Peugeot 406 Gearbox noise and shudder

[mark2256]

Hello All

I am new here and have a problem with my 2003 Peugeot 406 2.2Ltr Estate ex taxi with has 284000 miles on it but has been well maintained EBAY Purchase.
Purchased knowing it has a gearbox fault? It is fitted with the ML5C 5 speed gearbox does anyone know of any issues with this box. Mine seem to make a rumbling noise and if run with the front wheels off the ground seem to make the car shudder when the noise appears. There does not seem to be any problems with changing gears so syncros appear to be ok.

[CitroJim]

So the car is just nicely run in then

The ML5 is a generally tough old box of cogs. They do occasionally rattle at idle at high mileages but smooth out as soon as they're under way and at speed.

On yours it sounds like a bearing could be starting to wear, either in the diff or gearbox proper. Testing with the wheels off the ground is not particularly representative or informative as most cars will shudder under such conditions.

Is the noise only apparent at idle or can it be detected when under way? Does it get worse with increasing speed and is if so, does it go/change when the clutch is depressed? Is the noise related to road speed or engine speed.

Can you feel the shudder when under way?

Another possibility is the RH (long) driveshaft intermediate bearing is starting to wear and/or any of the driveshaft CV joints. The intermediate bearing is held in a housing attached to the back of the engine and can only be properly assessed by removing the driveshaft. Duff outer CV joints will click when on full-lock and duff/worn inners will tend to cause vibrations at certain speeds. From your initial description though, CV joints seem unlikely at first glance.

Wheel bearings too can make the noises you describe.

Sorry for all the questions

One good thing to do in any case is to give it an oil change as these 'boxes do occasionally take in water due to a quirk of their construction. You can't get at the drain/level plug very easily so drain and refill through the reversing light switch hole (after removing the switch!) with 1.8 litres of Total BV 75W/80 or equivalent oil. It is critical to use only a 75W/80 oil specifically formulated for Citroen/Peugeot gearboxes.

[mark2256]

Hi Jim

Thank you for the reply.

I have just finished looking under neath the car and it is covered in oil. It appears to be coming from the driveshaft oil seals. So I am going to replace these first then refill the box with new oil as per your suggestion.

[CitroJim]

You'll more than likely find the 'box is almost dry of oil Mark. Thing is, they'll soldier on for ages and ages with very low or no oil and only complain when put under heavy load like towing...

Here's hoping new seals and new oil does the trick

[mark2256]

Hi All

Have now started using this car after replacing drive shalf oil seals and refilling with new oil. All the gears select fine nice close ratio box up and down the gears. The noise only appears when driving and is there through all the gears it stays there even when the clutch is depressed. It also seems to get louder and fast as you speed up.

Can anyone help please.

[Peter.N.]

It maybe that a bearing has been damaged by lack of oil. Is the noise still there if you put it out of gear and coast? If it is the problem will likely be with the output or layshaft bearing, if it stops it will probably be the 1st motion shaft bearing which may be easier to replace.

Peter

[mark2256]

Hi Peter.N.

Thank you for the reply. I will try costing the car later today to see what happens and post the resault later today.

[mark2256]

Hi All

I have now tried coasting the car and the noise and chuntering still persist through all the gears however on turning right the noise seems to get louder.

[CitroJim]

That to me sounds like one or the other of the inner CV joints is worn rather than a gearbox problem.

[Peter.N.]

I would agree, or maybe even a wheel bearing or r/h shaft centre bearing. Are the shafts pushed right home into the diff?

Peter

[mark2256]

Hi all

Thank You for the replies

Further road testing show without the engine running and out of gear with or without the clutch depressed the noises still persist. I am also thinking wheel bearings, CV joints, Driveshaft intermediate bearing or diff bearings. Once the weather improves I will investigate further by stripping out the drive shafts.

Thank You

Mark

[mark2256]

Hi All

I have now tracked the noises to the gearbox. So need a replacement box I can find plenty of 2ltr boxes for the 406 but not many for the 2.2ltr. Can any one tell me if a 2ltr box will fit.

Thank You

[mark2256]

Hi All

Well I was Wrong in my diagnosis of this fault. It was the front near-side wheel bearing. Now changed and all noises have gone "Silence is Golden"

Thank You for all your Help.