Whining noise on 4th and 5th gear while accelerating, Td5 2001

Hello fellow Defender owners,

I've finely combed the forum to find a similar problem, or solution, but nothing that has caught my eye yet. Now humbly asking you to share your knowledge and experience.

I have a 2001 Td5, 250 000 km, no mods except 31" wheels and a 2" lift.

So to the problem: He runs great on 1st-3rd gear, a bit hesitation on high revs but that's another issue. In 4th, a whining (later almost screaming) noise starts building up with the revs. It continues through to 5th gear and culminates around 60 mph as a screaming high pitch sound. When i let of the accelerator it briefly stops, and de-acceleration is not as noisy. But as soon as I'm back on the accelerator the noise instantly returns. All gear changes are smooth except when I'm very quick between 1st and 2nd.

This is my search so far:
* I have run all gears with diff in neutral, no noise.
* Checked all fluids in axle and diff, the latter needed a small top up (leaks a few drops a day).
* Runs very smooth and straight in all speeds on paved road.
* There is a few degrees play in the prop-shaft, can also feel this while doing the kangaroo-test.
* LH front swivel housing is leaking slightly.

The noise is almost the same as when an old bus or coach is driving in high speeds, but with a more screaming touch. Makes me think of turbine sounds a bit.

That's it for now. Grateful for all answers.

All the best,
Fred

Sorry, forgot to write where I hear it. It's hard to locate and is heard all through the coupe, sometimes it feels like its coming from the engine bay, sometimes from underneath, hard to test externally since its only in higher speeds it develops.

Try changing the oil in the gearbox and transfer box.

After mine was remapped (?) it had a similar noise at higher speeds in fifth gear.
l changed the oil in the gearbox and the noise went away, never to return.

lightning said:

Try changing the oil in the gearbox and transfer box.

After mine was remapped (?) it had a similar noise at higher speeds in fifth gear.
l changed the oil in the gearbox and the noise went away, never to return.

Click to expand...

Thanks Lightning, Ill give that a try this weekend.

Hi, did you manage to resolve this issue, having a similar scenario myself and intrigued to know what people had to do.

I’m leaning towards the idea of it being a support bearing problem. No idea whether this may mean a complete new gearbox or rear housing off etc
Hope you got it sorted.

cheers Lyndon

My transmission was screaming in fifth gear at motorway speeds.
After changing the oil it's been fine, don't know what oil was in it but it seemed very thin.

Ah ok, interesting - thanks for the reply, may give this a go. But only just replaced all the oils

Warped exhaust manifold?

Thanks - going to a garage on Friday for a closer inspection. Hoping it’s not whole gearbox our job - but is what it is.
Lyndon