Gearing up for a refurb

[silloyd]

OK, so some while back I acquired a spare gearbox for the princely sum of £35.22...including delivery....from Newcastle by Tyne

I have no history for the box so I need to check it out and decide whether it's fine as-is, needs a refurb or is only good for parts, so I come seeking wisdom

I took the side cover off at one point and the insides appeared to me to be in reasonable condition .... but I've never refurbed a gearbox before, so I can't really be considered to be a good judge!!

Before I go stripping the beastie down to it's most minute component, can someone please suggest a series of checks that I can carry out to determine:

1. whether it's useful
   1. as a unit; or
   2. only for parts
2. if (a)(i) applies, what I need to do to make it as good as new?

[bmcecosse]

Show us a picture in the side of the casing... You need to compare the dog teeth on 2nd gear - with the unworn teeth on 4th gear. And - try to look inside at the teeth on the 1st gear section of the laygear - are they chipped and broken?

[silloyd]

Four pics, hopefully in order of 1st to 4th gear selected:
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The teeth look pretty clean and un-worn to me. Views?

[bmcecosse]

Strangely - the dog teeth on 2nd gear look better than 3rd gear! So perhaps it was replaced some time in the past. Compare with the unworn teeth on 4th gear. So - they all look serviceable - now just a question of trying to look inside to see the teeth on 1st gear - and more importantly - the matching teeth on the laygear. But what I see in these pics, and if 1st gear looks ok - I would use that box.

[silloyd]

Some close ups...
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What's best to see how 1st and laygear look like? ...open up and remove? ...as per the Workshop Manual?

[katy]

Small inspection mirror?

[bmcecosse]

Bright light down inside and you may be able to see the teeth - then gently rotate the shafts to look all round.

[silloyd]

More pics (not easy to take photos inside!!):
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looks fairly good to me with the naked eye, though the light reflections make photographing hard and the pics don't necessarily show the innards to their best.

[bmcecosse]

You're not showing the first gear parts in these pics - it IS v difficult although should be possible with the eye - if not with a camera. The gears are 'straight cut' - you do show the reverse idler, which looks v slightly chipped - but nothing to worry about. I would use it as is !

[silloyd]

Sorry, but I'm confused. I though first gear was the second from the left in the first set of pictures, or are you referring to the corresponding cog on the layshaft?

[katy]

In the pictures, first gear is hidden underneath the brass selector on the LH side.

[silloyd]

In the pictures, first gear is hidden underneath the brass selector on the LH side.

So it can't be seen with the selector in any position?

[bmcecosse]

Not easily - but you may get a glimpse of the edge of it by looking at an angle into the depths of the box when 1st gear is selected.

[silloyd]

Still can't get a decent photo but to me the teeth on the gears look reasonable. There appears to be some play on the input shaft, i.e. I can wiggle it laterally, but I don't know if it's normal/within tollerance.

So, what next?

I'd rather only go to the effort of installing the box if it's going to be good and reliable and not knowing it's history bugs me slightly.

Am I safe to just replace the gaskets and the tailshaft oil seal or should I err on the side of caution and strip it to do a more comprehensive (and expensive!) overhaul to be on the safe side? (Half of me wants to try the latter for the challenge! )

One final thing, the remote housing seems to have a space for a reverse light switch, so this clearly was not originally a Minor gearbox. Anyone know what switch would be likely to fit, perhaps an MG, Sprite or even old Mini?

[bmcecosse]

Well - it will be a box from a Spridget! So it will have slightly better ratios - and better bearings. Use it 'as is' - no point changing gaskets - they won't leak. Tail shaft seal if you wish. Strip down the old box when it comes out !

[silloyd]

Ah, thanks hadn't appreciated that it was not a Minor box up to this point. Also tells me what reverse switch I need to get (I'd like to fit a reversing light at some point anyway).

Will probably replace the tailshaft seal.

Interesting point on the ratios.

[silloyd]

Decided to pull it apart.

Lay gear:
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...reverse idler:
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...and lay shaft:
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As you can see, a fair bit of wear on 1st and reverse, plus lay shaft is cream crackered. However, at £120+ for a new lay gear (22G1100) and £40+ for the idler (22G1114), I think I'll put new bearings and a new lay shaft in and go with it! ....unless someone knows of a cheaper source for Midget gearbox spares(?)

AFAIK the bearings are the same for a 1098 and a 1275, is that right?

[bmcecosse]

There's nothing wrong with that laygear...and the reverse idler is 'acceptable...just go with your layshaft plan - and possibly needle rollers in the laygear? More importantly - what does 2nd gear look like?

[silloyd]

Isn't 2nd visible on the previous photos? (Page 1 of this thread)

BTW - was planning to replace lay shaft, front and rear bearings, both lay gear/shaft needle bearings, and the needle bearing between first and third motion shafts for good measure.

[bmcecosse]

Hah! I had forgotten the earlier posts.... all good enough for further service I believe!