Good luck. Having drilled and tapped this hole myself (but with the unit off the car and stripped), the problems are;
1). Creating a smooth surface on the PTU boss face for the sealing washer to bed against.
2). Drilling the hole perpendicular to the smooth face
3). Getting the swarf and tapping cuttings out.

See my earlier posts with internal photos of my stripped PTU - even after drilling this hole, you will not get all the oil out because there 3 compartments at the bottom of the unit. From experience, I found I could suck out (using a soft tube and compressor driven suction/brake bleeder) nearly as much as can be drained out. I now have a different Freelander and would not bother to drill this drain hole.

Ok so today after several days of rain we got a dry day and i completed the PTU drain hole & added a drain plug.

This is on TD4 MY 07 Tambora Flame, yet to carry out the same job on the Orkney Grey SD4 MY14.

I had already cleaned and made a flat surface, all will be on my thread of PTU.


1

6mm Drill hole first then moved up to 8.5mm
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5

Left to completely drain before tapping.
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https://www.freel2.com/forum/topic39481-45.html

Last edited by Arctic on 26th May 2024 10:02 am. Edited 1 time in total

Bumpf wrote:

My post a couple of weeks ago was based on my research for fixing the noisy PTU on my 2013 TD4 which has travelled just 78,000km. I'm not surprised that it's happened at such low Kms since I previously had a 2011 TD4 which developed the same problem at 80,000km and I put up with the increasing irritating noise until the PTU was swapped out at 119,000km by LR under 'warranty' when the car was nearly 6 years old! It then performed perfectly until I sold it at 215,000Km.

With my current car, I thought I could hear at 50-60 kph the characteristic whirring noise of the PTU failed bearings. I got under the car and tried moving the front of the prop shaft with my hand. I could see, feel and hear 1-2mm of freeplay left/right and back/forwards. See video: https://www.youtube.com/shorts/PaAzBU0bVsc

Whilst I could probably have put up with the noise a bit longer but I knew it would get louder so decided to fix it. I felt confident that since I had caught this issue at an early stage, that the PTU gears would suitable for a rebuild.

I'm in Perth, Australia. I considered importing a refurbished unit from the UK but all options were expensive due to freight costs. Note Bell Engineering does not export outside the UK. There are transmission rebuilders here in Perth WA, including exchange units. Garages were not keen to remove/rebuild/refit the PTU as it ties up a vehicle lift for at least 2-days.

I came across 'Max' who an 80-year old engine and transmission expert and LR enthusiast, who agreed to rebuild my PTU in his workshop whilst I watched. He's a bit of a legend in the LR world. The V8 6-litre automatic Series One landrover he built around 1980 made a big impression!

I decided to remove and refit the PTU myself for the fun of it! It took me 4 hours to remove the PTU on my drive. It was straight forward apart from releasing the steering knuckle bottom ball joint. It's under compression so the usual hit with a hammer to break the taper didn't work. I had to Uber to the local Supercheap store to buy a clamp tool which I had to file to widen the jaw gap to 25mm. The tool broke the taper and then I used a 650mm length of 30x30mm angle iron as a lever to push the lower control arm down.

Watching and chatting with Max as he stripped and then rebuilt the PTU was entertaining, highly educational and a privilege. He has amazing mechanical knowledge and experience - I wish it could all be copied to a computer file for posterity.

The small pinion bearing propshaft end) was badly pitted and the large pinion bearing lightly scored. The main crown wheel bearings were both in good condition. The crown wheel and pinion were undamaged. Max fitted all new bearings and swapped out some of the shims to ensure optimised pre-load and crown/pinion engagement. He milled a flat seating and drilled/tapped to add an M8 drain plug.

He has rebuilt many Freelander/Evoque rear differentials, and a smaller number of PTUs, all due to pinion bearing failure. His view is that the issue is almost certainly due to excessive preload during manufacture.

Refitting the PTU was a straight-forward reverse process, completed with assistance from a mate in 3 hours.