406oc.co.uk

Hi guys,

Ive been struggling to get my HDI 110 into 1st gear, more so on these cold days, one morning when leaving for work, it would not go in, eventually after lifting clutch up and down and pushing into gear it did go.

Does anyone have any ideas what could be causing this?

Thanks.

Does it go in reverse without a fight? Yes - change the oil (1.9l 75W80), add some molydenum disulfide.
No - clutch isn't releasing.

Sumtimes have the problem in reverse, but not to the same extent. clutch was replaced by last owner, last yr.

Hmm, I take it it's better when it warms up too? If so then do the oil thing, maybe it's just straight 80 they put in it or something. Then it's clutch time...

Almost certain that it's the clutch hydraulics at fault.

Is your biting point near to the floor? If so, the clutch cylinder may not be pushing the operating rod far enough to give clean disengaging of the clutch.

Look at the slave cylinder on the gearbox, pull back the rubber cover on the cylinder and check for fluid around the operating rod.

Could be a faulty clutch of course, pressure plate springs damaged or spinner plate twisted.

Oil is a possibility, but is the problem recent or been happening for a while?

My previous Citreon would often refuse to go into reverse when cold, but I found putting into 4th, then reverse worked every time so I left it at at that. (I think it didn't like 1st either, but I always reversed out of garage). It's worth a try.

Depeds whether it makes an almighty crunch going in or if just won't go in to reverse. If the former the clutch isn't releasing, if the latter selecting another gear will turn the layshaft and you've got a better chance of the teeth lining up. Since I had my problems I've flushed my gearbox and put some additive in it, it's now easier to select all gears, not just third, so that's why I was suggesting it. I also hear it's usually the selctor forks that wear on the ML5T, not the synchronisers, so forcing it into gear isn't a good idea.

I can certainly say that my 2nd gear is not too happy in this cold weather so the oil does have a bearing on gearchange quality in my case but eases off as it warms up.

There is also a gearbox mounting that can cause gear selection trouble later in life on the 406 but usually at high miles/years.

My clutch bites near the top ! it doesnt crunch and its usually ok after its been driven for a while, i know there is an oil leak under the bonnet, not founmd out where tho, think its coming from top end, but everytime dipstick is checked that seems ok.

May change the oil and add an additive and see how it goes for now.


Thanks for all your help.

If 1st gear is hard to select and you can engage reverse without a crash - there is a problem with the syncromesh unit. If it were as a result of thick oil , dragging clutch etc. then it would crash in reverse because the mainshaft is turning. A good syncromesh would always slow the mainshaft down enough to allow the annulus to engage and most drivers will use this trick to engage reverse when the oil is thick on cold mornings. Try to engage with the engine stopped and let me know if it does or not and also try second gear as well. I might be able to tell you what's wrong with the syncro, the mainshaft or the 3 & 4th gear syncro.

Rite then, just tried it with engine off, went in 1st no probs, but wudnt go in 2nd first time round, so thats a new one!

OK - When the engine turns it turns the first motionshaft then the layshaft, the gears can only be selected when the interconnecting parts on the mainshaft
are free ie when each selector is in its neutral positions on the respective hubs. So for example if the 3rd or 4th gear hub annulus is somehow not clearing from the last engagement or the detent on that syncro is not holding it in the neutral position it will prevent another syncro from engaging ie first or second selecting ( these two are on the same syncro hub). Because the annulus teeth on each hub still needs to move the splines on the engaging gear to engage even though the baulk ring has stopped the gear turning, so if it can't do this it will not engage - other problems can cause the same result e.g. the gears run on needle roller bearings which have a habit of collapsing and jambing the shafts which can lock up the gear train. What happens when you switch off is the small oscillations in the engine stopping frees it off. You could try giving the gear lever a good shake across the gate just before you try engaging when it's running and let me know what happens. I'm sorry it's a bit complicated for a layman to follow if one does not know the layout. It is possible for linkage problems to do the same - internally this would be the fork on one of the selector shafts is working loose ( they are usually wired but who knows.) I'm assuming you can engage reverse without crashing the gears.

So my problems with third could actually be caused by 1&2 or 5th

Btw PSA gearboxes never seem to line up so all gears go in at the same time. Try this at home, with the engine off dip the clutch and select 1,2,3,4,5.

OK, so, clutch hydraulics seem ok, oil is next on the list, try a 75 grade oil, preferably semi synthetic, don't waste your money on the addative.

If all else fails, try selecting second gear at first, then select first before you move off, that can align the synchros.

jasper5 wrote:don't waste your money on the addative.

That's exactly what I always thought - snake oil. I only tried it as a last-ditch attempt to avoid loosing my car for a couple of weeks and spending a fortune having the 'box rebuilt. Molybdenum disulfide.