Is there more strain on a gearbox when in gear and on "over run"

i.e just letting go off accelerator at high speed's

No. The same strains and stresses are happening, just in a different direction. Do you have a whine when you lift off the throttle?

no just a metallic. tat clat clat.

on drive it's a scraping noise.

that's why i asked if there's more strain on overun because the noise changes.

The gear teeth are being stressed on their other side on over run. Obviously changing down to the wrong gear at speed will put a lot of stress on a gearbox. The pinion crown wheel mesh especially is important so the shimming of the differential bearings are important. Any untoward noises from a gearbox need to be investigated. A look at drained oil would be a good start to see if there is metal in it although the internal magnet will catch a lot. My 5 speed became noisy after a clutch cable failure so I changed it back to my rebuilt 4 speed which doesn't make a noise ever. Regards Phil

i get it now. it's too late now what ever it is. I have a spare gearbox which I bought for £85. Just want this one to last until Christmas holiday.

The only thing is, the scraping noise magnifies ten fold just when the clutch touches flywheel. right on the point of contact. then when fully engaged goes quieter but still there obviously.

Can the torque vibration go through all the way to the output/differential in that short space of time. p.s wheel speed related

Edited 26 October, 201510 yr by damunk

Probably a silly question, but its not the clutch thats worn down and the rivets are just making contact with the flywheel when you do that? noticed any slippage at all?

I had the new clutch put in 12 month ago. Helix clutch. Ii thought it was at first that but reason I don't think that is because it's speed related.

Could also be the thrust bearing if it's a biting-point issue.

Well I know gearbox has gone because it's speed related noise. I'm taking the car in to have a new gearbox change. The guy who supplied me the gearbox left his release bearing on.

Are all release bearings compatible?

Looks like I've got two problems :)

p.s infact it can't be release bearing as it doesn't making it in neutral.. oh well. will soon find out.

Edited 4 November, 201510 yr by damunk

Gearbox change sorted it all out. thanks for help lads