As an update, I connected a 6 point electronic stethoscope to various areas under the car and narrowed the clunk down to the transfer box casing and I have decided to change the chain inside and while I am there, the main input and output bearings and seals. At least that way I know it's done.

I am looking for advice really as to any potential pitfalls in removing the transfer case and stripping it down. I will be doing it mostly on my own and on my drive but will hopefully recruit my 16 year old for removing the exhaust and transfer box.

Any tips or ideas much appreciated

Not sure how easy it is to view from under the vehicle because of the subframe getting in the way but the Hy-Vo chain and sprocket can be seen through the drain plug hole. You could maybe use a screwdriver to lever the chain away from the sprocket to get an idea of how tight (and therefore worn) it is?

Thanks Phil, hope you are well. I will take a look tomorrow.

As part of the removal, could I also possibly feel for back lash in the output drives once the front and rear prop shafts are removed ?

I have all the parts so if the removal is going well I may just do the refurb anyway.

Are they easy to take apart ?(keeping in mind I am a novice)
Thanks
Andy

Bit of an update, I am so far 4 days in to taking out my transfer box, replacing the chain and main bearings, input and output seals.

I had all the parts already as I was convinced this was my clunk, as a couple of others have found, so I went ahead and took it out.

I have a nasty feeling, as I think Bemble has mentioned in the past, that there was nothing wrong with my transfer box.

When I say there was nothing wrong, there could be now, tomorrow will tell as I am not 100% sure I put it back together correctly as there is a distinct lack of information regarding rebuilding the NV225, probably because they are so reliable.

It has been a mixture of surprisingly easy to get out, under 3 hours, and a complete $%^&! at times, a lot to do with being on my own with a cramped and quite frankly disorganised working space.

I reckon i could have saved at least a day if I had the correct snap ring pliers (now ordered) and a transmission scissor jack for replacing transmissions with the vehicle on the ground and probably another day if I had my buddy Loony, Ex F1 mechanic, to help but he is out of commission currently, although his dad, probably about 50 years working as a motorsport and F1 technician, has been lending me tools and advice.

Only the exhaust pipes to put back on tomorrow and then I shall fire it up and see if the transmission explodes into a hail of gears and bearings..

When I connected the electronic stethoscope as shown in the image, the loudest bang noise came from the transfer box after connecting to various components around the car, although looking at the image, this is where the front propshaft connects and knowing the front CV joints need attention, the sound could have been transferred down the shaft.

Anyway, my typing is just therapy, I have loads of fots to add, so i could write up a simple 'how to' or most likely, 'why not to'...

In short, it seems to drive ok and high low shift works ok, however my clunk is no better, hopefully i haven't caused any long term issues with the TB...........

holidaychicken said:

In short, it seems to drive ok and high low shift works ok, however my clunk is no better, hopefully i haven't caused any long term issues with the TB...........

Click to expand...

Sure you will be fine Andy, as long as the clonk is no worse, then you haven't made anything worse..!!!

Love to see a How To written for this!

Regards clonk....have you thought of the rear prop bearing that is by the fuel tank?? Just a thought....

Driveline clonks and knocks are a bitch to locate, so many moving parts to eliminate!

Cheers Ant, clonk is not worse, it's always a bit nerve racking stripping things down for the first time, especially transmission components.
There is a couple of 'Detents' in the TB that fall out of nowhere which panicked me a bit but i think I have found where they go.

The rear prop bearing looked ok, you have to remove it when taking out the TB if its the one on the attached fot.

The front suspension arms, joints and CV joints are on my list of jobs as I get various clicks and clonks when manoeuvring.

I am not ruling out engine mounts either. I bought a new TB mount but didn't have time to make a tool to remove the old one but it felt really solid compared to the new one.

I sort of enjoy this, but at times when things are going a bit wrong it's a total and utter sh1t..

Cheers for the input though mate, keeps me sane

Yeps that's the kiddy....if that seems sound then it ain't the rear prop moving in the bearing then..!!

You'll be surprised how much knocks and bangs about with worn suspension bushes etc.

See they ain't bad old busses to work on as long as you don't rush yourself and take yer time...having the use of another car helps to relieve the time pressures!!

That bearing seemed ok, I got hold of it and gave it a good wiggle, I think it's rubber mounted, well I hope it is. The prop shaft itself looked in good condition as it's mainly shielded from the road.

