Haldex Unit

Montyfreelander · Mar 9, 2023

Hi. I'm hoping that someone on here can advise me (please!). I have a 2007 FL2 2.2 diesel, works fine in 2 wheel drive (when terrain selection options are switched off), but today when I needed the 4 wheel drive (because of the snow), I discovered the 4 wheel drive doesn't work!

I jacked the car up and put it on axle stands, so all 4 wheels were off the ground. I started the car and selected 'Snow' setting, put it into 1st gear and let the clutch out. The front wheels turned as normal, the prop shaft turned, as normal, but nothing from the back wheels! I assume that the Haldex Unit is to blame? I don't mind so much, because I can pick up a used replacement for around £350, but I don't want to spend that money if it's not going to make any difference. Any comments will be most welcome. Thanks

Stv123 · Mar 9, 2023

Not necessarily, it could be a whole host of different things. Perhaps Haldex is low on fluid, the pump has failed, the control unit is not getting a signal? Or many other. You really need to ascertain the fault before taking the plunge.

GrumpyGel · Mar 10, 2023

Knowing how many people report that errors are thrown on the dash relating to reduced traction type problems, I would have thought that the 4wd 'brain' (computer - is that 'terrain response'?) does self tests to the Haldex unit to know its there and can pick up commands issued to it.

So it will be issuing commands. They obviously are not resulting in the desired effect.

Haldexes are notorious for not being serviced properly and not functioning properly. A good thoughrough service would therefore be advisable... but that may be wasted cash it it turns out to be totally shagged and needs replacement.

What rings in my ears though is how rubbish the early F2 diffs were. As there is absolutely no torque getting through to the driveshafts (they don't turn at all even when off the wheels are off the ground), I wouldn't mind betting someone has had diff problems in the past and the cheapest option at fixing them was to remove the gubbins (planetry gears) in the diff. This is, in a way similar to a 2WD IRD in a F1.... remove a gear(s) to stop drive causing problems.

Nodge68 · Mar 10, 2023

Montyfreelander said:
Hi. I'm hoping that someone on here can advise me (please!). I have a 2007 FL2 2.2 diesel, works fine in 2 wheel drive (when terrain selection options are switched off), but today when I needed the 4 wheel drive (because of the snow), I discovered the 4 wheel drive doesn't work! I jacked the car up and put it on axle stands, so all 4 wheels were off the ground. I started the car and selected 'Snow' setting, put it into 1st gear and let the clutch out. The front wheels turned as normal, the prop shaft turned, as normal, but nothing from the back wheels! I assume that the Haldex Unit is to blame? I don't mind so much, because I can pick up a used replacement for around £350, but I don't want to spend that money if it's not going to make any difference. Any comments will be most welcome. Thanks

First off, the Freelander 2 has a fully automatic AWD system, so will be AWD when needed, regardless of the position of the TR dial.

The different selections simply alter the traction control, throttle response and gear selection points (if automatic) and not much else. Basically leaving it in the default position will do all most road conditions require.

Now as to there being no drive to the rear. This is pretty common, and not related to the Haldex at all.
Unfortunately lack of drive to the rear is most likely due to the stripped splines of the link tube between the gearbox PTU.
The only cure is a replacement PTU and new splined link, which needs greasing correctly when fitting. Unfortunately LR didn't use sufficient grease when the vehicle was built, which results in the splines fretting and wearing out somewhere between 60 and 100k miles.

Don't be tempted to buy second hand, as all these units suffer the same way. Get a reconditioned unit from Bell Engineering, and a new link tube too. It's about a 5 hour job to replace the PTU, providing the spline tube comes off the gearbox, which isn't always the case.

Testing the PTU is easy. Simply see if you can turn the propshaft by hand with the wheels on the ground. If it turns, the PTU is definitely fubar.

Montyfreelander · Mar 10, 2023

Nodge68 said:
First off, the Freelander 2 has a fully automatic AWD system, so will be AWD when needed, regardless of the position of the TR dial.

The different selections simply alter the traction control, throttle response and gear selection points (if automatic) and not much else. Basically leaving it in the default position will do all most road conditions require.

Now as to there being no drive to the rear. This is pretty common, and not related to the Haldex at all.
Unfortunately lack of drive to the rear is most likely due to the stripped splines of the link tube between the gearbox PTU.
The only cure is a replacement PTU and new splined link, which needs greasing correctly when fitting. Unfortunately LR didn't use sufficient grease when the vehicle was built, which results in the splines fretting and wearing out somewhere between 60 and 100k miles.

Don't be tempted to buy second hand, as all these units suffer the same way. Get a reconditioned unit from Bell Engineering, and a new link tube too. It's about a 5 hour job to replace the PTU, providing the spline tube comes off the gearbox, which isn't always the case.

Testing the PTU is easy. Simply see if you can turn the propshaft by hand with the wheels on the ground. If it turns, the PTU is definitely fubar.

Thank you, I'll try the test you suggested and see what happens. (I didn't know that about the F2 having a fully automatic AWD system! Every day is a school day.)

