Noise in rebuilt gearbox

[don58van]

A fellow Minor enthusiast and I have just rebuilt a smoothcase gearbox with a good used laygear and new bearings.

It is back in the car and everything is working well, except for a bit of a 'crunch' when changing from first to second.

Any ideas on what this might be? I suppose it is likely to be a worn out synchro on second. What else could it be?

Cheers
Don

[MarkyB]

What oil have you got in it?

[bmcecosse]

It is indeed worn out syncro...just take time when making the change.

[don58van]

What oil have you got in it?

Engine oil 20-50.

I was hoping it was something other than a synchro. New 2nd gear synchros are a bit hard to come by
Thanks BMC

Don

[bmcecosse]

Aye - but as long as it's not jumping out you can live with it. I think someone had a method for renewing the the syncro surfaces on the early gears...? The original spec oil was SAE30 - so that '20' may be a bit thin -or you could try SAE 40 to see if it helps. The 20W50 will never reach it's '50' rating at gearbox temperatures.

[don58van]

I think someone had a method for renewing the the syncro surfaces on the early gears...?

Was that on here, Roy?

If anyone knows who or where, would they please let me know.

Down here in Oz, we don't have the luxury of plentiful ribcase gearboxes with their much improved synchros.

Don

[mike.perry]

Regard synchro as a luxury and double declutch up and down the box and it should last for years

[don58van]

Thanks for all the suggestions.
My fellow enthusiast with whom I rebuilt the gearbox now informs me that the noise isn't really when going into second, but when coming out of first.

Any thoughts on this?

Don

[mike.perry]

Still double de clutch!!

[bmcecosse]

Is the clutch free-ing completely?

[minor65]

I wouldn't necessarily call it a crunch, but a slight roughness will be felt went coming out of first when on the move. This is due to first gear not being a synchromesh gear. As long as its not crunching going into first or second, it will last you for years.