Hi all! Looking for some help/opinions.

I have a T5 box mated to my cosworth YB turbo but have had to rebuild it numerous times as the syncros keep failing resulting in mainly not being able to select third gear. I am not sure why this keeps happening as running just under 300bhp, but it could be due to the exhaust crossing under the gearbox and overheating it.

Can anyone recommend a different box that might be more reliable? Or, does anyone know if I can get improved internals for the t5 so it stops happening?

All help appreciated!

Thanks

Matt

 

You can get I big tooth internals , quaife also do a t5 kit

 

thanks, will this solve the syncro issue do you think?

 

I’d watch a few videos from Paul before building it sounds like something is else is faulty

 

At upto stage 3 I had very little gearbox trouble 350 hp 2wds, I had one 3rd gear synchros issue but the box was just very old and tired once rebuilt by A1 gearboxes was never any bother again

Seems strange it keeps going makes me think there's a 3rd gear issue that's not getting properly resolved in the rebuilds

 

Paul the t5 specialist goes through problems with brand new synchros, all the new replacement parts are made by tremec who bought over borg Warner transmissions and it seems they make poor quality parts and allot of prep work needs done to new components before fitting them. New synchros can be too tight on the hub and need a light rub with emery ect and some even have burrs and dents

 

Thanks all for your help, really appreciated!

Thinking of sending it to CTS for rebuild unless anyone thinks that is a bad idea?

 

They did mine 400+ bhp in a escort mk2 without any problem

 

I had a cts big tooth box was great I couldn’t fault it

 

CTS did mine. Standard spec with good quality bearings. Doing it again I would pay the extra and go big tooth conversion as above.

 

Tbh a stock t5 should be ample for that power ,also depends what oil your using ,and also clutch,if your trying to do fast gear change from 2nd to 3rd maybe the clutch isn’t clearing quick enough,would have it stripped and inspected first

 

No.

If you are wrecking synchros, it's either clutch related, or driver related.

 

Thanks for this mate. The clutch is an AP 6 paddle but is quite old now so could be that. Is there anything you would suggest that could help?

If its driver related, what can I do to change?

Thanks

 

Age of clutch is irrelevant.

If the clutch is not releasing properly, it will be hard on synchros.

If the driver isn't using the clutch properly, or trying to ram gears too fast...it will be hard on the synchros.

Basically anything that is keeping the input shaft spinning when the clutch should be disengaged..will cause it to be hard on synchros.

Of course the other possibility is totally wrong oil.

 

Just running mobil atf220