Land Rover Freelander viscous coupling
This simple swap can lengthen a Freelander’s life significantly.
The Land Rover Freelander Series 1 doesn’t have the best reputation for reliability, and the four-wheel drive set-up is generally considered to be weak, certainly compared to the systems used on so-called ‘proper’ Land Rovers. As a result, many have been converted to two-wheel drive – a process which involves removing the propshaft and, depending on the model, making an electronic fix to trick the anti-lock braking system (ABS) into thinking nothing has changed.
Sometimes you’ll be told the propshaft’s been removed for economy reasons. Don’t believe it – the way in which the Freelander 4WD system works means that any benefit will be marginal at best, as we will see later. The only reason anyone removes a Freelander propshaft is because something – and usually something expensive – has broken.
How it works
The Freelander’s 4WD system has no transfer box as such, and is best thought of as a conventional gearbox-besideengine FWD setup with a Rwd-type propshaft and axle added behind. As usual, driveshafts run from the gearbox to the front wheels, and the output part of the gearbox – containing the differential – protrudes back from the main ’box, so the driveshaft to the offside wheel runs behind the engine.
On the Freelander, however, this is where an intermediate reduction drive (IRD) is bolted to the gearbox. This has two outputs: one that’s parallel to the input for the offside driveshaft, the other at 90°, facing rearwards and connected to a propshaft that takes drive to a Rwd-type rear axle/differential unit. To provide the ‘slip’ needed between
front and rear, and so that the 4WD operates only when actually needed, the propshaft is actually a two-piece unit incorporating an oil-filled viscous coupling unit (VCU) halfway down. When there’s similar load on the front and rear axles, the VCU transmits little or no drive and the Freelander is, to all intents and purposes, a FWD vehicle.
That’s why taking off the propshaft has almost no effect on economy – it’s in 2WD mode more often than 4WD anyway. However, if the grip at the back is reduced or lost – as might happen when driving off-road – the viscous coupling allows the drive to pass, giving 4WD when it’s actually needed. As the connection is provided by oil pressure rather than a mechanical link, the 4WD engages and disengages smoothly, so the rate of engagement and disengagement, and thus the amount of 4WD effort, are matched to exactly what’s needed.
What goes wrong
The drawback of this system is that, as with pretty much anything that relies on oil pressure, the Freelander’s 4WD couplings don’t last indefinitely.
Eventually, the VCU’S action will stiffen, before ultimately seizing completely. With no scope for movement between the front and back, tension will build within the system until something breaks. In most cases, it’ll be the IRD/ angle drive unit on the front or rear diff, though sometimes it can take out the main gearbox. Whatever happens, given the low market value of most first-generation Freelanders, a failure of this kind is usually considered an uneconomical repair.
Testing a VCU properly requires special equipment which is generally available only to reconditioners. Bell Engineering, one of the leading remanufacturers of Freelander drivetrain components, offers a free postal testing service, but even though you can still use the vehicle in 2WD mode while the propshaft is off, it’s hardly practical as a regular check.
A basic VCU inspection can be made by marking each side, taking the car for a brief drive, then seeing if the two marks are still aligned; if they are, the VCU has probably seized. However, while this will identify a fully-seized VCU, it won’t highlight one that’s starting to go – ie, if it’s still moving, but less than it should. That’s when you need to know there’s an issue. By the time it has seized, it’s likely some damage will already have been caused.
Other symptoms include difficult manoeuvring when doing tight turns, a feeling like brake drag when coasting to a stop, clunking and groaning sounds when parking, and a tendency to skid easily on loose surfaces. Finally, if raising the rear wheels on a jack causes one or both to spin momentarily as they are lifted off the ground, this is a sure sign of built-up tension within the drivetrain – tension most likely caused by a tight or seized VCU.
Unfortunately, while these tests can help, none will highlight issues until there’s already been a chance of damage. The best way of avoiding problems is to regard a 70,000-mile VCU change as part of the routine service schedule.
Incorrectly fitted parts
Over the past year or so, my partner Sarah’s Freelander has had a bit of history when it comes to drivetrain faults. It all started when she noticed some clonking underneath from the vicinity of the VCU. Our local garage – not a Freelander specialist – diagnosed worn VCU bearings and these were renewed. I subsequently discovered they’d fitted them the wrong way round and was warned that they might not last the course. About six months later, Sarah reported a knocking sound from the rear when reversing around sharp corners, especially up a slight incline. This is the classic first indication of a failing IRD. After confirming our diagnosis, a Freelander secondhand parts specialist in Staffordshire fitted a replacement.
