Loud bang, grinding noise , no drive. Gearbox , transfer box or driveshaft ?

Help please !
I was driving along in my Freelander 1 this morning when suddenly there was a loud bang followed by a metallic grinding and a complete loss of drive, got it home on truck. I thought it was the gearbox gone, but the tow truck driver said he thinks it is where the driveshaft joins the gearbox rather than the box itself. I am no mechanic so I don't know the correct terms exactly. I am wondering if it is the transfer box (whatever that is ) , the driveshaft, or really the gearbox ? The gearbox sounds like something is 'turning when I put it in gear but in park it still rolls. Can anybody point me in the right direction please ? I should probably mention that the car has been fwd only for a couple of years now due to the VCU failing. Reading up on the internet it sounds like the IRD has failed, is that the transfer box ?

The IRD is the Freelander equivalent of a transfer box. It takes drive out the gearbox and sends it to the front wheels and down the propshaft to the rear.
They are very susceptible to being damaged by incorrect tyres being fitted and or wrong tyre pressure, especially so if the VCU has stiffened up through over slipping, again by incorrect tyre replacement.
Basically the Freelander needs identical tyres all round, with the least worn on the back, or the AWD system is overloaded, causing expensive failures to occur.

Nodge68 said:

The IRD is the Freelander equivalent of a transfer box. It takes drive out the gearbox and sends it to the front wheels and down the propshaft to the rear.
They are very susceptible to being damaged by incorrect tyres being fitted and or wrong tyre pressure, especially so if the VCU has stiffened up through over slipping, again by incorrect tyre replacement.
Basically the Freelander needs identical tyres all round, with the least worn on the back, or the AWD system is overloaded, causing expensive failures to occur.

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Thanks for your reply Nodge68, as I mentioned I've been front wheel drive only for the last couple of years, so presumably my tyres aren't to blame. I was aware of that potential pitfall. I've managed to locate a second hand unit for about 80 quid, does anyone know if it's a big job replacing it ? ( I mean in hours of work not $$$). What a stupid system to have come up with, I can't understand the logic....

If it's FWD, then knowing the reason why it's FWD is helpful. Normally the rear output pinion begins to fail due to overloading by the VCU. At this point removing the propshafts help extend the IRD life, but it's not a permanent fix, just a way to extend the IRD life a bit longer.
As the output pinion bearing begins to collapse, metal is removed which gets into the oil, making an effective grinding paste which slowly destroys the rest of the internal moving parts which eventually fail with a load bang.

The AWD system is actually pretty robust, however it needs to be carefully looked after if issues are to be avoided. So tyres must be identical, correctly pumped up and pairs of new tyres must only go on the back, the ½ worn back tyres being moved to the front. Obviously if 4 new tyres are fitted, then fitted location doesn't matter, they simply need to be identical.

Follow this simply rule, and change the oils in the system every few years and it has a long life.

This isn't relating to wind up due to tyres/VCU as the VCU and props are not there. It could be due to previous wear within the transmission from it though.

If the gearbox is in Park and the car rolls - then there is no direct link from the gearbox to 1 or both front wheels - there should be to both.

From the gearbox you have a splined drive to the IRD. The IRD has a series of gears to and forming a differential for the front wheels. From the differential there is a direct drive to the RH wheel drive shaft and a splined drive to the LH wheel drive shaft.

So anything in the above list, including driveshafts, and even the wheel hubs, could cause the symptoms you are describing.

If 1 wheel has lost its 'connection' out from the diff (ie hub, driveshaft or splined drive to LH wheel), then with gearbox in park, the differential would simply turn allowing the car to roll.

Similarly, if something up to, and including, the diff has gone, then both wheels have lost connection.

So I suppose as diagnosis, you could lift the front end and see if 1 or both wheels turn when in park. As there is grinding, there could be a reasonable amount of resistance, meaning the wheel wouldn't necessarily turn freely. - edit, Hang on I'm thinking this is wrong - I'll update.

If only 1 wheel is turning, try to see if everything back to the IRD turns.

At the point it went 'bang', did you lose oil? Examine the IRD case - is it shattered? Its not unknown that a (RH) driveshaft support bearing has failed/collapsed causing gears in the diff to jam and shatter the IRD case.

Yeh, that method of diagnosis is wrong because the diff would simply spin with no connection to 1 wheel.

You could life the front and turn 1 wheel and see if the other turns in the opposite direction. This will at least let you know that everything from the diff onwards is in tact and the problem is likely in the splines from gearbox to IRD, or final drive from gearbox - if autos have a final drive and I don't know how park locks an auto box.

As there is grinding, you will need to hold the oposite wheel as that grinding would presumably be enough to turn the wheel even if there is a break somewhere.

It could also be the spline link tube through the gearbox, which is more common on the 1.8 than the other engine/gearbox combinations, but it can still fail with any model.

Nodge68 said:

If it's FWD, then knowing the reason why it's FWD is helpful. Normally the rear output pinion begins to fail due to overloading by the VCU. At this point removing the propshafts help extend the IRD life, but it's not a permanent fix, just a way to extend the IRD life a bit longer.
As the output pinion bearing begins to collapse, metal is removed which gets into the oil, making an effective grinding paste which slowly destroys the rest of the internal moving parts which eventually fail with a load bang.