GrumpyGel · Mar 10, 2023

Nodge68 said:
First off, the Freelander 2 has a fully automatic AWD system, so will be AWD when needed, regardless of the position of the TR dial.

The different selections simply alter the traction control, throttle response and gear selection points (if automatic) and not much else. Basically leaving it in the default position will do all most road conditions require.

Now as to there being no drive to the rear. This is pretty common, and not related to the Haldex at all.
Unfortunately lack of drive to the rear is most likely due to the stripped splines of the link tube between the gearbox PTU.
The only cure is a replacement PTU and new splined link, which needs greasing correctly when fitting. Unfortunately LR didn't use sufficient grease when the vehicle was built, which results in the splines fretting and wearing out somewhere between 60 and 100k miles.

Don't be tempted to buy second hand, as all these units suffer the same way. Get a reconditioned unit from Bell Engineering, and a new link tube too. It's about a 5 hour job to replace the PTU, providing the spline tube comes off the gearbox, which isn't always the case.

Testing the PTU is easy. Simply see if you can turn the propshaft by hand with the wheels on the ground. If it turns, the PTU is definitely fubar.

Not saying the splines aren't faulty - but with the 4 wheels off the ground, the front wheels and the prop shaft turned, but not the rear wheels.

Would there have been some drag on the prop, to make it turn, but not enough to then pass torque through to the read axle?

Montyfreelander · Mar 10, 2023

Nodge68 said:
First off, the Freelander 2 has a fully automatic AWD system, so will be AWD when needed, regardless of the position of the TR dial.

The different selections simply alter the traction control, throttle response and gear selection points (if automatic) and not much else. Basically leaving it in the default position will do all most road conditions require.

Now as to there being no drive to the rear. This is pretty common, and not related to the Haldex at all.
Unfortunately lack of drive to the rear is most likely due to the stripped splines of the link tube between the gearbox PTU.
The only cure is a replacement PTU and new splined link, which needs greasing correctly when fitting. Unfortunately LR didn't use sufficient grease when the vehicle was built, which results in the splines fretting and wearing out somewhere between 60 and 100k miles.

Don't be tempted to buy second hand, as all these units suffer the same way. Get a reconditioned unit from Bell Engineering, and a new link tube too. It's about a 5 hour job to replace the PTU, providing the spline tube comes off the gearbox, which isn't always the case.

Testing the PTU is easy. Simply see if you can turn the propshaft by hand with the wheels on the ground. If it turns, the PTU is definitely fubar.

Thank you for your comment. It's funny you should say that - as when I bought the car 5 years ago, I returned it the garage I bought it from complaining of a whining noise coming from the back end/diff area. They kept it a week then returned it, telling me they had fitted a recon diff. I now suspect (strongly), all they did was remove some of the gears from the diff and put it back together (they have since gone out of business by the way!). I mentioned this to a LR specialist garage yesterday and they said it would be unlikely, as the drive shafts would need 'gears' to support them!?

Montyfreelander · Mar 10, 2023

GrumpyGel said:
Not saying the splines aren't faulty - but with the 4 wheels off the ground, the front wheels and the prop shaft turned, but not the rear wheels.

Would there have been some drag on the prop, to make it turn, but not enough to then pass torque through to the read axle?

I did think of that, (does the car need resistance of some sort to pass power to the rear?), so I'm not sure about that one!

Montyfreelander · Mar 10, 2023

Stv123 said:
Not necessarily, it could be a whole host of different things. Perhaps Haldex is low on fluid, the pump has failed, the control unit is not getting a signal? Or many other. You really need to ascertain the fault before taking the plunge.

Thank you. That's really what I needed to hear!

Nodge68 · Mar 10, 2023

Montyfreelander said:
Thank you, I'll try the test you suggested and see what happens. (I didn't know that about the F2 having a fully automatic AWD system! Every day is a school day.)

It is AWD regardless of the dial position. When pulling away from stationery, the AWD engages regardless of if it's needed or not. This is most likely the main reason all components in the AWD system have a limited life. Basically there's no need for the Haldex to activate when starting from rest on a warm sunny day on tarmac, but it does, which puts enormous strain on all AWD components, especially if odd tyres are used.

If the rear diff is suspected, then it's easy to test.
Just lift the rear wheels from the ground and rapidly rotate one forwards and backwards a few degrees. If the gears inside are working correctly, you'll hear them clattering as they take up the slack.

Montyfreelander · Mar 10, 2023

Nodge68 said:
It is AWD regardless of the dial position. When pulling away from stationery, the AWD engages regardless of if it's needed or not. This is most likely the main reason all components in the AWD system have a limited life. Basically there's no need for the Haldex to activate when starting from rest on a warm sunny day on tarmac, but it does, which puts enormous strain on all AWD components, especially if odd tyres are used.

If the rear diff is suspected, then it's easy to test.
Just lift the rear wheels from the ground and rapidly rotate one forwards and backwards a few degrees. If the gears inside are working correctly, you'll hear them clattering as they take up the slack.

That makes sense. I've done that test and nothing, no sounds, no resistance and certainly no movement from the opposite wheel.

Nodge68 · Mar 10, 2023

Montyfreelander said:
That makes sense. I've done that test and nothing, no sounds, no resistance and certainly no movement from the opposite wheel.

