SIII gearbox overhaul

[Ah Smithers]

Wow that lay shaft really is toast .....

You get 2nr Baulk Rings in the Legs Kit. (Part No FRC5931)

LR genuine parts are manuafactered (largly) by the same people. The reason LR Genuine Parts are so much more expensive is that they have to factor in their overheads and warrany. I have recently rebuilt my SIII gearbox and used non genuine parts with confidence. Looking at the wear on the layshaft it would be safe to assume that other components have some wear too. For the price of replacing the 1st 2nd syncro I'd do it. Belt and braces.

As a comparison have a look at the attached files they show my old 3rd/4th syncro (springs missing) and show the wear on the bronze millings and the dog treeth. The pricipal aim of opening the box was to place this unit. The old one makes quite a funky paper weight too

Have you checked the reverse idler gear? Put a bit of heat on the outside of the case. There's a small hole on the back of the lug supporting the other end of the idler shaft. With a narrow drift, knock it out form inside. It may be as well to have a closer just in case.

You'll get new main shaft bushes too from LEGS.

The only thing you do't get with this kit are the 2nr bearings for the constant gear (which you took out prior to splittting the boxes). Mine were very worn and at £4.50 each a bargain too.

Best of luck.

Keep us updated.

Cheers

Andy.

 

[peaklander]

Thanks AH - those pics on your site are really useful. I think at this stage I should also replace the 3/4th synchro - certainly the dog teeth on mine are as worn as on yours and the rings are almost the same.

I did take out the reverse shaft - see pics. The teeth are polished but I think not too much wear (although they are flat across the top?). When I rock the gear assy on the shaft there is slight movement. There is a small step at the line on the shaft where it goes into the casing - I guess that indicates the wear along the rest of it. Certainly the thrust washer and spacer are not a snug fit but that must be ok I think.

Thanks for the advice on replacement parts - I just hope they are OK. I heard bad things about cheaper brake cylinders and the like.

Anyway, need to make my shopping list.

Cheers

 

[CCKW353A1]

That reverse idler is a roller bearing one and it does have a step in the shaft as new. Its part of what holds the gear in mesh, the journal being slightly on the pi$$ to make the gear walk into gear.

 

[peaklander]

more pics of my s3 gearbox rebuild at www.log-rover.co.uk , Putting things together, page 9 'ish.

good luck..[/quote]


Hi Logrover- I think I failed to credit you for your photos - they are great and are helping a lot as I work out what to do.

 

[logrover]

you're welcome

it's surprising how useful i've found my pictures as well actually - refering back to them a couple of years later to see how i originally assembled something....

in particular, i have a problem with my reverse gear at the moment - keeps jumping out of reverse, so i was checking my pics recently. I had replaced the roller bearing and the shaft (as worn through the hardening), but reused the gear itself. I also had a new layshaft (had to be britpart i'm afraid as genuine was too expensive for that part). I've reset the selector forks so am confident its not those, so am thinking (hoping) its wear in the reverse gear teeth themselves. I now have a new genuine reverse gear, and will be going in again to replace that, as soon as i can find some downtime (it's a tad busy for firewood orders at the moment...).

I'll take some more pics when i get chance to get back into it.

 

[larryowner]

logrover thanks for the pics on gearbox rebuild very useful.I am at the moment rebuilding a series 3 suffix "D" box,that someone else srtipped. My problem is Im not sure witch way around to fit the 3rd/4th synchro hub on the main shaft. I see the spline in the centre of the hub is relieved at one end, can anyone tell me if this should be towards the 3rd gear or towards the primary shaft.thanks

 

[logrover]

logrover thanks for the pics on gearbox rebuild very useful.I am at the moment rebuilding a series 3 suffix "D" box,that someone else srtipped. My problem is Im not sure witch way around to fit the 3rd/4th synchro hub on the main shaft. I see the spline in the centre of the hub is relieved at one end, can anyone tell me if this should be towards the 3rd gear or towards the primary shaft.thanks

the green bible (get one) says: "...must be fitted with the recessed end of the inner member towards the third gear".

i wouldn't dream of rebuilding the box without the manual - how you setting tolerances and torquing things up ? or are you going to be posting quite a few questions

good luck.

 

[larryowner]

logrover thanks for your reply and yes your right, I do need to get a copy of the good book.

 

[logrover]

Thanks AH - those pics on your site are really useful. I think at this stage I should also replace the 3/4th synchro - certainly the dog teeth on mine are as worn as on yours and the rings are almost the same.

I did take out the reverse shaft - see pics. The teeth are polished but I think not too much wear (although they are flat across the top?). When I rock the gear assy on the shaft there is slight movement. There is a small step at the line on the shaft where it goes into the casing - I guess that indicates the wear along the rest of it. Certainly the thrust washer and spacer are not a snug fit but that must be ok I think.

Thanks for the advice on replacement parts - I just hope they are OK. I heard bad things about cheaper brake cylinders and the like.

Anyway, need to make my shopping list.

