Gearbox: Removing the reverse gear shaft

[alainmoran]

The Haynes Book of Lies states that you can unscrew the reverse gear shaft 'while pushing it into the gearbox' ... so far all I've managed to do is chip the corner off it.

Does anyone have any tips for getting this part out ... also I'm concerned about attempting to reassemble the box with only the book of lies to go by (the workshop manual doesnt actually describe the 1098 gearbox, it has the previous version and the descriptions aren't that great)

Similar issues I'm having is getting the first drive shaft out of the front of the box, I have the shaft & bearing free, however there is a gear on the back edge of the shaft which prevents it coming out the hole which in turn is preventing me getting the layshaft out.

[alex_holden]

I vaguely recall that it's not possible to get the input shaft out through the front of the casing (I dismantled an old box to salvage the shaft so that I could use it as a clutch alignment tool).

[katy]

Did you remove the locking bolt that holds the reverse gear shaft in place?

[alainmoran]

Locking bolt?????

I guess that would be the 7/16ths bolt still in the underside of the gearbox directly underneath the back end of the reverse gear shaft!

You star .... this is why I love this forum

To get the input shaft out then I assume I need to do something with the tab-washer and the nut that's bigger than any of my spanners :s

[alainmoran]

So I've removed the circlip around the first gear shaft bearing, tried driving it back and it catches against the layshaft ... I've peened back the locking tab, but I'm shugared if I can get the nut to move - although I'm gingerly using sub-standard tools aka: pipe grips

[bmcecosse]

Many years since I played with these boxes (and my memory is mixed up with working on Mini boxes which are similar, but not exactly the same) - but I think you remove the layshaft and perhaps let the laygear drop inside the box...... The first motion shaft and gear may have to come out last, and go in first - after the third motion shaft. Why are you taking the thing to bits ??

[les]

You are right, the layshaft has to be removed to let the gear drop, then remove the 3rd motion shaft complete with the large housing then the 1st motion shaft should come out.

[alainmoran]

The 3rd motion shaft is out, as is the layshaft, however the bearing on the 1st motion shaft catches against the laygear as I try to drive it out ... I'll give it another go though, perhaps if I try to push the laygear aside while I am driving the 1st motion shaft into the box I will be able to get it out, but having a feel about inside that doesn't seem like it's going to work :s

I'm taking it apart because it made some VERY nasty noises in fourth gear at about 40mph, so I took it out and when I drained the oil I found CHUNKS of metal in the magnetic sump plug.

I think that bearings are stuffed - you can wiggle the 1st & 3rd shaft in their sockets ... which does not seem right. And the gear at the end of the 1st motion shaft doesn't look too clever so I need to get it out to have a proper look at it.

Either which way I'm going to need to go buy a spanner to fit those nuts ... and get this .. are you sitting comfortably ... Halfrauds is actually cheaper than my local engineering suppliers/factors ... I almost feinted!

[bmcecosse]

While this is all very interesting........ are you sure it's all worth the effort? Boxes are often cheap on ebay!

[alainmoran]

If my reaction to a problem was to just replace the whole thing and chuck the original away then I would own a modern car - most likely a Hyundai Coupe (I like the styling)

However it's not, one of the main reasons I own a Morris is because it CAN be fixed, and at this point in my life I enjoy the process of fixing it ... yes I probably am a bit weird, but hey!

Besides I have a two spare gearboxes already - although admittedly one is 120 miles away & until the ones I have up here are in a condition for me to go get it I only have the one spare available, which is the one I'm rebuilding ;)

I took this one out originally it out because it was making horrible noises and I'm reconditioning it now because my diff died and I'm currently running with the spare gearbox which has a dodgy third gear.

Also I am pretty sure that the diff dieing will have strained the already on it's last legs spare, so I want to replace both as a pair so that one doesnt cause undue wear on the other, I can then recondition the diff & box I'm taking off to give me known-good spares that I can just swap out when needs be (when I'm older and don't care so much for working on cars)

[bmcecosse]

Well - I do understand to a certain extent - but when you get in there - the cost of the replacement parts may outstrip the 'worth' of the box. But - no harm in stripping it down, and then doing the sums! I assume you have the selector rods and forks all out of the way already? Does the laygear not just lift out once the shaft is removed ?

[alainmoran]

After lying the box on the side, with one lip of the bellhousing in the vice I was able to knock the first motion shaft back into the box without the bearing fouling the laygear

Yes it would probably be cheaper to buy another 2nd hand box and run it into the ground. However my experience of morris gearboxes so-far is that pretty much all of them have stuffed drive bearings.

This results in the 3rd motion shaft waggling about when driven, which in turn results in the oil seal failing after a few hundred miles, which in turn generates an oil leak from the back end of the gearbox, which then leaves me peeling back the carpet and filling the gearbox with oil all the time.

Or worse, forgetting to fill the gearbox with oil, and driving 200 miles with no oil in it resulting in it making horrible noises and me having to swap it out for the dodgy spare gearbox which I removed because it has a habit of hopping out of gear but seemed to work OK until I forgot to fill the diff with oil (it's oil seal was stuffed too, for much the same reason) & drove to manchester and back on the motorway, at which point it too started making horrible noises.

So my plan is to create a gearbox & diff that I *know* to be good, and then I wont have to keep replacing oil seals or refilling them with oil ... it may seem like I'm making life hard for myself but in the long run I'm taking the lazy man's option ;)

[bmcecosse]

There is no oil seal on the 3rd motion shaft - just the tail seal which runs on the prop shaft....... By and large - the bearings will go on for ever, provided they are never run without oil!

[alainmoran]

I was told by a reputable source* that the most common reason for repeated failure of the oil seal at the junction between the 3rd motion shaft & the prop-shaft is down to the 3rd motion shaft bearings allowing the 3rd motion shaft to waggle about, stretching the oil seal and allowing oil to leak out the back end.

* an older gentleman who has spent most his life (from the early 1960's onwards) fixing cars for a living.

After seeing the amount of play in my 3rd motion shaft I can see that he was probably right! I don't know if the gearbox was ever run low on oil before I got it, so I can't say if that's the root cause of the problem (the gearbox has always chewed it's way through oil seals), however replacing the bearing seems like a good solution, especially since they are only a tenner!

[bmcecosse]

The 1st and 3rd motion shafts support each other - through the bush item 57. If it's worn - they can wobble, but normally the ball bearings are very long lasting. Tail shaft seal problems are usually down to problems in the prop shaft!

[alainmoran]

Ick ... don't say that .. I had a go at stripping down a prop-shaft & I ended up with needle rollers EVERYWHERE!