Gearbox Tips Please

[KevJ+2]

Hello all,
Although I have rebuilt approximately 20 engines in my time, I have today, stripped down my first gearbox. It's a four speed, and although it all 'seems' ok apart from a disintegrated input shaft bearing, I have no real idea what to look for in terms of wear. All the cogs have their teeth etc but is this just the obvious? I bought the car as a non-runner so no clues as to clonks or gear jumplng etc. Any advice would be welcome and I can post photos if necessary. Thanks - Kevin.

[miked]

Kevin,

I don' have much experience but can add this.

Watch out for the needle roller bearing between the first motion shaft and the main shaft. I have found a few with their cage broken. Especially if the input bearing has been moving about.
No doubt you have examined the lay shaft and its needles when stripping. I have seen needles badly corroded even though there was oil about.
I believe you have to make sure that the lay shaft is a good fit in the gear case or you need a new case? Others will know this better.
The selector forks are another. You can see the wear in the edges were they move the selector hubs about. I end up picking the best ones from a few boxes. Or you can have the filled back up and machined back to the original width.

Be aware of the through holes into the main gear case when putting the bell housing back up to it. Many have had leaks there. Sealant! Also look out for the blank in the end of the prop shaft yoke. These have been missing causing a big oil leak when jacked up.

Is the special breather bolt clear on the gear turret?
Be dead happy with the reverse light switch operation before it goes back as it is well trapped when in situ'.

May all be obvious?

Mike

[KevJ+2]

Thanks Mike, that's a lot to check and no, not too obvious
lt's hard so say how worn the forks are but the layshaft needles seem ok. The breather bolt is OK but the reverse switch is shot, I've just seen one sell on ebay for some ridiculous price - must be rare
I suppose to get the 40 needles back in, you need a dummy layshaft or is there another trick? - Kevin.

[Hawksfield]

Kev

Use a length of wood dowel

[gus]

LAyshaft needles will be replaced

synchros should have nice pointy tips and the interior taper should feel rough and look like a very fine thread. They are not crazy in price

If any gears are chipped they need replacement, but that is unusual

New synchros 120 bucks, bearings might be another hundred. thrust bearings etc.

if the gears are worn [the little dog house shapes I call them] are worn good used gear sets are around

Worst case i think you are into it for 500 bucks

god I hate the strings lifting re assembly trick

[Chancer]

Then just turn the box upside down!

[Elan45]

I have a dummy layshaft made of stock diameter steel rod, probably 3/4 inch. I too just turn the box upside down to engage the laygear. The 3rd-4th shift fork is probably the most consistently worn part.

Be especially careful to fit the layshaft as shown in the manual since the forward end is slightly larger to fit tighter in the gearcase bore. Be very careful. Don't force anything.

Roger

[Chancer]

Did loads of them in the period, laygear rollers i always replaced as they nearly always needed replacing, often the layshafts were grooved, back then on sales cars I would sometimes turn the shaft 180?

3rd/4th gear selector forks, they could often be refaced with bronze welding and filed back to within limits, they seemed to last longer after that.

Synchro baulk rings would either be diagnosed on driving or visually inspected as mentioned before, another way was to push them hard against the gear and measure the gap (material left to wear) with feeler blades.

I would always replace the 1st motion shaft/mainshaft roller bearing (forgotten the correct name) as these often went, rarely did I replace rear main bearings or input shaft bearings, I would check them visually and by spinning them once degreased.

Drive and over-run faces on the baulk ring pyramids on each gear (forgotten name again) would also come in for close inspection.

Most of the time the box was being repaired because of a known fault so I knew in advance what to replace, i didnt rebuild them for fun in those days

[KevJ+2]

Thank you all for your replies. Yes, my main problem is inspecting a box that I have never heard or felt and having no clue as to the 'level' of wear makes it a challenge. 500 bucks at the moment is even more of a challenge My engine rebuild without ancillaries is coming in at about ?1500 and my wife's eyebrows are starting to meet in the middle but it's good to hear about the obvious things to look for. Ps - Chancer, I wish I knew half of what you've forgotten Kevin

[Chancer]

I also wish that I knew half of what I have forgotten cos I didnt know much and only know half of that now!

For the last 9 years I have been communicating in another language whilst learning it at the same time, during that period I have lost so much of my English, if it wasnt for writing on forums it would be even worse.

Funny thing is some things are like riding a bike, you teach yourself to rebuild gearboxes the hard way as there is no-one to show you, no internet or youtube and you need the car to get to work on monday, you do the same job decades later for a hobby and it all comes back to you, even talking about it, why can I remember to turn the box upside down to engage the layshaft, rotate the tailhousing to remove it yet I cant recall if I put a new coffee pad in the machine 3 minutes ago!!!

[KevJ+2]

Ah Chancer, this sounds like an age related problem, a bit like the gearbox - all the cogs are turning but you know it's wearing out
If your coffee is too weak, then yes, you have forgotten the pad Kevin

[KevJ+2]

Today, I got a bit more brave and dismantled the doings further in the hope if finding the cause of two tiny bits of metal I found when originally draining the gearbox oil. In the photo you will see the broken off tiny bits and I am quite pleased with myself for finding the cause.
My next question is - where is the best place to buy all the synchro rings, inserts, needle rollers, bearings etc.? Also, the box is tagged 2821E - hopefully this 'should' in terms of ordering parts, be pre August '69 as the car is Dec.68 (any thought appreciated).
Thanks in advance - Kevin.

Broken inserts against workshop manual

[PeterK]

I got my 2000E rebuild kit (bearings, seals, gaskets, etc.) from Team DeVille
Chatted with the guy, seemed very knowledgeable, got a good price (no VAT when I bought) & quick delivery

Peter

[KevJ+2]

Thanks Peter, I've emailed them so fingers crossed.
Kevin

[twincamman]

I had the good fortune to place a magnet on the drain plug of the tranny so all the little bits and needle bearings sank to the bottom and stayed there as a result nothing ran through the gears as the tranny was slowly disassembling its self over a few thousand miles....recommeded..Ed