rebuilding a 4 speed manual gearbox

littleburner1 · Post by **littleburner1** » Tue Jul 31, 2012 11:20 pm

Hey guys so for the last few months my gearbox has snapped a tooth and sounds god aweful in 1st and reverse due to the fact there scynchonised. i got a spare gearbox with my marina only problem is im not sure how to check it and ive been quoted £100 to remove and refit the reconditioned one but i really wanna learn to rebuild the morris marina gearbox for experiance as i enjoy trying to do everything on a car.

ClaytonSpeed · Post by **ClaytonSpeed** » Wed Aug 01, 2012 8:05 am

Hi,

I've not rebuilt a manual box myself but I have uploaded the factory workshop manuals on the main site: index.php?option=com_jdownloads&Itemid= ... itstart=10

My dad had his 1.3 box reconditioned for around £200. He didn't fancy doing it himself. If you have a spare to practice on then go for it!

Ben

jiversteve · Post by **jiversteve** » Wed Aug 01, 2012 9:38 am

Jubileenut will be along in a while, but meantime here is an overview.

The basic gearbox is the same as a Triumph Dolomite and several other Triumphs so the good news is that many of the internal parts are readily available from Rimmer Brothers and other Triumph parts suppliers.

The difficulty as I understand it, is that the internal gearsets are unique to Marinas and they are rare.
There are also two different reverse idler gears, and you wont find out which one you need until you dismantle the box.

littleburner1 · Post by **littleburner1** » Wed Aug 01, 2012 10:50 am

thanks for that guys

so whats the best way to go about removing a gearbox without an hydrolic lift ?. just took at look at the site and with my marina being a 1275 block im not sure if it would be an early triumph gearbox or a late 1300 one also with my first and reverse sounding bad im not sure what i would need

Post by **MarinaCoupe** » Wed Aug 01, 2012 10:54 am

What has happened is that one or more teeth have been chipped or broken on the reverse idle gear. This is a non synchronised gear which turns the normal rotation of the gearbox into the opposite direction of output. People try and snatch reverse with too many revs on and don't try to let the gears match speed before dropping the clutch.

As Jiversteve says you'll have to at least partially dismantle the box to work out how many teeth your idle gear has. Try RimmerBros for a replacement or LeacyMG it's most likely the same as Triumph Dolomite or Spitfire 1500. The number of teeth vary by engine size and year of manufacture, there's no guaranteeing that your gearbox is original so the only way to be sure is to count the teeth.

Let us know how you get on.

You might want to start a topic on the Readers Cars section.

JubileeNut · Post by **JubileeNut** » Wed Aug 01, 2012 7:33 pm

Simple enough to do with some home made tools, but if the reverse idler has lost teeth you will need to inspect the lay gear and the outer syncro ring which mesh with it as they may have taken a hit as well.
To be honest to get a good idea of what is up you will have to strip it down and inspect all parts.

Good luck.

Coupedriver · Post by **Coupedriver** » Tue Aug 21, 2012 10:35 pm

Let me know if you can't find everything you need. I have a complete inventory.
Cheers,
Skip
marinaman@marinaman.org

Kiwi Ute · Post by **Kiwi Ute** » Thu Oct 20, 2016 8:15 pm

beniboyz wrote:Hi,

I've not rebuilt a manual box myself but I have uploaded the factory workshop manuals on the main site: index.php?option=com_jdownloads&Itemid= ... itstart=10

My dad had his 1.3 box reconditioned for around £200. He didn't fancy doing it himself. If you have a spare to practice on then go for it!

Ben

Hi, last night I backed into my driveway and when I moved the gearstick back into neutral it went all 'funny', it was all over the place and I think the gearbox is now stuck in a forward gear, in any event I cant't get neutral - or any other position and the gearstick is all 'sloppy' when you move it, you used to be able to feel it 'snick' into each gear. And having the motor running or not makes no difference

Any ideas what the problem is and also any idea why I can't get Bens link above to open?

BTW: This is the first issued I have ever had with the gearbox.

Post by **MarinaCoupe** » Thu Oct 20, 2016 8:44 pm

That will be the pin in the side of the gear selector stick ball.

There's no need to drop the gearbox out. If you can get the front carpet up, you can remove the plate that retains the rubber gaiter. Unscrew the the gearknob. Slip the gaiter and carpet off the gearstick.

