Fished out of my gearbox!

[Hawksfield]

Hi

You could also check the number of teeth on the Layshaft to ascertain ratio and which box it is if you feel it is not original

[Mick6186]

If you flush out the gearbox don't make the mistake I did. I removed the top cover from my 5 speed and seeing that the interior was a bit grubby I cleaned the interior with degreaser, put the top back on and stored it under my bench until needed( I am rebuilding a 1973130/5). Condensation must have formed in the box as I hadn't refilled with oil and when I came to fit the box I found the gearchange mechanism had seized solid. Upon inspection I discovered the selectors had a film of rust on and once moved seized where they went through the aluminium casing, so a strip down required. Silly me!!.
Mick

[john.p.clegg]

Mick

PM'd

John

[snowyelan]

There's really not much to the box, it's out, so most of the heavy lifting is done. My 13 year old son rebuilt mine (with supervision). I think the only special tools required are a set of circlip pliers and a rod that is a bit smaller than the idler shaft. You could use a piece of 3/4 wood dowel for the dummy shaft, it's just used to hold the needle rollers in place when installing the idler shaft. You might find the idler shaft is pitted, seems fairly common. The rest was fine on mine.

[davidj]

OK, you have convinced me. I have rebuilt triumph boxes in the past, this this design looks very similar. Cue lots of posts on gear box rebuild! As I mentioned, I believe the box is refurbished so I hope all the bearings etc are OK. Other than the idler shaft, does anyone else have any suggestions what to look for? It is just it is summer, the sun is out and I am very slow worker, so it will be autumn before I get it finished and the MOT will have run out!

[rgh0]

Pull it all apart and clean every component and the case in all the nooks and crannies.
check all the gears for nicks and chips or rough surfaces
replace all the bearings and needle rollers ( cheap and not worth the risk of not doing)
check the layshaft for wear at the needle bearings and tight fit in the case - the case can wear
check the synchro rings for wear
check the blocker bars for wear
check the selector forks for wear
check the tailshaft sleeve bearing for wear and the tailshaft running surface under the gearbox seal is not scored or worn.
check the welsh plug is firmly in place in the tailshaft nose that goes in the gearbox under the front UJ
replace the seals and gaskets
reassemble and it should be fine.
put in a magnetic drain plug if you dont have one
fill with good quality synthetic gear oil of your choice after you refit the tailshaft

cheers
Rohan

[davidj]

Thank you all for your help. I hope to make a start this weekend.

David

[davidj]

Good morning,

The gearbox is now disassembled and in bits waiting to be cleaned. It was just as well I took it apart, as while the components look OK, I did discover a lot of swarf in the oil.

However, I have one important question; the workshop manual, section F, section 24, mentions a "first gear bush locating ball", of which I could find no trace. Does anyone know if this was used on some gearboxes?

I am planning to change the bearings and seals of course. However, the synchro hubs look OK. What should I look for to see if they are worn? They still have cylindrical machined marks on the mating faces. Also, does the extension housing rear bearing bush wear? Does anyone know the size as I can get it measured with plug gauges at work. The lay shaft trust washes are badly scored so I guess need replacing as well.

Thanks in advance for any help. I am most intrigued by the first gear bush locating ball!

Cheers,

David

[rgh0]

The are two small balls that fit in holes in the main shaft and locate in a groove in the speedo drive gear and in the bush the first gear runs on to prevent them spinning on the main shaft. You can see them shown on the diagram of the gearbox internals on page 6 of section F in my manual.

cheers
Rohan

[Craven]

Hi,
?I am most intrigued by the first gear bush locating ball!?
Not used on later box, gear runs directly on mainshaft.
Rear bush is a special split white metal bush, are available.
Ron.

[davidj]

Thanks again. That may expain why I don't have a first gear bush locating ball! The only hole in the shaft is for the speedo drive.

Do the rear bushes normally wear?

David

[rgh0]

HI David
They do wear over time, I have replaced a couple when rebuilding gearboxes over the years. I cant remember the specific clearance dimensions on a new bush but it was only a few thou. If you can feel any free play of the drive shaft nose in the bush then I would fit a new one.

cheers
Rohan

[davidj]

I am now thinking about reassembling the gearbox, and doing a dummy run. In the workshop manual it states the synchroniser hubs, sleeves and main shaft are mated together, and assembly marks etched. However, I cannot find any! Will this be an issue? The components assembly fit together well with no obvious play.

Thanks in advance.

David

[Craven]

I think the only issue that has been noted on the etched marking is the sliding fit of the inner to outer hub. They seem to slide more easily in the correct marked position than just a random fit.
Ron.

[Hawksfield]

David

If you have the later gearbox you also do not have a nut and lock washer on the main shaft but a circlip, Make sure the internal peaks of the synchro cones are not worn with no flattening wear

Good luck on the rebuild