Lost 1st gear. Reverse on it's way out.

[esupergood]

Hello there
This is my first post. I've bought my first ever Moggy Thou and am enjoying it very much.
When I bought it I knew that the 1st gear was grinding and that I had to hold the gear stick in reverse or it would jump out.

That was about 6 weeks ago.

I've now lost 1st gear completely. It just jumps out straight away. But no big deal, it starts very nicely in 2nd.
Reverse feels like it is about to stop working any day. It grinds and stutters quite violently but just about does the job. Sometimes it doesn't engage and I have to drive forwards a bit and then try again, and then it works.

I was given a replacement gearbox with the car so I'm wondering... do I just drop in this "new" gearbox and expect all of my gearbox problems to disappear or else do I see about tweaking the existing gearbox?

I have almost zero mechanical experience but the previous owner has promised to help me do the work to get a working, smooth gearbox. He also has the manual and is a confident amateur mechanic. However, he asked me to post on here to hopefully get some ideas of the best approach.

Thanks very much for any advice offered.

Mark

[chrisryder]

welcome! what age is the car? and what engine has it got? (eg 948 or 1098). the 1098 and 948 gearboxes are different and not immediately interchangeable.

gearboxes are identifiable by external 'ribs' on the 1098 one, and a smooth case on the 948 one. if the one fitted, and the spare one you have are both smooth, or both ribbed, then you'll be ok and can swap them quite simply.

you could consider putting in the spare gearbox for a bit, to keep you mobile, and if it still isnt as smooth as you'd like, consider getting the gearbox you take out reconditioned. you can rebuild gearboxes yourself, but they can be fiddly, and easy to have springs fly accross a garage!

there is a guy on this forum with some rebuilt gearboxes for sale for £175, which is a reasonable price, as when i rebuilt mine i spent nearly that much on new bearings and other components.

click this link to his post: http://www.mmoc.org.uk/viewtopic.php?f=8&t=35200

[alex_holden]

I'm afraid no amount of tweaking will help when first/reverse gear is worn out (they share a gear which is why they both go at the same time). When mine developed the same fault, this is what I found when I dismantled it:


What happens is the teeth get gradually chipped away from 'crashing' into gear while the car is in motion, or from not pausing long enough between pressing the clutch and selecting first (tip: briefly touching 2nd, 3rd or 4th before selecting 1st avoids this pause).

As Chris says, it can be rebuilt but I would probably try out your spare box first, after taking the side cover off to have a look at the condition of the gears you can see (careful you don't lose the springs under the cover!). Alternatively £175 is indeed a very good price for a rebuilt box (if it has been done properly).

[bmcecosse]

As above really - changing the box is your only move -the old box will be uneconomic to repair. If your car has a 1098 engine - make sure the replacement box is of the ribbed type since the older smooth case boxes are weaker. Before you fit the new box - take the side cover off and look inside to assess it's condition - it's just possible to see the condition of the the gear teeth for first gear on the laygear - and the reverse gear idler. Also assess the condition of the dog-teeth on 2nd gear by comparing with the usually unworn teeth on 4th gear. They should all be nice and sharp - not worn down to stumps...........

[mike.perry]

If you are changing the box don't forget to inspect the clutch drive plate and thrust bearing. You do not want to be taking the box out again to change them in a few months time.