The AWD system is actually pretty robust, however it needs to be carefully looked after if issues are to be avoided. So tyres must be identical, correctly pumped up and pairs of new tyres must only go on the back, the ½ worn back tyres being moved to the front. Obviously if 4 new tyres are fitted, then fitted location doesn't matter, they simply need to be identical.

Follow this simply rule, and change the oils in the system every few years and it has a long life.

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Its FWD because the VCU pretty much locked up which actually caused the rear diff to fail,actually about 5 years ago now (didn't realize it was that long}, I was on the way to Russia, so I removed the propshaft.

GrumpyGel said:

Yeh, that method of diagnosis is wrong because the diff would simply spin with no connection to 1 wheel.

You could life the front and turn 1 wheel and see if the other turns in the opposite direction. This will at least let you know that everything from the diff onwards is in tact and the problem is likely in the splines from gearbox to IRD, or final drive from gearbox - if autos have a final drive and I don't know how park locks an auto box.

As there is grinding, you will need to hold the oposite wheel as that grinding would presumably be enough to turn the wheel even if there is a break somewhere.

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GrumpyGel said:

This isn't relating to wind up due to tyres/VCU as the VCU and props are not there. It could be due to previous wear within the transmission from it though.

If the gearbox is in Park and the car rolls - then there is no direct link from the gearbox to 1 or both front wheels - there should be to both.

From the gearbox you have a splined drive to the IRD. The IRD has a series of gears to and forming a differential for the front wheels. From the differential there is a direct drive to the RH wheel drive shaft and a splined drive to the LH wheel drive shaft.

So anything in the above list, including driveshafts, and even the wheel hubs, could cause the symptoms you are describing.

If 1 wheel has lost its 'connection' out from the diff (ie hub, driveshaft or splined drive to LH wheel), then with gearbox in park, the differential would simply turn allowing the car to roll.

Similarly, if something up to, and including, the diff has gone, then both wheels have lost connection.

So I suppose as diagnosis, you could lift the front end and see if 1 or both wheels turn when in park. As there is grinding, there could be a reasonable amount of resistance, meaning the wheel wouldn't necessarily turn freely. - edit, Hang on I'm thinking this is wrong - I'll update.

If only 1 wheel is turning, try to see if everything back to the IRD turns.

At the point it went 'bang', did you lose oil? Examine the IRD case - is it shattered? Its not unknown that a (RH) driveshaft support bearing has failed/collapsed causing gears in the diff to jam and shatter the IRD case.

Click to expand...

Nodge68 said:

It could also be the spline link tube through the gearbox, which is more common on the 1.8 than the other engine/gearbox combinations, but it can still fail with any model.

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Thanks for your replies guys, am I correct in thinking that just replacing the whole IRD would cover all those problems ?

badlander said:

Thanks for your replies guys, am I correct in thinking that just replacing the whole IRD would cover all those problems ?

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It is unlikely - but I would rule out the drive shafts. They are a lot easier and cheaper to replace (once you have the hub nut off) and if it is them, then you have wasted a lot of effort and cash replacing the IRD.

If it is the splines that have gone - then you need to know if they are on the IRD or gearbox. I suppose the only way of telling is to remove the IRD - so if it doesn't cost to much, might be worth having a replacement IRD ready if it is the IRD side gone.

I don't know how the park lock works on the auto, I don't know if it is possibly that something, other than splines, has gone in the gearbox.

Do you still have the rear pinion attached to the IRD? If you do, when you roll the car, does it turn? That has a direct geared link to the gearbox. So if it turns, it is definitely the splines or gearbox that has gone. If you don't, you may be able to drain the IRD oil, remove the blanking plate and see if the pinion gear for the pinion turns - this would give the same info.

Dunno what others think.

IIRC Replacing an IRD should be no more than a couple of hours for a competent mechanic.
While it's true the system has flaws it is no different to any 4WD car in that the owner needs to be aware of issues caused by poor tyre maintenance or as Nodge mentioned different tyre sizes fitted. .

I've just been out to have a look, with the engine running and the car in gear, I can see the output from the IRD to the propshaft is turning. Also, if I try to put the car in park with the engine running it makes a nasty grinding noise as if the park "pin" is trying to engage but can't. Not sure if all this points to the gearbox rather than the IRD ? Another question is , the passenger side driveshaft seems to vibrate when the engine is running and car in gear, as if the splines are not located in the output from the gearbox, I don't know if the other wheel should still turn if the problem is this driveshaft ? The car is LHD. I'm at a loss as to where to start....

Alibro said:

IIRC Replacing an IRD should be no more than a couple of hours for a competent mechanic.
While it's true the system has flaws it is no different to any 4WD car in that the owner needs to be aware of issues caused by poor tyre maintenance or as Nodge mentioned different tyre sizes fitted. .

