406oc.co.uk

This is history for me now, but last year I was nearing the end of my weekly run home from Liverpool when I suddenly lost drive when I was on the motorway.
I was coming in to the 50mph limit stretch at the end of the M6. I changed down into fourth and all seemed ok. Tried 5th again, nothing, no rumble, grinding or squealing. Took it to my local garage and got a 2nd hand box fitted. They gave me my old box to play with, as I was interested to have a look inside. Lots of smelly oil, fairly clean and a lot of shrapnel. took off the end of the housing to find both the gears absolutely stripped clean.
I could find no evidence of anything else breaking, or coming loose.
I was just wondering if this is a known weakness. Is it likely to happen again? Is there any prevention?
It happened at just a tad over 100,000 miles.
I do a lot of Motorway miles, so the car is in 5th gear most of it's life.

I've not heard of this happening before. Thinking about it a slight manufacturing defect on one of the teeth causing it to break off could cause any other semi-meshed teeth to receive considerably more torque, knackering them too, and so on?

The two main gears are in constant mesh, engaged by moving another gear into mesh within the main box.
The failure was immediate, with no warning.
I am hoping it was a one-off defect and not something that is likely to happen again.

The bushes/bearings had no play in them, BTW.

You'd think one of the other would strip but both? As they say. sh!t happens...

I had a snap ring break inside the gearbox of my old KLE500, allowing the gears to move along the shaft and select 2 gears at a time. Fortunatly I was going in a straight line at the time...

As Victor Meldrew would lament - I don't belieeeeve it!
Approaching 120,000 miles, and it's happened again.

So that's less than 20k on my second gearbox and that has stripped 5th gear as well.

Anyone know someone at the factory who might be able to explain?
It's not like you can really abuse it once its in gear, so why is it so weak?????
My old rat-bag 405 saloon was a lot sturdier.

What flavour 406 have you got?

Sorry for the delay.
My car is a 2.0 HDi 'S' estate (90 ps)

I'm begining to wonder if that part of the box is being starved of oil.
I do long motorway trips, well 200 miles, every 4 days.
In 5th most of the way, seldom over 80 when overtaking.
Usually about 70-75 all the way.

Does seem unusual. I'm a relative newcomer myself. It seems gearbox failures are not unheard of, but don't seem common - not something we hear much about on the forum.

That's just plain odd, 406 boxes eating gears is almost unheard of, and yours has done it twice. I can't think of any external factor that could cause it, not bent drive shafts or owt. How about a shot in the dark - who looks after the oil? (Not to be insulting here but a Citroen franchise put the wrong gear oil in my second BX and I had to have the 'box rebuilt)

i have heard of an issue with a nut coming loose behind the extension cover which affects 5th gear, that was on the 110 box ml5 reverse by 1st.

Hi,
It my first time in this forum and I drive a 406 manual 97 down in Penang, Malaysia. I have had my fifth gear changed six months back because it was slipping. When they showed me the gear after removal it was all worn on the edge. I too had the same reaction from my mechanics ,as they have not had any experience of the a manual Pug box having this problem, but then again there are so little pug 406 manuals here, as the preference here all are for auto shifters. That was why i got so excited i found your forum. Any how Steve you may be right as the oil that came with the car manufacturer may say it is life time oil but the stuff that got drained out was sluggish and black. I could not find the approved oil here which was stated in my manual as from ESSO so I used ELF 75-85W gear oil instead; after the workshop changed the synchronizer and gear sprocket were changed. So far OK but the transmission sounds a bit harsh on the other lower gears in comparison now. What gear oils are used in UK?