Rebuilt gearbox

Evening, and happy Easter!

so, I have rebuilt my s111 gearbox, so new parts etc. back together with bellhousing and all looks ok.

on the bench, before reassembly, all selectors worked fine. Now assembled on bench, it’s very tricky to get first and second selector to engage, even with the gearstick reattached. Is this usual? Will it likely work with power through it?

I’m thinking the synchro rings are sticking…

any help appreciated, before I either dismantle it, or carry on and mate it to the transfer housing… cheers

If one selector is slightly in gear, you can't move the other.
If you've got a missing plunger for the interlock then you'll have a problem

Well done for that feat! , I know when I rebuilt mine and put it on engine without the props connected it was noisy which oh I read was normal until load was on as normal, in your case have you tried turning output shaft by hand as you try to change gear and checked that the selector forks are clamped in correct positions , in effect they should each slide back and forth fairly easily even without gearstick on

kermit_rr said:

If one selector is slightly in gear, you can't move the other.
If you've got a missing plunger for the interlock then you'll have a problem

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Thanks for that. The detents were all in the right places, and 3rd and 4th were selectable and also coming back to neutral was fine. And with the lid off, so no detents, 3rd 4th selector fork removed and selector loose, 1st 2nd very difficult using the rod or screwdrivers.

steve2286w said:

Well done for that feat! , I know when I rebuilt mine and put it on engine without the props connected it was noisy which oh I read was normal until load was on as normal, in your case have you tried turning output shaft by hand as you try to change gear and checked that the selector forks are clamped in correct positions , in effect they should each slide back and forth fairly easily even without gearstick on

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Yeah, turned output shaft by hand. And added old clutch plate to turn the input. A little tight in neutral, but does turn freely. Slight pressure in selector and is almost in gear 1st or 2nd, and only selectable into gear fully with some fiddling and helps to have reverse engaged to slide the hub.

You have put oil innit aintchya?

Col

Colthebrummie said:

You have put oil innit aintchya?

Col

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Erm…. Nope, it’d run owt the end…

However, do you think that’d make the difference? I would’ve thought it would go through the gears without… but I guess a new 1st/2nd hub might be quite stiff, so in oil would help/solve it.
Ta

Ok, I’m going to just crack on with building it up, and hope it works when there’s oil in it and power running through it. I have been able to get it into gear, just not easily. I’ll probably regret it and have to pull it out again, but even if I dismantle it now I’m not sure what I’d do differently. Wish me luck!

DeviousLandyGod said:

Ok, I’m going to just crack on with building it up, and hope it works when there’s oil in it and power running through it. I have been able to get it into gear, just not easily. I’ll probably regret it and have to pull it out again, but even if I dismantle it now I’m not sure what I’d do differently. Wish me luck!

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Good luck. Im sure it will be better with the oil in it and after it has been run in a little.

Col

Evening. So, I decide to bust into it again, dismantle, check, clean, swap out synchronisers, make a new gasket, rebuild, realise if fitted the reverse idler the wrong way around, turn it round, realise it was ok, turn it again, fit the selector rods and lid. And,…. Still the same.

I’m still convinced it should go into gear on the bench… shouldn’t it?!

I think you're over thinking it, especially as you can't obviously see anything wrong

I had a problem with mine when reassembling and there was a small tinny bearing at end in main gearbox case that got squashed by one of the shafts when I tried to fit the transfer box would not fit together, I thought there was something wrong at the two wouldn’t mate had to take it apart again to redo properly,
Sometimes it’s best to make sure and you get quicker redoing it, perhaps check each shaft slides ok by itself when temporarily fitted?

DeviousLandyGod said:

Evening. So, I decide to bust into it again, dismantle, check, clean, swap out synchronisers, make a new gasket, rebuild, realise if fitted the reverse idler the wrong way around, turn it round, realise it was ok, turn it again, fit the selector rods and lid. And,…. Still the same.

I’m still convinced it should go into gear on the bench… shouldn’t it?!

Click to expand...

Yes, it should, and whilst a squirt of oil on everything as you assemble helps, you certainly don't need to fill it to test it.

Any chance that the selector shaft springs and cross link slipped out of proper positions as you put them in?

boguing said:

Yes, it should, and whilst a squirt of oil on everything as you assemble helps, you certainly don't need to fill it to test it.

Any chance that the selector shaft springs and cross link slipped out of proper positions as you put them in?

Click to expand...

Thanks. Well, it’s ready to go back in, so I may as well crack on and see what happens now. I have already taken it apart again, and nothing seemed to be wrong, so fingers crossed…

Ok, so it’s back in. I can get all gears. It not easy on the drive, but seems to be getting easier. Changes between 1/2 and reverse are quite “notchy” and need “feel” to eventually engage at times. It was a lot better once the rear prop was on, providing some resistance to the output.

Ran well in situ, no leaks for now, overdrive works etc etc.

So, decision time. Do I button it all up and see if it improves with driving, or go straight for the selector and replace it. I paid £200 for thsis new one, so I expected better. Maybe it’s a reproduction one, sold as original.

Does anyone have experience of selectors improving following gearbox rebuild, with use. Seems unlikely, but maybe someone has some wisdom to share… I’d appreciate it!

Cheers

Have rebuilt a couple of gearbox's, usual for change to be a bit tight but not difficult. Can take a fair bit of time to free up. Change oil after 500 mls or so.

tottot said:

Have rebuilt a couple of gearbox's, usual for change to be a bit tight but not difficult. Can take a fair bit of time to free up. Change oil after 500 mls or so.

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I've done four series gearboxes and haven't had this problem, but four is a very small sample!

Thanks for the replies. I’m wondering if there a mix of gears 1 and 2 and the selector maybe not being suffix A. I have ordered the correct parts, but what if the selector is in fact for a later ‘box? Could this mean difficultly selecting?

Now it's in I'd just do 500 or so miles, see how it goes. If it doesn't ease up then strip and rebuild, testing it at every stage.

The parts book that I have shows that the only difference in selectors shafts and forks for suffix A and B is the reverse one, others unchanged.

There was changes in parts in the main gearbox not sure if any of this applies , but what new metal bits did you buy