Leaky Five speed petrol Gearbox

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ashman
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Leaky Five speed petrol Gearbox

Post by ashman »

I have an oil leak from what looks to be the nose end gasket on my five speed petrol box.

Can this gasket be easily changed and is there anything to look out for when I remove the nose casing to change it? I don't want to disturb anything in there, so if anybody knows then all advice greatly appreciated.

Thanks

Ash

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Aidan
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Re: Leaky Five speed petrol Gearbox

Post by Aidan »

are you planning on doing it with box in the van ?
safer with the box on the floor stood on the bellhousing end, with 2x2 wooden supports for petrol boxes to keep the input shaft from touching the floor and most the oil will be in the bellhousing end
when you lift the cover off be aware the thrust washer for reverse idler and 1st gear may stick to the case/bearing and then fall out, nothing else should fall out - if doing it horizontally ie in the van then 1st gear may fall off as well with or without it's bearing, nothing else should fall out
anything else falling out says you have problems
clean the mating faces and degrease before fitting the gasket, maybe hylomar gasket to end case, put all the bits back in place then slide the end case on and retighten bolts 18Nm, or if corroded case (normal) tight enough to crush the corroded material below the washers and until nice and tight, to me there's a different feel between crushing corrosion and stripping threads but I do it all the time, but I only use a 150mm flex bar and am not very strong and have arthritis in my thumbs and weak wrists

ashman
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Re: Leaky Five speed petrol Gearbox

Post by ashman »

Aidan

You are a star.

Thank you very much for that in-depth explanation and I will be pulling the box out. I may as well change the noisy clutch release bearing while I'm under it - again!

Can you confirm that the gasket is very thin? It is probably correct, but the new one seems really thin and perhaps I expected something more substantial!

Thank you

Ash

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Aidan
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Re: Leaky Five speed petrol Gearbox

Post by Aidan »

gasket is thin :ok 0.15 or maybe 0.2mm thick

if doing it vertically no sealant needed to stick gasket to end case, put the gasket on the lower surface it will be located by the two dowels and stay put then put thrust washers in place on top of 1st gear and reverse idler if they have come out then lower end case on and tighten bolts, a slight wiggle will be needed to locate the three shafts that go into the end case, mainshaft, pinion shaft and the nylon guide supported 1st and reverse selector shaft

ashman
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Re: Leaky Five speed petrol Gearbox

Post by ashman »

Lovely stuff.

Thanks again

Ash

ashman
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Re: Leaky Five speed petrol Gearbox

Post by ashman »

Booked a couple of days off to drop the box and get it sorted - what is the saying 'I opened a can of worms'?

Unbolted and lifted the nose cover off and found loads of shrapnel inside! Various large pieces of shavings and seven (7) what look to be needles from a needle roller bearing that must be buried deep within the box! The inside of the nose cone is badly scored from all this loose shrapnel and the best bit was finding a needle from the bearing punched through the case near the suspected oil seal :-O I couldn't quite believe that could happen, but that at least explains where the oil was actually coming from :-)

Anyway, I think it is fair to say the box is in not very good health and either needs a rebuild or I am on the hunt for a second hand box - phooey!

Ash

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Aidan
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Re: Leaky Five speed petrol Gearbox

Post by Aidan »

sounds like usual 5 speed failure mode, worn pinion bearing allows shaft to move forward under load which compromises the space that 1st gear lives in causing wear to 1st gear and 1st reverse synchro hub and eventually bearing failure in 1st gear and the end case support/thrust bearing; the box has been poorly for a long time but lack of maintenance and regular oil changes to see the drainplug magnet to gauge the wear means that it has been driven until something has gone really wrong to get ones attention

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Mr Bean
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Re: Leaky Five speed petrol Gearbox

Post by Mr Bean »

By coincidence:
Having removed the WBX engine from my van exposing the five speed gearbox I was idly peering into the empty engine bay and noticed what appeared to be a dribble of oil from a bolt inside the bell housing to the lower left. I guess I need to check the torque. I did have to top up the gearbox a while ago and wonder if there is a connection here. I wonder if there could be a route from inside the gearbox to this point or has it trickled down from the rear of the engine? Must be more observant in future :roll:
Well-timed silence hath more eloquence than speech.
"A quiet shy boy who took little part in games or sport"
88 High top 2.1 WBX

ashman
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Re: Leaky Five speed petrol Gearbox

Post by ashman »

Aidan

In my defence, I did do an oil change on the box in 2016. The drain plug magnet didn't show any reason to be concerned and I was pleased at how little swarf there was on it. Between then and now it seems to have deteriorated rapidly.

Is it worth rebuilding and if so what would be the approximate cost please?

Ashley

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