gearbox gears

Post by **alainmoran** » Sun Oct 07, 2007 10:28 pm

I remember reading in minor matters a while back that there were certain gears in the morris gearbox which have a tendency to wear out and that replacements are getting thin on the ground.

A good freind of mine restores lambrettas and recently had a gearbox made for him by a bloke in india, we got to chatting about the morris gearbox and my vauge recollection of the problematic cog, and he got to chatting to his contact in india who is now quite interested in fabbing them.

He would be looking at a run of around 300, but to get a price for them I'm going to need to get some idea of which gear it is, and ideally some drawings of the gear in question.

Post by **MoggyTech** » Mon Oct 08, 2007 2:14 am

Common failures are second gear, Laygear assembly, Layshaft and layshaft needle roller bearings. You will find photographs of the parts on the ESM parts website.

However, few people rebuild the gearboxes, as a good recon or second hand box is often easier (and in the case of 2nd hand cheaper).

There is also the consideration of worn synco rings and main bearings to consider. By far the commonest fault is jumping out of 2nd gear on the over-run, and that is down to worn syncro hubs as opposed to 2nd gear failure such as missing teeth.

Post by **steve4063** » Mon Oct 08, 2007 7:10 am

so is it hard to repair if it's jumping out of gear

i have a box thats jumps out of 3rd if you take your foot of the throttle.

Post by **bmcecosse** » Mon Oct 08, 2007 10:45 am

The little 'dog' teeth on the gears (2nd and 3rd) become worn each time someone 'crunches' the gear into place. This is what condemns the gear. New parts are available but expensive - I would wonder about the quality of parts from India! There are plenty of serviceable boxes still around.

Post by **Orkney** » Mon Oct 08, 2007 10:57 am

My advice for what its worth ....
steer well clear. Used to manufacture steel products in India in a very big way - sourced the steel from Tata which is the biggest supplier there.
Quality got lousy from them, even on BS Spec grades, as well as quality control being a MAJOR issue.
Only my opinion but i'd rather pay 10x the cost from a UK engineer who knew his stuff than trust the rest of the gearbox to one potentially sub standard part.

Post by **MoggyTech** » Mon Oct 08, 2007 1:44 pm

steve4063 wrote:so is it hard to repair if it's jumping out of gear

i have a box thats jumps out of 3rd if you take your foot of the throttle.

Unless you repair gearboxes on a fairly regular basis, they are not an easy job. The parts you should replace, often add up to more than a decent 2nd hand box. If you simply fit new gears and syncro hubs, you often get a very noisy gearbox due to changes in running clearances.

Obviously it's worth checking for the easy repairs, such as weak detent springs, loose shifter forks, but if gears and syncro hubs are shot, not nice.

Post by **steve4063** » Tue Oct 09, 2007 10:15 am

sorry to jump on this thread

all the gears were fine no crunching or anything the only think it did was seemed not to go into 3rd all the way and as soon as you let your foot off the gas it popped out.

1,2 + 4 were all fine just 3rd

Post by **bmcecosse** » Tue Oct 09, 2007 10:50 am

Well - could just be a detent ball is not present, or has benn inserted wrongly. But could also indicate loose/broken springs in the 3/4 syncro hub - but would expect that to show up in 4th as well. Well worth taking the side cover off - and check if the two little springs are present - and check if the 3/4 selector is tight on it's shaft.