Something that was interesting was a grommet above the transfer box that allows the transmission selector cable to pass through, mine had popped inside the car so if i ever went wading the bloody car would fill up through a hole about 25 mm in diameter.

To be fair it does feel better now i have driven it more as the new chain was slightly tighter than the old one but it's not cured.

I have done the main upper and lower bushes at the rear so i will see what the front brings. I am gradually replacing the whole car a piece at a time.

Ideally I need to get it on a ramp with all 4 wheels in the air and start it up and put it in drive and see what slops around, i suppose I could use 4 axle stands but if it falls off it might go through my house!

When it's perfect or i am bankrupt, I will sell it :crazy:

holidaychicken said:

......

When it's perfect or i am bankrupt, I will sell it :crazy:

Click to expand...

Dibs on the Faultmate

Sell ti and you'll regret it, they are a disease and you'll get a hankering for one again!

Axle stands are not a good idea, they L322 is fat ol' bitch and with that much mass sitting astride axle stands gives me the eebbie jeebbies .... unles you get some fecking heavy duty ones and ensure they are FIRMLY located!

No bother on the faultmate , , mate i don't think I could sell the range unless it was to buy a 5.0 supercharged vogue, 500 BHP +.

I do have some good axle stands but it's a case of who do i trust to sit in it while i look underneath for wobbly bits .

More likely drive the 35 miles to my brother who has a 4 post lift for his business renovating old classic cars like VW campers and old fords

Well i have been under the rangie again today as my clunk is still getting on my tits.

The things i have done so far are rear suspension bushes and track rods, transfer box chain and bearings, now front suspension arms cv joints and ball joints, which has improved things as the rubber bush in one bottom arm was almost broken through, checked the engine mounts using a webcam and also my stethoscope, gearbox mount was ok, all the CV joints and rubber couplings seem ok.
I did a recheck using the 6 point electronic stethoscope all over the car and the loudest clunk is when i clip a microphone onto the drain plug of the transfer box.

If i jack up one front wheel i can turn it a fair amount and the driveshaft and front propshaft turn an equal amount into the transfer box, but there is no movement in the rear propshaft which again points to back lash in the TB but being that the chain is new i wondered if the diff in the TB was worn or maybe they are just like this.

The best way for me to recreate my issue is to accelerate very gently down a shallow decline, let the throttle off which relaxes the drive train and then give the accelerator a light jab and i get a bang in the drivetrain which feels like it comes from the centre of the car i think.

Its annoying as when i am turning into my road, it is on a slight decline and then when i accelerate again i get the bang which is driving me nuts.

if anyone could try the same test with theirs it would be very very much appreciated as maybe this is just the way they are as there is a lot of mechanics going on with the 4 wheel drive but i cant believe they are like this from new.

Well this is STILL driving me absolutely mad !!!
I took the car to an indy and we put it up on a ramp and checked for play in the driveshafts, propshafts, joints etc and couldn't see anything obvious and we compared to another L322 which was newer but had 180k miles on it and it was pretty much the same play in the drivetrain but we couldn't drive it but one thing that did come up was the Autologic diagnostic kit said i needed an engine ECU software update but it wasn't entirely clear which program was correct so we left it.

It got me thinking about whether the problem is engine related by the revs dropping to much when slowing down or the transmission ECU software needing an update as i did find a ZF fault diagnosis flowchart online and the exact same issue is resolved on the 2006 models by an engine ECU update.

My problem to recap is when I slow right down but don't come to a complete stop and then accelerate i get a bang or a clunk, if i come to a complete stop it is perfect when i accelerate and it doesn't really do it when i am in higher gears as far as I can tell.

If i can't resolve this i am contemplating selling it on as it ruins the driving experience as i now focus on it whenever i drive it, (maybe it's me that needs therapy)
I am considering taking it to a another indy now with T4 testbook to see if they can update the ECUs and i did notice that there is a later version of the same ECU available, the early part being NNN000390, which has been superseded by NNN500400.
I rebuilt the transfer box, replaced front suspension arms, the car has had the transmission rebuilt and the torque converter refurbished, rear suspension arms, outer cv joints.

The loudest noise is when i connect up my electronic stethoscope to the drain plug on the transfer box so in my mind it is coming from the front as this is next to where the front propshaft connects and it does generally feel like it's coming from the front.

