good look at it to see exactly where it’s leaking from.

[whitey56]

Answers to a couple of questions please.
Is the wear on the CDL thrusts dependent on the amount of locked 4wd driving or will it still happen with tarmac miles.
With no oil contamination during their life what K's would you expect out of the thrusts with mostly tarmac driving.
When the thrusts are worn to the stage that they need replacing {not buggered} is the play that noticeable on the output flange compared to a good CDL.

Thanks for any replies.

[rick130]

Answers to a couple of questions please.
Is the wear on the CDL thrusts dependent on the amount of locked 4wd driving or will it still happen with tarmac miles.
With no oil contamination during their life what K's would you expect out of the thrusts with mostly tarmac driving.
When the thrusts are worn to the stage that they need replacing {not buggered} is the play that noticeable on the output flange compared to a good CDL.

Thanks for any replies.Not locking the CDL quickly enough is usually what causes the wear.

IMO the best fix for this is an Ashcroft ATB...

It also takes so much backlash out of the t/car it isn't funny.

[ozscott]

The LT230 is definitely a strong bit of kit. At 300,000 I was naughty and took my leaking transfer box on a holiday on the Old Tele Track and went through deep water umpteen dozen times. If oil can get out water can get in. Got back and couldn't find time to check it for 6 months and when I changed all the oils the transfer bad water in it and was noisy. Flushed and changed oil but still noisy. I was lucky and got a box that looked like new from Hong Kong (guy that imported d2's is no longer doing so..) that had 20,000k on it for $300.
Cheers

[DeanoH]

................. Mine is leaking also & I’m trying to decide whether to just do the seals or crack it open and do a complete rebuild. Apart from the leaks I haven’t noticed any issues. I’m planning on installing the CDL linkage next week tho. I still need to get a good look at it to see exactly where it’s leaking from.

If the only issue you have is oil leak(s) I'd suggest nailing the source of this first before considering a rebuild. Your Gerni is your friend here :) Common places to check are the intermediate shaft previously mentioned, bottom cover plate and the also previously mentioned felt seal behind the front output flange. There are other 'opportunities' for oil to escape but these are the main ones to check. With the cover plate it's worth noting that the two bolts closest to the drain plug go through to the inside of the TC, the others are blind. A bit of silicon on the threads of these two bolts and under the heads of all the bolts is sometimes whats needed to seal this area properly. If the TC has been removed previously it is very easy to damage the input seal allowing oil to escape from here.

As to whether the TC needs a re build this depends on how worn it is which depends on how many k's and how hard they've been. My 'rule of thumb' here is if the intermediate shaft isn't flogged and the insides of the centre diff assembly case isn't badly worn I'd consider leaving well alone. The bronze side washers will need replacing if you've pulled it this far apart. Someone mentioned in an earlier post that it may be possible to remove the centre diff 'nose' in vehicle which isn't something I've tried but would save considerable time and effort in a simple centre diff 'overhaul'.

Deano :)

[PhilipA]

Just be aware if you pull the nose and replace the front bearing you should redo the preload on the front bearing, although you would probably get away with the stock shim already there.

That is why if you replace the nose with a locking one like I did, you have to swap the bearing and shim from the nose you removed to the locking nose. Mine seems fine.

BTW Loctite Thread sealant 547? is the stuff I use on the threads of the sump cover. I have fitted a big sump and it is as dry as.

Regards Philip A

[donh54]

Not locking the CDL quickly enough is usually what causes the wear.

IMO the best fix for this is an Ashcroft ATB...

It also takes so much backlash out of the t/car it isn't funny.

So there's a good chance that most of the non-cdl D2's (if they've done much dirt road/sand/offroad) would be in the line-up for a rebuild after 200K or so? (Mine's got 310K on the clock, but doesn't look to have done much off bitumen at all)

[DeanoH]

Answers to a couple of questions please.
Is the wear on the CDL thrusts dependent on the amount of locked 4wd driving or will it still happen with tarmac miles.
With no oil contamination during their life what K's would you expect out of the thrusts with mostly tarmac driving.
When the thrusts are worn to the stage that they need replacing {not buggered} is the play that noticeable on the output flange compared to a good CDL.

Thanks for any replies.

As Rick points out not using the CDL appropriately when 4WD'ing will lead to accelerated wear of the centre diff thrust washers. It's also worth noting that most D2's don't have an operational CDL, only the D2a's.
The centre diff thrust washers are wearing all the time regardless of terrain covered, the amount of wear is determined by km's traveled, and load on the vehicle/centre diff ie towing, acceleration or hard off road work.

Locking the centre diff doesn't remove its slop from the rear drive train.


https://www.aulro.com/afvb/attachments/discovery-2-a/139078d1523674428-transfer-case-centre-diff-lock-operation.jpg


In 'normal' operation the centre diff carrier assembly rotates and delivers drive via the spider gears and side gears to the front and rear drive shafts, just like any other diff. When the CDL is activated the two gears shown are coupled, effectively joining the diff carrier and the front drive shaft together. This stops the front drive side gear(in the centre diff) from rotating which stops the spider gears from rotating and effectively disables the centre differential action. Drive to the rear diff is now fed via the 'locked up' centre diff gears. :) Any 'slop' in this drive path ie. worn side washers is still there.

It doesn't take much to wear the bronze side washers and instill a bit of 'slop' to the drive train eg. my 2002 D2 has done 160k Km only, never towed or been off road or even used low range, it's been a 'shopping trolley' all its life and it has slop in the centre diff, not much, but it's there.

Comparing the slop between a 'good' TC and a worn TC is quite easy if you have CDL and a good one to compare it to :). What I do is activate the CDL and see how much I can rotate one drive shaft with the other one held. About 45 degrees is normal and with a good centre diff the pre load should be obvious. Disconnecting a drive shaft(s) is important to ensure full rotation isn't restricted by an axle diff. Without a CDL it's a bit more difficult as you need to 'feel' the take up in the centre diff.

It's worth noting that drive train slop is cumulative ie. front diff, centre diff and rear diff all wear and contribute to overall slop. As Rick notes ............ "IMO the best fix for this is an Ashcroft ATB...

It also takes so much backlash out of the t/car it isn't funny".

A characteristic of an ATB/Torsion type diff centre is that it effectively 'winds up' the drive train slop to give the feel of a slop free drive train. Whilst this might give a more 'enjoyable' driving experience with the benefit of a more efficient centre diff the downside is that it can mask the effects of wear/out of mesh in the comparatively weak D2 Rover diffs leading to avoidable failure. IMO using the ATB/Torsion diff to disguise the symptoms of wear could be a double edged sword.

Deano :)