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As the car is only 2WD at the moment, all the tyre wear stuff is largely irrelevant, I previously had a Range Rover, Land rover series 3 and a Jeep cherokee, never had any troubles with these vehicles or heard of any tyre related problems.....

badlander said:

I've just been out to have a look, with the engine running and the car in gear, I can see the output from the IRD to the propshaft is turning. Also, if I try to put the car in park with the engine running it makes a nasty grinding noise as if the park "pin" is trying to engage but can't. Not sure if all this points to the gearbox rather than the IRD ? Another question is , the passenger side driveshaft seems to vibrate when the engine is running and car in gear, as if the splines are not located in the output from the gearbox, I don't know if the other wheel should still turn if the problem is this driveshaft ? The car is LHD. I'm at a loss as to where to start....

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I presume when you say that there is a vibration when...

when the engine is running and car in gear

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... that the car is not moving.

For the rear pinion to be turning, the gearbox and splines connecting the IRD to it are intact.

Drive will be getting to the differential (within the IRD) but something is broken from there on.

The RH drive shaft vibrating may mean the problem is that side, but not necessarily. It could be shock through gear from gears in the diff slipping, or maybe splines slipping driving the LH drive shaft. I take it the whole drive shaft is vibrating and not turning (including the CV cup against the IRD).

A differential will only provide torque to the wheel with least resistance. Normally both wheels offer the same resistance, so they get equal power. If a wheel loses traction, eg over a hole or on ice, then that wheel gets all the power and the wheel which could offer traction gets none - you're stuck - as you are now.

So first things first, make sure both drive shafts are fully inserted. Make sure you can not easily pull them back. They have circlips (?) that should lock them into their connections. Make sure nothing on either drive shaft turns - including the inward cups.

If they are inserted and a cup turns but not the rest of the drive shaft - then the CV has failed.

If nothing rotates, I'd be pulling the drive shafts out on their connectors - jack the car up, remove the 2 bolts holding hub to strut, pull the hub away rotating on the bottom ball joint, then pop the drive shaft from its connector (on the IRD on RH and gearbox on LH). As they come out ensure no bits of metal fall out and that the splines on the end of the shafts are intact.

That would confirm the splines on the drive shafts are OK and the splines they connect to.

If they are, then either the diff in the IRD has failed or the splines from the IRD to the shaft through the gearbox to the LH wheel. Either of these will be resolved with a replacement working IRD - unless the broken splines are on the shaft going through the gearbox.

Once again, others may have different ideas.

badlander said:

As the car is only 2WD at the moment, all the tyre wear stuff is largely irrelevant, I previously had a Range Rover, Land rover series 3 and a Jeep cherokee, never had any troubles with these vehicles or heard of any tyre related problems.....

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These are all different types of 4WD - either full time (with a center diff) or switchable.

Ali should really have said AWD rather than 4WD. AWD vehicles, like the Freelander, are all dependent on closely matching tyres. That also extends to an extent to the likes of late RR classics and P38 that have a viscous coupling in the center diff rather than a manual lock facility.

GrumpyGel said:

I presume when you say that there is a vibration when...
... that the car is not moving.

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Correct

GrumpyGel said:

For the rear pinion to be turning, the gearbox and splines connecting the IRD to it are intact.

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That's good

GrumpyGel said:

A differential will only provide torque to the wheel with least resistance. Normally both wheels offer the same resistance, so they get equal power. If a wheel loses traction, eg over a hole or on ice, then that wheel gets all the power and the wheel which could offer traction gets none - you're stuck - as you are now.

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That's what I thought

GrumpyGel said:

The RH drive shaft vibrating may mean the problem is that side, but not necessarily. It could be shock through gear from gears in the diff slipping, or maybe splines slipping driving the LH drive shaft. I take it the whole drive shaft is vibrating and not turning (including the CV cup against the IRD).

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I'm not sure, I'll check

GrumpyGel said:

If they are, then either the diff in the IRD has failed or the splines from the IRD to the shaft through the gearbox to the LH wheel. Either of these will be resolved with a replacement working IRD - unless the broken splines are on the shaft going through the gearbox.

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It's looking like that is the best option, but I guess I'd better pull the driveshafts first ?

Thanks for taking the time to give me a clear understanding of what the problem may be. I really appreciate it very much.

It appears to be inside the IRD, differential I guess

badlander said:

It appears to be inside the IRD, differential I guess

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I'm of that opinion. If the RH drive shaft is moving, it suggests something has failed inside the IRD. However it could be the splines on the drive shaft. I'd be removing the RH drive shaft for a look, it'll need to come off to replace the IRD anyway, so it's not time wasted.

Nodge68 said:

I'm of that opinion. If the RH drive shaft is moving, it suggests something has failed inside the IRD. However it could be the splines on the drive shaft. I'd be removing the RH drive shaft for a look, it'll need to come off to replace the IRD anyway, so it's not time wasted.

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Thanks Nodge, I'll give it a go tomorrow, wouldn't be good to order the IRD which is 1000km away only to find it was the driveshaft ! Thanks for your help.

Does the gearbox have to come out to fit the IRD ?