No second Gear

[Paul Down]

An interesting fault occured while driving to a car Trial on Saturday.

 

Second gear would not engage at all just as if something was blocking the selector rod. All other gears and OD fine.

 

Anyway drove 200 miles there and back without further problems apart from having to remember to bypass second. Removed the tunnel and it then appeared to select second OK, but nothing on the tunnel snagging it.

 

Took the top off the box today and cannot find anything obvious, Anyone any clues?

 

I dont really want to strip out all the selectors etc. unless absolutely necessary

[John Morrison]

Ouch,

 

Hi Paul,

That was exactly how box went when I had 'Lost' the input shaft cage bearing.

If you have the top off the box, rotate everything whilst fishing in the oil with a magnet

you will soonfind bits if its gone this way.

 

John.

 

See E-mail.

[Paul Down]

Thanks John,

 

I Did have a fish with a Frost magnet but found nothing, hopefully not that.

 

Will be in touch re Crypton when I have sorted out the tow car

 

Cheers

 

Paul

[LGFromage]

Maybe the second gear overdrive switch needs to be unscrewed a bit to make gear selection easier.

 

Tim

[Paul Down]

Thanks Tim, Genius!

 

That could well be the problem.

 

I stripped down the top having to drill out the selector bolts etc. and found absolutely nothing, would not even have thought of the 2nd gear switch as I limit OD to 3 and 4 but the switch is still in the top. Funny thing though when I had loosened off the top bolts it did select 2nd OK so your solution bears that out.

 

Good Man!

Edited April 12, 2014 by Paul Down

[Rodbr]

Hi Paul,

Hopefully that's it sorted out bit could you confirm if that was the problem when you are certain as it is one for the more obscure problems and fixes for the resto notes.

[Guest ntc]

I would go for tunnel cover or repro gaiter

[Paul Down]

Many thanks for all the suggestions but the mystery deepens.

 

Not the OD 2/3 switch Rod, it looked like the culprit as on closer inspection the switch had worn quite a deep depression in the top of the selector fork and it seemed conclusive. But:

I replaced the complete top with a spare TR2 one and when cold gear selection was a bit notchy but seemed OK. (the TR2 top had been lying around for 30 + years)

Took the car for a 6 mile run ( without the gearbox tunnel) and when warm I could not engage second gear again. . (Sorry Neil not tunnel or gaiter).

Even when it cooled down second was unobtainable.

 

Looking again at the gear cluster the second gear Synchro cone seems to be stopping engagement so looks like a box out job.

The car has only done 5000 easy miles since the previous fastidious owner had the box reconditioned. This is the second failure ( no pun intended) as the 1st gear countershaft lost a tooth a while back.

 

Perhaps I am being optimistic expecting a recon box to last a bit longer!

 

Paul

[AlanT]

I'd suggest that when this box was rebuilt the layshaft bearings were left alone.

There is a lot of fiddling about needed to do these.

 

The subsequent failures you are having may derive from this if the layshaft isn't running true.

 

Find someone who knows these boxes well. It is a DIY possibility but you need to be a good mechanic.

[Paul Down]

Thanks Alan,

 

It could well be a problem with the layshaft. The only curious thing is that no other symptoms are present, all other gears select easily and when driving for 200 miles no untoward noises or debris in the drained oil.

 

I replaced the layshaft bearings myself not long ago when the first gear sheared a tooth, as you say a bit fiddly but with a dummy shaft turned on the lathe, not too bad.

 

Once the box is on the bench, quite an interesting project. Its getting the thing out and even worse putting it back that is the pain.

 

To be continued..........

[AlanT]

If you fixed the layshaft yourself it should be OK.

Another candidate is the spigot and bush between the input shaft and mainshaft.

 

Putting it back is much easier with a trolley like I use.

https://www.flickr.com/gp/90670218@N04/eV75fL/

[Paul Down]

Alan, that trolley looks the business, it should make life a bit easier especially when mating back to the clutch etc. May have a go at knocking one up.

 

Thanks for the tip re spigot and bush, will report back when I have summoned up enough motivation to get the box out. The only way now to identify the problem is to crack open the box!

 

Grand kiddywinks here at the moment so busy blowing up bike tyres, fettling go carts etc.

[AlanT]

The trolley is low enough that you can slide it under the chassis.

 

Then you add the front and rear jacking screws and take the weight of the box.

 

If you leave these screws alone when the box is out then you just plonk the box back on and its at the right height to just slide up and into the clutch.

 

Just basic carpentry and hardware store metal to saw up.

[Paul Down]

After a bit of a struggle managed to get the box out. The clutch lever always seems to snag the floor and make life difficult to free it from the engine.

 

Still not sure of the problem yet but there is a fair amount of play on Second gear so that could well be the answer, yet to remove the awkward circlip and investigate further.

 

As they do, the 3 balls and springs shot out of the first synchro hub to hide in the workshop, but the interlock ball and plunger remains in situ is this normal?

 

What is the purpose of this interlock plunger ? From the diagrams, later boxs do not seem to have this interlock on the first synchro hub?

 

Cheers

 

Paul