You will see a cup that holds the gearstick into the gear selector housing, press it down and rotate it anti-clockwise wise and the cup will unlock, which will allow you to carefully remove the gearstick.

You will see a pin (or sometimes a roll pin) in the side of the ball at the bottom of the gearstick. If you check in the gear selector housing you will see a corresponding slot. The pin should ride in the slot. What happens is that the pin gets lose in the ball and then doesn't ride in the slot.

The fix is to degrease the pin and the gearstick and then either refit the pin with locktite, or fit a roll pin with a slightly larger diameter. Trial fit the gear selector and see if you can select all the gears, before refitting the rubber gaiter and carpet and gear knob.

Let us know how you get on.

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Post by **PHUQ** » Thu Oct 20, 2016 10:51 pm

Mine did exactly the same thing, it's what Chris said. Get the cover off and it's pretty self explanatory. I swapped the loose pin for a suitably sized roll pin, although just popping the loose pin back in will allow you to drive it. I shoved it back in and put a cable tie around the outside to hold it in to get me home!

Kiwi Ute · Post by **Kiwi Ute** » Fri Oct 21, 2016 12:10 am

Well thanks for the sound advice chap but I figured out the problem half an hour ago - there's an alloy fitting that the smaller (lower) ball on the gearstick fits into, this fitting is attached to a shaft that goes forwards into the gearbox proper (to the selectors).

The alloy fitting is secured to this shaft a a rolled-pin that goes through it and the shaft from left to right.

My rolled-pin has disintegrated totally and was lying in pieces in the bottom of the housing.

I cannot see how I can get access to the shaft to enable me to press in a new rolled-pin - any cunning ideas? Or do I need to remove and strip the whole gearbox to fit a $1:50 rolled-pin?

OH, and there was nothing covering the opening that gives access to the bottom of the gear-stick etc, (just above the drive-shaft flange).
My guess is there is meant to be a 'plug' of some sort that presses into the end of the housing to keep dirt etc out?

Kilroy · Post by **Kilroy** » Fri Oct 21, 2016 12:35 am

In my opinion, the Haynes manual gives a very good step-by-step procedure for stripping and reassembling the gearbox.

The only 'special' tool you really need is a dummy layshaft to fit inside the laygear cluster otherwise all the needle roller bearings drop out. I made one from something I had laying around. It needs to be shorter than the real one so that the gear assembly can drop inside the gearbox allowing the main cluster to be removed.

The first/reverse gear is obvious and presents no problem for removing and refitting.
The first motion shaft varies for either 1275 or 1798 engines. Item 7 in the included diagram. Must be correct for engine size or will not fit/work.
The synchronizer assemblies both contain 3 small springs - items 17 (#106388) and 28 (#104445) in the diagram - and they frequently break. This gives exactly the same symptoms as worn out synchro rings. I have never replaced a single synchro ring, but I have replaced some or all of these springs in every gearbox I have overhauled. Rimmers should have them.

While the laygear clusters are different for 1275 and 1798 engines, the amount of difference is negligible and would really only favour heavily loaded commercial vehicles.

There is a washer (item 49) inside the tailshaft housing that often remains in place when stripping. As long as you know where it is when reassembling - no problems...

Kiwi Ute · Post by **Kiwi Ute** » Fri Oct 21, 2016 12:55 am

Thank Kilroy but do I have to remove the gearbox and remove the plate that covers the selectors so I can take move the selector-shaft back far enough to get access to press/hammer in the rolled-pin that holds the fitting to the selector shaft?

Or is there an 'easier' way that I cannot think of??

Kilroy · Post by **Kilroy** » Fri Oct 21, 2016 7:59 am

Mate.
My reply was to the original poster.
Your problem could be really simple as replied to by several others already.
If it is just the gearlever itself that is the problem - not the gearbox - release the gearlever from inside the vehicle by lifting all floor coverings then undoing the spring loaded cover as you would a light bulb.
Fit a new pin in the ball part of the gearlever and refit it.
This is presuming we have your problem correctly diagnosed.
Sometimes the nylon socket at the lower end of the gearlever disintegrates - where it plugs into the end of the selector shaft - and sometimes the roll pin that attaches the outer socket to the selector shaft does the same. You need to describe carefully which pin has broken for us to give the right advice.
If it is the lower outer socket that has come adrift then the gearbox needs to come out of the vehicle for repairs to take place.

Post by **MarinaCoupe** » Fri Oct 21, 2016 8:31 am

Can you post some pics, it would help a lot.

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