Gearbox locks in reverse

Discuss mechanical problems here.
Forum rules
By using this site, you agree to our rules. Please see: Terms of Use
Post Reply
Bnerli
Newbie
Posts: 3
Joined: Mon May 28, 2007 9:48 am
Location: Sweden
MMOC Member: No

Gearbox locks in reverse

Post by Bnerli »

I'm helping a friend of mine getting her -59 Minor on the road, and we've run into a problem. The gearbox locks in reverse, and I have to open it (the lid on the side) and use a screwdriver to push back the reverse gear. When the reverse is locked we can move the gear shifter back and forth, and when I look into the gearbox I can see that 3rd and 4th gear are engaged. I then push back the reverse gear with a screw driver and now all 4 gears and the reverse can be engaged and disengaged as it should.

I then put everything back in place, starts the car and reverse it out of the garage. Then I move the gear shifter out of reverse, but the reverse is still engaged and there is no way of getting the gear shifter "back into reverse" to be able to disengage the reverse. I then have to drain the oil, open the gearbox and use the screw driver again to disengage the reverse.

Why is everything working fine when I'm looking into the gearbox, but the minute I drive it the reverse locks up? The gearbox has been restored (put together from parts of 3 different gearboxes) by someone else, and he says it should work. The car has not been moving since last year, can it be that there is no lubrication left on the reverse gear axle and gear so that it does not move as smoothly as it should? Or has this guy forgot some part when he assembled the gearbox?

I hope someone has a hint for me, I have worked on old cars for 20 years now (but this is my first try on a Minor :D ), and I have never encountered this problem before.
bmcecosse
Minor Maniac
Posts: 46561
Joined: Wed Feb 16, 2005 11:24 pm
Location: ML9
MMOC Member: No

Post by bmcecosse »

He must have left out some of the interlocking plungers. Probably means a complete strip down to put them in. Just possible the reverse selector is loose - you can check that from the side cover - and are the two little springs and plungers present when you take the cover off ? These are not interlocking as such - but do hold the selector rods in place.
ImageImage
Image
Bnerli
Newbie
Posts: 3
Joined: Mon May 28, 2007 9:48 am
Location: Sweden
MMOC Member: No

Post by Bnerli »

Yes, the two little springs and plungers are present when I take the cover off. I'll take off the cover again tonight, I'll check the reverse selector then.
bmcecosse
Minor Maniac
Posts: 46561
Joined: Wed Feb 16, 2005 11:24 pm
Location: ML9
MMOC Member: No

Post by bmcecosse »

Sadly the interlocking plungers must be fed in as the selector shafts are fed in - if they have been missed then the I don't think it can be sorted with the box in the car.
You don't tell us where you are - but there is a cheap box on ebay at the moment - near Lincoln!
ImageImage
Image
Bnerli
Newbie
Posts: 3
Joined: Mon May 28, 2007 9:48 am
Location: Sweden
MMOC Member: No

Post by Bnerli »

Ok, thanks. I live in Sweden, so I'll have to try to work it out myself. I'll hopefully see tonight if the problem is that the interlocking plungers are missing, and if they are I'll have to take down the gear box anyway. To then take it apart anf fix it, or to get a replacement will be the same hassle, and with a replacement I may have to restore that...

Thanks anyway!
bmcecosse
Minor Maniac
Posts: 46561
Joined: Wed Feb 16, 2005 11:24 pm
Location: ML9
MMOC Member: No

Post by bmcecosse »

Study the workshop manual - it's quite tricky doing the plungers as I remember - but it's 40 years since I rebuilt a Minor gearbox!
ImageImage
Image
Post Reply