Maybe someone has removed the planet gears, although it's not a common bodge that I'm aware of, especially as it's the tail bearing which fails.

Unfortunately the opposite wheel doesn't always rotate when turning the rear wheels, as any drag on the parking brake shoes would simply cause the diff pinion to rotate the Haldex output shaft.

It's possible that the rear diff has been gutted of planet gears and pinion, but it's a lot of work for no real gain, other than spending a few ££ on a rebuilt diff.

Your best bet now is to see if the propshaft is connected to the front diff, so try to turn it and see what happens. If it spins free the PTU is at fault. If you can't turn it, then it's potentially a rear diff issue, so more investigation will be needed.

Montyfreelander · Mar 10, 2023

Nodge68 said:
Maybe someone has removed the planet gears, although it's not a common bodge that I'm aware of, especially as it's the tail bearing which fails.

Unfortunately the opposite wheel doesn't always rotate when turning the rear wheels, as any drag on the parking brake shoes would simply cause the diff pinion to rotate the Haldex output shaft.

It's possible that the rear diff has been gutted of planet gears and pinion, but it's a lot of work for no real gain, other than spending a few ££ on a rebuilt diff.

Your best bet now is to see if the propshaft is connected to the front diff, so try to turn it and see what happens. If it spins free the PTU is at fault. If you can't turn it, then it's potentially a rear diff issue, so more investigation will be needed.

Hiya. I tried to rotate the prop shaft (with the car in 1st gear and all 4 wheels on the ground) and it would not turn. Looking like the rear diff! (or possibly the Haldex?)

Nodge68 · Mar 10, 2023

Ok, so you have a connection to the front, so the issue must be at the back.
It'll only be the Haldex or diff.
Your best be is to remove the Haldex for inspection and cleaning, which isn't as hard as it sounds. You can also check the diff pinion at the same time.

Montyfreelander · Mar 10, 2023

Nodge68 said:
Ok, so you have a connection to the front, so the issue must be at the back.
It'll only be the Haldex or diff.
Your best be is to remove the Haldex for inspection and cleaning, which isn't as hard as it sounds. You can also check the diff pinion at the same time.

Yeah, thank you. I'll try that and post an update afterwards.

Nodge68 · Mar 10, 2023

Montyfreelander said:
Yeah, thank you. I'll try that and post an update afterwards.

Make sure you get a service kit for the Haldex too.

GrumpyGel · Mar 10, 2023

Montyfreelander said:
I mentioned this to a LR specialist garage yesterday and they said it would be unlikely, as the drive shafts would need 'gears' to support them!?

Maybe this garage designed the initial F2 diffs and that is why they are so bad.

No driveshaft is going to be supported by gears - that's a stupid suggestion.

They will be supported by bearings. Whether there are any gears in the diff for the gears on the end of the drive shafts to mate to is another question.

Nodge's suggestion of lifting a wheel and turning it is a good one to help diagnosis. If the diff has its gears, then turning the wheel would mean that the wheel on the other side should turn in the opposite direction or the prop shaft should turn. The other wheel won't turn because its on the ground, so the prop should turn. However, you definitely have no transfer of torque between drive shafts and prop shaft - so the prop won't turn (it won't anyway because of the gears at its other end) - so you need to determine if the 'break' is in the diff or Haldex - listening/feeling/sensing for gears connecting in the diff is going to be your task. Is the drive shaft "free wheeling" inside the diff, or are those gears there and the free wheeling is in the Haldex?

Anotyher of Nodge's suggestions may be your best solution - taking it to Bell Engineering. They should be able to tell you what's wrong and supply decent parts to resolve the problem.

Nodge68 · Mar 10, 2023

GrumpyGel said:
No driveshaft is going to be supported by gears - that's a stupid suggestion.

It's actually normal.
The diff carrier assembly is also the drive shaft support bearing. There's no need for a separate drive shaft support bearing, as for 99% of the time, the diff carrier is rotating at the same speed as the drive shafts going through it.

GrumpyGel · Mar 11, 2023

Nodge68 said:
It's actually normal.
The diff carrier assembly is also the drive shaft support bearing. There's no need for a separate drive shaft support bearing, as for 99% of the time, the diff carrier is rotating at the same speed as the drive shafts going through it.

Using the F1 diff as an example, is it not the job of these bearings to support the drive shaft? ...

Nodge68 · Mar 11, 2023

GrumpyGel said:
Using the F1 diff as an example, is it not the job of these bearings to support the drive shaft? ...

View attachment 284257

Actually the FL1 diff is pretty unique, as it does actually have separate support needle bearings for the driveshafts.
This is very unusual for a diff that uses splines on the end of the CV joint like the Freelander. I suspect this was done to keep the CV joints in alignment at steep articulation angles with relatively short shafts.
Normally only flange output diff designs use separate support bearings for the flanges, as there would be no way prevent the output flanges from moving under side loads.

The Freelander 2 rear diff is more conventional, having only enough bearings to support the diff assembly itself, and none for the drive shafts. The shafts are very long, so articulation angles are minimal in this instance.

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