Amazon: nut size

[Tail]

Morning chaps

I have lost reverse on my gearbox, got it out nothing seems to be out of the ordinary but i am going to put my spare box back in but the one i took out has the larger balancer on the end whereas the new one doesn't.

2 questions, one do i really need to swap these over and if i do what size is the nut, my 30mm is a fraction too big so i will need to go buy a socket and i would rather just buy it the once

Cheers Tail

[Tail]

Sorry meant to put pictures up of the nut i am talking about and the rear flange.

[Volvo_133]

Hi,
I am running an M41 overdrive box though I have a spare M40 box with the big flywheel type output flange, the nut looks identical to yours.
Tried metric sizes 30 is too big, 28 is too small, i dont have 29mm.
Tried AF size and found 1 and 1/8" to fit ok.

[Volvo_133]

Regarding the loss of reverse.
Select neutral, remove gearbox lid, find right hand side selector and try to push it with big screwdriver towards the rear. You may have to rotate your input flange to align/ mesh the teeth.
If this works ok, then the box is fault free. check the metal plate to the underside of the box lid has not broken and that the spring is intact and in place.

Also check the box lid top area where the gearlever alignment pins sit. These wear particularly the righthand side. If this is the case you may fix the problem by just fitting the other box lid.

[Tail]

Originally Posted by Volvo_133

Regarding the loss of reverse.
Select neutral, remove gearbox lid, find right hand side selector and try to push it with big screwdriver towards the rear. You may have to rotate your input flange to align/ mesh the teeth.
If this works ok, then the box is fault free. check the metal plate to the underside of the box lid has not broken and that the spring is intact and in place.

Also check the box lid top area where the gearlever alignment pins sit. These wear particularly the righthand side. If this is the case you may fix the problem by just fitting the other box lid.

Thanks the underside of the box lid looks ok, or at least it looks like the other box lid does, will try the selector tomorrow night, it was kind of self inflicted, the car had been sat a while and the clutch stuck, normally i just warm it up then switch off,select first then turn it over on the starter, didn't work this time so went back in reverse and there was a bang and not able to select reverse but looking in the box, everything looks to be the same in both boxes and nothing lying in the bottom.

[Tail]

Originally Posted by Volvo_133

Hi,
I am running an M41 overdrive box though I have a spare M40 box with the big flywheel type output flange, the nut looks identical to yours.
Tried metric sizes 30 is too big, 28 is too small, i dont have 29mm.
Tried AF size and found 1 and 1/8" to fit ok.

I have the same 30 and 28, might see if i can scrounge a 29 off someone at work, luckily my concrete plant was built so long ago all the nuts and bolts on it are AF so might have something there now that i know

[Volvo_133]

If you are able to select reverse by pushing the right hand selector to the rear, rotate the input shaft and check the output shaft rotates in the opposite direction. Rotate a few times listening and feeling for anything out of the ordinary. Now that you have explained how this occured, observe which brass selector fork is in operation, view down it and ensure that 1 of the fork prongs has not bent/twisted. My clutch rusts to the flywheel if not used regularly. I find it kinder in this situation to engage first or reverse, hand brake on hard, then attempt to start the engine with the clutch down.
Good luck.

[Tail]

Originally Posted by Volvo_133

I find it kinder in this situation to engage first or reverse, hand brake on hard, then attempt to start the engine with the clutch down.
Good luck.

Will try that method from now on, it seems easier than changing a gearbox

[Volvo_133]

Have you sorted the reverse gear issue now?

[Tail]

Originally Posted by Volvo_133

Have you sorted the reverse gear issue now?

Still working on it, been really busy at work, hopefully can have a look at some point today or tomorrow