Borked gearbox 2...

If you look at the pic though, I'm not convinced that the hole goes into the gearbox. It may just have compromised the thread.


few pics of the other side to convince u
https://www.micra.org.uk/threads/pollymobiles-rebuild.35251/page-44#post-502714

dsc05675-jpg.36759
dsc05676-jpg.36754


imho I'd get another gearbox for afew reasons:
- when the clutch blew a hole in the casing whilst still driving under load and gear oil gushing out all over the bellhousing & underside,
the very low oil level could've caused some damage to the gear teeths or bearings.

- piercing the casing would've introduced metal & dirt debris inside the gearbox. no amount of filling & draining will get all of the bits out without disassembly.

- the casing is Alu and requires TIG welding, which is more difficult, time & labour intensive so could be more expensive

- TIG requires absolute cleaniness to weld properly so the gearbox must be disassembled & degreased otherwise u risk a faulty leaky weld and get weld spatter all inside the precision gear mechanisms

- epoxy sealing putty stuff also requires absolute cleaniness/degreasing to bond properly or else it'll just leak oil again and fall out later. imo not worth the hassle or rebuying all that oil again.
 
Cheers for all the input guys!

@frank, yep, my car's a '98 facelift. Were all those holes in your gearbox for lightness?!

I have access to a MIG welder. Could I just blob on some solder and file it back? Would that still fix mechanically to the hole? I don't know very much about welding... but it only really needs to be an oil-proof plug, so not that strong? I guess if it's just into a bolt-thread it doesn't really need welding up...

Is the hole actually into one of the bolt holes that connects the gearbox to the bellhousing? Quite hard to orient yourself in those photos without the box itself infront of you! It still looks the most likely suspect for the oil draining out, if it isn't the input seal.

I know what you mean about the risks of the particles damaging the gears, but the car ran fine until I parked it (!) with no graunching or whining. When I started it to move it into the shed, the gears engaged sweetly as ever. Any fragments would probably be quite small (given how the hole was 'pecked through' by the pressure strap) and may have even be flushed out by the torrent of oil that presumably gushed forth from the breech.

Maybe that's wishful thinking!

It'll be the weekend before I get another chance to look at it. Probably pick up a crankseal on my way home from work on Friday!
 
Just been studying your link pollyp and staring at pictures of your gearbox (!!) - the hole does go through into a recess formed in the bellhousing for the selector mechanism, doesn't it? So I guess this hole IS where the oil came from...
 
Just been studying your link pollyp and staring at pictures of your gearbox (!!) - the hole does go through into a recess formed in the bellhousing for the selector mechanism, doesn't it? So I guess this hole IS where the oil came from...
yes it is neil, best to source another 98 to 2000 1.0 g/box really
 
Hmmm...

I'm tempted by jbwelding the hole. A quick Google shows I wouldn't be the first to fix a gearbox case this way. Apparently degreasing is the most critical thing. If I open the case, I can access both sides of the hole and ensure the epoxy reaches through, let it cure and file it back...

Any advice on degreasing? Should I clean up the hole first, or leave it rough for a better key?

I know this is possibly a bit sketchier than replacing the box, but I don't have time to disappear off, faffing about in junkyards...
 
We use these at work. I find them almost indestructible.
They stick to almost anything.
The bottom one is made by Anixter as you can't see it in the pic.
 
I would personally say solder/weld the small hole. New clutch. Flush the gearbox as best you can. Back together and then sorted.

If you hear the gearbox bearings start to whine or any nasty noises then change it.

But it depends on your circumstances of course such as alternative transport if it breaks/friends to tow you home.

Really your choice bud. Btw interesting read overall!
 
Thanks for the recommendation! Any idea where I can pick up those metal expoxies at 6pm on a Friday?

How's quik steel? I know can I get that in Halfords... Would I be right in thinking JB weld would be too liquid and difficult to work in that situation?

No offence for seeming to ignore advice for a new 'box, all help is welcome and really appreciated - ideally I would get a new box, but I really need a THIS weekend fix!

Neil
 
Hey Neil. I've used chemical metal before on my micra build. That was when I made a plug for the dizzy drive out of the old dizzy drive.

That works fine but was a bit liquid until it started to go off.
 
Thanks for the recommendation! Any idea where I can pick up those metal expoxies at 6pm on a Friday?

How's quik steel? I know can I get that in Halfords... Would I be right in thinking JB weld would be too liquid and difficult to work in that situation?

No offence for seeming to ignore advice for a new 'box, all help is welcome and really appreciated - ideally I would get a new box, but I really need a THIS weekend fix!

Neil
You'd have to order these online most probably as we get them for the aircraft via 3rd parties. They're both putties like plasticine. I'm sure other metal putties will be similar.
 
Well, the gearbox is back on, but I've still to refit driveshafts etc. Another weekend...

Getting the box back on was quite a sod - took three of us three goes to do!

I bought a LUK clutch from Eurocarparts online, but was presented with a Valeo clutch in store. I accepted it as a Valeo is a decent enough make, but when installing it, the Valeo clutch clearly wasn't quite the quality of the OEM LUK part.

I bought Evo-Stik Hard & Fast epoxy putty in the end, as it was available from Halfords. (Eurocarparts had decided to cash-up before closing time on Friday so I couldn't buy anything, bloody workshies). The epoxy seemed to work pretty well - we let it cure for at least 24 hours, and the sample we left to cure off the gearbox was hard enough that it could be scratched but not really dented with a screwdriver, so I'm fairly sure it's up to sealing the gearbox.

I'll report back when I've got it all back together and the 'box full of oil, with a drip tray underneath!

Thanks for the help so far!
 
Put some new gearbox driveshaft seals on as well, if you haven't already. I didn't and one leaked so ended up farting around dropping the oil again. They're only about £6 each from Nissan.
 
Lever them out with a large screwdriver carefully. Push fit the new ones in. I got them started using my thumbs then used a big socket to seat them fully. Careful with the new ones. They have a line of thick grease inside.
 
Hey guys - thought I'd give you a little update.

Car's back on the road now - took an extra couple of weekends faffing about finding the time to finish bits and I wanted to properly underseal the new crossmember I put on last year.

Car was on axle stands for a couple of weeks after the ' box was reinstalled and no oil spots started to appear, so we'll see if everything holds together after it's had a few more miles put on it.

Car drives very sweetly - sweeter than I remember. This humble litte car really is worth fighting for! Gears swap as sweetly as ever. Only problem is I've clearly misconnected the speedo as it's not working - but that should be fairly straightforward to check when I get the chance.

Cheers for all the help everyone!!
 
Malfunctioning speedo turned out to be simply a loose connection - stuck hand down into the engine bay and gave it a wiggle, and it came back to life. Nice n' easy!

So far, no dripping oil either.

Thought I might share my 'repair' photos too:

Before:


And After:


Probably not the most beautiful repair, but it seemed to set pretty damn hard and so far there's be no dripping. Car's only done a few couple-of-mile non-essential test runs so far, but it'll get a couple of proper journeys in this week.

I'll keep you posted ;)
 
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