Three months on, a loud noise was apparent on the overrun and seemed to be coming from the nearside front. It sounded like either the IRD had gone again or that there was a fault in the main gearbox – worrying as it’s an auto! Two local garages were asked to identify where the noise was coming from, but neither could give a definitive answer.
On recommendation, we contacted a Norfolk-based Freelander specialist called freelanderspecialist.com. It’s run by the husband-and-wife team of Sue and Norbert, who have extensive experience using and repairing Freelanders in conditions ranging from the wilds of Iceland to the Sahara desert, so drivetrain issues are something of a speciality.
Norbert took our Freelander for a testdrive. Within 20-30 yards, he was pretty sure the problem had nothing to do with either the gearbox or IRD, but was due to a noisy Vcu/propshaft bearing.
Back at the workshop, he removed the propshaft and spun it to confirm that one of the bearings had failed.
Sarah’s Freelander was on 115,000 miles, so well over the recommended 70,000 VCU change interval. It had been given a documented IRD change by a main dealer at 38,000 miles, so even if the VCU had been done at the same time, she was only 3000 under the limit. It took little persuasion to convince us to get the VCU changed at the same time. The step-by-step guide shows the key stages of the job.
Apart from needing to press the new bearings onto the VCU with a hydraulic press, it’s all straightforward DIY stuff. You don’t even need to jack up the Freelander for access – a couple of planks under the wheels on one side is the most you’ll need.
Expect to pay around £250 for a good quality exchange VCU, plus around £60 each for the bearings – GKN or genuine Land Rover parts are recommended – so you’re looking at £350-£400, plus an hour or two of not-too-arduous labour. But it’s only once every 70,000 miles and the alternative is much worse. And if our experience is anything to go by, you’ll find that because the front and rear are once again working in perfect harmony, the new VCU sharpens the car’s handling and cornering.
This is the rear axle/differential unit with the propshaft removed. It’s mounted on rubber bushes, one of which can be seen to the left of the drive flange. These deteriorate with use, but VCU problems shorten their life dramatically. Renewal is a bit fiddly, but generally straightforward.
This is the Land Rover Freelander’s IRD unit on a workbench. The left-hand side attaches to the gearbox output, the offside driveshaft goes into the right-hand side and the flange at the top connects to a two-piece propshaft which goes to the back. A failed VCU usually takes this out as well.
The VCU and propshafts off the car. The shafts are attached by four bolts and a flange at the front and rear, while the VCU is held by four bolts into captive nuts in the floorpan. Front and rear shafts each run through a press-on bearing, which are renewed with the VCU. There are poor-quality replacements around, so use GKN or Land Rover branded items.
This is the exchange VCU. New ones are available, but a reconditioned unit from a reputable supplier is fine. Do not try to cut corners with a secondhand VCU – even if you’re reinstating a previously-removed propshaft – as these are limited-life components which, if not functioning correctly, can cause very expensive damage.
As you can’t see very much of the shaft and VCU being separated with a spanner in place, this shows the immediate aftermath of dismantling. The slotted plate (on the right) holds the shaft onto the VCU – slacken the bolt and this can be removed, allowing the shaft to come off after a bit of persuasion.
You will need a ring spanner (19mm) to attach the front and rear propshafts to the VCU as there isn’t really room for a socket, and space is too tight for an open-ender. Again, note the use of white grease – it can be a struggle if the propshaft and VCU splines rust together.
The bearings need to be pressed onto the VCU and must be renewed with it as they’re virtually impossible to remove in one piece once fitted. They also have to go on the correct way round, with the wider side facing outwards as shown. The securing bolt is moved over and screwed into the replacement VCU. Note also the white grease on the propshaft splines.
These are the rear differential bushes (arrowed). As with most, ours had been weakened by the VCU problem, but it’s not too severe. New bushes will be needed, but with the cause of the VCU problem now fixed, replacing them can wait a while until there’s time.
White grease is needed on the flange connections, too. There’s no need to mark the differential or ICU and propshaft flanges to ensure they’re the same way round on reassembly as you’re renewing the big bit in the middle anyway, and the bearings prevent balance issues affecting anything.
The new VCU and bearings are bolted in place. With this done, the noise was gone. What we weren’t expecting was that cornering and handling now felt a good bit tighter and more precise. Before the change we had no idea that performance had tapered off by so much.