Ford BC5 gearbox slipping out of 5th gear.

[John Woodward]

My Quantum2+2 (Ford XR2 based kit car) has recently started slipping out of 5th. gear, but only when I back off the power, if I lightly hold it in 5th. it stays in. I have checked the gearchange linkage by removing it and resetting it and it appears to be OK. having read many different threads regarding the BC5 gearbox, I'm beginning to think it may be the 5th. gear selector clamp may need slight adjustment. I'm trying to avoid replacing or even removing the gearbox, so looking for something easy to try.
Any ideas ?

 

[grogee]

I don't know how different IB5 gearbox is to yours (all Pumas use IB5 AFAIK) so not sure how relevant our info is.

But I had a Suzuki that popped out of 5th. Slightly different to yours in that it would do it with slight power on ie cruising.

Diagnosed as worn synchro and repaired at great expense. The car was a POS anyway so don't know why I bothered!

 

[John Woodward]

Thanks for the reply. As far as I understand, the IB5 box was a development of the BC5 box and IB5's can replace the BC5 some early IB5 boxes had cable (as my BC5 has) instead of hydraulic clutch, as we have on our Puma, later Fiesta's etc. used cable gear change, but still the IB5 box.
Mine doesn't do it all the time , which is why I'm hoping it may just be an adjustment.
Incidentally the older Haynes manual, tells you how to dismantle and reassemble the gearbox, the later manual says to consult a specialist.