The same issue is on the X5 forums with as many cures as there are people posting the same problem.

I am considering a reward for anyone that can solve this for me as i really want to enjoy the car now i have spent a fortune on it but this is keeping me awake at night.
Please help me before I go (more) insane

Hello, did you figure out what this is ? I can't figure it out and was hoping you might've ?

Not really is the answer other than i learned to live with it.
i had rebuilt the transfer box and changed the outer cv joints and i did change the oil in the front diff which i think improved things slightly and did give the engine a good going over with the faultmate but my thinking is it's a combination of lots of cv joints and mounts all slightly worn and it's possibly just the way it is as i have started to ignore it and just drive the thing and the only time it does it is when i am turning into my road which is on a slight downward slope so when i throttle off there is a bit of over run which causes the driveline to go slack so that when you throttle back on again i get the bump.
There is a very similar issue with the later 2005 onwards vehicles which is resolved by an engine and transmission ECU software upgrade but i never got around to going to the main dealer to check if there is an upgrade for mine but i did notice the later vehicles had a different part number for the engine ECU and the Indy i visited had a different diagnostic tool which did recommend an upgrade but i chickened out incase it rendered the vehicle useless.

What is your doing as it can be transfer box chain or engine mounts or cv joints or or or ...?

Mine mainly manifests itself when i pull away, let the throttle off and then back on again without stopping, if i come to stop the engine takes up the slack and there is no noise.

Mine is exactly the same symptom as you describe. Gentle on the throttle at pull away and all good, however let off throttle and re-apply and it's like a small shunt like something has slack in it. I cant remember if the other l322's I drove had it...

Doesn't feel engine related however I do have a MOST updated model but with BMW engine.

I've checked underneath the car and there is some amount of driveline slack in the prop but doesnt seem untoward. Maybe something to do with the auto boxes engagment ? I guess you have changed the fluid on yours.

I dont want to take it to a garage because they could charge LOTS to look for the issue, than again it may be something they know

holidaychicken said:

Not really is the answer other than i learned to live with it.
i had rebuilt the transfer box and changed the outer cv joints and i did change the oil in the front diff which i think improved things slightly and did give the engine a good going over with the faultmate but my thinking is it's a combination of lots of cv joints and mounts all slightly worn and it's possibly just the way it is as i have started to ignore it and just drive the thing and the only time it does it is when i am turning into my road which is on a slight downward slope so when i throttle off there is a bit of over run which causes the driveline to go slack so that when you throttle back on again i get the bump.
There is a very similar issue with the later 2005 onwards vehicles which is resolved by an engine and transmission ECU software upgrade but i never got around to going to the main dealer to check if there is an upgrade for mine but i did notice the later vehicles had a different part number for the engine ECU and the Indy i visited had a different diagnostic tool which did recommend an upgrade but i chickened out incase it rendered the vehicle useless.

What is your doing as it can be transfer box chain or engine mounts or cv joints or or or ...?

Mine mainly manifests itself when i pull away, let the throttle off and then back on again without stopping, if i come to stop the engine takes up the slack and there is no noise.

Click to expand...

I have an amount of driveline slack in the propshafts but i think that's normal.
Regarding the transmission, we stripped that down completely a couple of years back but one of thing i was going to try at some point was to make sure the box is full to the brim with fluid as i haven't checked it since we did the rebuild but if you going to try that make sure you follow the procedure of filling and checking with the engine running otherwise it will pee out all over the place if the engine is off.

I paid for an indy to spend an hour on it but they couldn't find anything wrong but feel free to have a try, it would be interesting to see what they say.

When i was checking the engine is was for basic air leaks in case the engine revs were dropping off too much when i throttled off and i would imagine the later model upgrade would feather the throttle rather than allowing it to accelerate from idle with a snap.

Whats a MOST updated model ?

It's not only your driveline that has slack in it, and you aint normal. Morning Andy

I know and I know, I have been 'serviced' too many times by the main dealer, still everybody has got to make a living !
Evening Alan

holidaychicken said:

I know and I know, I have been 'serviced' too many times by the main dealer, still everybody has got to make a living !
Evening Alan

Click to expand...

Evening Andy, thought you had seen your arse as it took so long to reply. Would hate to fall out.Cannot find the kissy smilie.