Cheers

i've just dug down into my gearbox again to fix a reverse gear that kept jumping out - i have updated my website with more pics including my shagged reverse gear alongside a new one ( see attachment). my boxes are back in now, but still to connect props etc before testing. but the old and new photos may help (reverse idler and the In/Out member).

 

[conkers]

Your website is a gem Logrover thanks for putting it together.

 

[peaklander]

I'm afraid that this thread went quiet because, due to work, I have failed to do anything significant on my landy for months. All I've done has been a little on the wiring loom and fixing the dash to my new 'modified-for-series' Defender bulkhead (last summer's task). Have made a new rear loom and threaded through the chassis - just getting to grips with soldered bullets. etc.

With a few spare hours now available I have ordered and received the parts needed to get the gearbox back together so I hope to update progress soon (and I've had another look at the comments on this thread especially Logrover's fantastic pics).

I am a bit miffed with the condition of the genuine / new 3/4 synchro that I ordered as part of the new gearbox parts delivery - it's covered in surface rust and full of muck and dust. I'll get a response from the supplier before possibly naming, but for about £80 it's poor. (see pics)

Hopefully more news over the next days...

 

[peaklander]

Removed the layshaft bearing outer from the main casing and replaced with new. Also removed the mainshaft housing, oil seal and bearing.

How important for the main bearing and housing is the Loctite 601 that's mentioned in the workshop manual? Only got threadlock at the moment but read-up on the 601 and it seems to be very specialist (and pricey) - presumably essential ... can anyone advise me please?

I'm not happy with the feel of the new layshaft bearing I've fitted to the new layshaft. In a trial fit into the new housing the shaft doesn't feel as smooth as the old one does if I try it in the new outer, but it was so tight getting it onto the shaft that I fear I won't be able to remove if I decide to try a second one - any hints aboout removing it?

Thank in advance

 

[secondjeremy]

A blowlamp is a handy tool when working on Land Rovers - many parts that should fit relatively easily but don't will respond to a little heat!

 

[peaklander]

Yes I'm aware of the advantage of heat - very useful isn't it.

I have removed the bearing from the layshaft and will try a genuine one instead. Had to break it apart and then was able to drive it back off the shaft using a small drift onto the lip. Have also removed the bearing outer from the casing.
The supplier is sending a better stored new genuine 3/4 clutch
Tonight I fitted new springs to the 1/2 synchro, reassembled with the original balls and slider blocks and am ready to reassemble the mainshaft with new 1 & 2 gears and cones.

 

[Snagger]

Double post edit.

 

[Snagger]

If it's the rear bearing you're talking about, then there was a fault. It should be a loose fit over the shaft, the rollers only being held tight against it when in their outer race. the rollers should be free to rattle slightly when not fully fitted to both race and shaft.

 

[peaklander]

HI Snagger, yes must be the rear but to be honest it's so long since I took it apart that I can't be sure! Anyway it was tight on the shaft and it didn't feel right. The old one on the old layshaft could be removed easily by hand.

Just received the expensive Loctite 603 - hope 10ml is enough!

Been reading all the grumbles about the blue box supplier - I have just returned a three position dashboard switch (lamps and blower) as the switch throw from bottom back to middle didn't feel right - (no click) Poor quality on electric parts too.

 

[Snagger]

The lay shaft bearing that has its separate race pressed into the gearbox case is the rear bearing. The front bearing is a complete unit and is pressed into the bell bousing.

Like I said, with the rear bearing in its race but not on the shaft, or on the shaft but not in its race, the rollers should be slightly loose and very easy to turn. If it's tight, it's faulty.

One other thing - when I helped Daz rebuild his gearbox with a LEGS supplied bearing kit, I found that the main shaft rear bearing was slightly different to standard. It was a sealed bearing (ie. had rubber discs covering the ball bearings so all that could be seen were the inner and outer races). This should help prevent the standard but unwanted oil migration from the gear box to the transfer box. However, it may be a good idea to remove the seal from the gear box side of the bearing to ensure it gets a good supply of oil - I'm sure the pre-packed grease inside the seals is sufficient, but continual spalsh lubrication of EP90 is a belt and braces approach.

 

[peaklander]

Yes, it's the rear. Sorry I didn't explain - it wasn't that the bearing was tight turning, just that the fit to the layshaft (bearing inner) was very tight and it needed help to go onto the shaft. Maybe I damaged it - but I don't think so. Then when I offered it into the new race in the case, leaving it 'hanging', it seemed to spin roughly and off centre. Just trying the old one back gave a much smoother turn.

It was that that made me nervous and start again with a new one that will hopefully arrive today.

 

[peaklander]

I'm in need of more advice please...this time 1/2 synchro outer member.

Have I got something wrong or is it excessive wear? I've put mine together with new springs only and when trying it on the mainshaft the selector doesn't really want to slide. I think that the blocks are intended to be prevented from moving too far by the synchro rings against them but the balls must move along the length of the mainshaft either way - is that right?

Problem is I can see some circular small intentations from the balls (not the grooves but small round dimples in the grooves )and I wonder if the balls are sitting in these and making it hard to slide out.

Perhaps someone could just explain exactly how it is supposed to work and I'll take a couple of photos to post

Thanks in advance...