Xantia - 5th gear problem

[Jaf]

Well I’m sort of glad it’s not a normal noise! Scared the life out of me on the motorway.

5th gear is engaging, at least a bit, as the car moves as the clutch pedal is partially released. The noise comes as the pedal is released further.

Still think it’s slightly possible that 5th gear is being pulled out of line by wonky engine mount or linkage. Going to disconnect gear selection linkage. (I don’t know the mounts are bad or I’d have changed them)

Should be alright to potter around in the car? No swarf in the gearbox to kill it...piccys in case I’m being dim.

[white exec]

Is the selector shaft actually moving it into gear?
Peter

Did wonder about that, which is why I suggested putting the box into 5th using the box-top levers, and not relying on the gearstick/cable/linkage.
Peter asks the right question.

Disconnect the external linkage, and then try engaging by hand.

[Jaf]

Hope to try that tomorrow. Too cold today.

[Jaf]

I’ve been driving around with just the 4 gears. Too cold/ windy/ rainy to work on it. I have popped into a couple more garages to check prices, between 200 and 350 labour to pop a secondhand gearbox and new clutch in. At this rate it’ll be April before I get round to doing it myself!

They all say it’s the gear itself. I still want to disconnect the gear lever to confirm it. Still tempted to just change the 5th gear and live with the heavy clutch for another 13 years!

Anyone know the official listed hours for changing the box?

[Jaf]

I’ve finally had chance to look at this again.

The selector rods on the gearbox all look fine. With the gearbox endplate off I can clearly see 5th gear engaging fully. I swapped the gear over from a secondhand gearbox but the fault remains. With 1 front wheel off the ground I can turn the wheel and see the engine turn over, after half a turn there’s a judder and graunch in the gearbox.

Any thoughts?

Thanks

[Jaf]

Oh by the way, don’t turn the engine over backwards. The auxiliary belt started to come off!

[Activa TCT]

Your gears look pretty chewed up with indents in middle.
For now, I see your options as, bad bearing which causes gear to jump out due to side torque.
Gear freely spinning on shaft.
Gear getting angled when you apply torque.
None of which is good but what can you do. I'd recommend getting another ML5 box from the wreckers. They are reasonably cheap.
Getting a bearing etc. replaced and shimming it can be a major pain.
Fix your release bearing too and clean the gearbox shaft and just replace the clutch.
It is hard and impossible to find out what's really wrong. Xantia's had problems with gear linkages that caused improper meshing of gears and tightening/putting strain on geartrain.
As said, if you remove the linkage, you should be at least able to put it in all gears. And yes, don't rotate engine backwards, timing belt is not made for that.

[Peter.N.]

Are you sure the gear is actually keyed to the shaft and not rotating independently? It does look a bit chewed up at the end. I always used to get a secondhand box for spare parts, new bits are expensive, there are probably some going for scrap - if you can find them.

Peter

[Jaf]

Just to confirm, I have already swapped the 5th gear from a second hand gearbox, with no change. The other gears are fine.

5th gear fully engages. No difference when engaging with gear lever or by hand, as seen when swapping the gears over.

I’ll try to take some clearer photos of the original gear tomorrow. It doesn’t look badly worn, at least it looks the same as the second hand gear.

So either I’m missing something, like the gear is not engaging when I believe it is...or the 5th gear shaft is damaged further into the gearbox.

[Peter.N.]

Is the gear actually turning the shaft round? I don't know how the drive is transmitted, presumably the synchro hub is splined to the shaft so the gear should lock into it when engaged. Did you change the synchro hub as well or did you notice any damage on it?

Peter

[Jaf]

I changed the whole lot, except the plain bearing as I thought that might be matched.

Some pics of the original gear. (There's a pic of the second hand gear in there somewhere but I'm lost as to which me it is - they look the same!)

I've ordered a clutch as it wants changing anyway. Going to disconnect the gear lever to make sure that the engine isn't pulling it out of gear. Thought I might take the gear plate off and watch what happens in 5th as it goes clunk.

[Activa TCT]

Basically what you are doing is, gears are always engaged (except reverse), you are just engaging and disengaging the sleeve that connects it to a shaft.
Check if the gear on reversing shaft doesn't rotate freely (the only shaft with fixed gears, they are press-fit.

download/file.php?id=19542&mode=view
Not sure if that inner part should be rotating, looks like it's welded. Or it's just me

[Jaf]

I’ve finally got around to getting the gear box out. Going ok so far. What’s with the plastic tray on the top of the gear box? Sigh. Will let you know how it goes.

[Jaf]

Gearbox is nearly out, just the RH driveshaft to move. I might have to give it a tap, I’ve soaked it in plusgas and am leaving it till Saturday. 1 of the gear linkages decided to leave the rubbery bit on the ball socket so I’ve ordered a new set from autodoc.

[Jaf]

I’ve not done much. Noticed that the clutch fork on the secondhand box is very, very tight. It won’t loosen up so I’ll get new bushes.