Series 2a Gearbox makes clunking noise

[LachLandRover]

Recently my series 2a developed a clunking noise from the gearbox, but only in First and Reverse gear, the rest of the gears are fine. Can anyone help?

[djam1]

Recently my series 2a developed a clunking noise from the gearbox, but only in First and Reverse gear, the rest of the gears are fine. Can anyone help?

Whats a clunking noise we are talking about a crash box here.
If you engage 3rd then engage first or reverse does the problem go away?
Maybe you have a dragging clutch or is there excessive play in the drive line when you go from first to second?

Duane

[JDNSW]

Depends on what you mean by a clunking noise. I assume that you mean a repetitive clunk when driving steadily in first or reverse?

If this is the case, you have a damaged tooth on one of the gears shared by first and reverse but none of the other gears. This is a not unlikely event, as these gears are engaged by sliding gears rather than dog clutches like the other gears, so that the actual gears bear the brunt of any clashing when engaging gears. The only fix is to strip the box and replace the damaged gear, and presumably any other worn components, usually all bearings and seals at least, while you are at it.

On the other hand, depending how bad it is, it is very likely that it will go for years without getting worse, although there is the danger of damaging the meshing gear(s) which would then have to be replaced as well. As an immediate precaution, I would change the gearbox oil, both to have a look at what bits come out with it, should be at least a bit of a tooth, and to remove the possibility of the bit chipped off going through the mesh of some other gears and causing further damage.

John

[LachLandRover]

It is a repetitive clunk, it increases with an increase of rpm, and it started for no reason, there wasn't any load on the vehicle or a poor gear change.
I am going to drain the oil and see what I find. Does a chipped tooth really make a lot of noise or is there a possibility something could be wedged in between the teeth?

[JDNSW]

It is a repetitive clunk, it increases with an increase of rpm, and it started for no reason, there wasn't any load on the vehicle or a poor gear change.
I am going to drain the oil and see what I find. Does a chipped tooth really make a lot of noise or is there a possibility something could be wedged in between the teeth?

It is almost certainly a damaged gear tooth. If no poor gear change started it, it could be eitehr a crack was started by a poor change perhaps years ago, and a chip has finally fallen out, or there could be some foreign object that has gone through the gears and damaged them, possibly a synchromesh spring, although I associate this more with the Series 3 box, or a chip off a gear that has been loose in there for a while, or something that should never have been in the box in the first place. Something could have been there for a long time before getting caught in the gears. Certainly draining the oil (and seeing what you find) will be a good move. It is very unlikely that anything is caught in a gear - the shape means that anything between teeth is unlikely to be stuck there. On the bright side, it does not take much damage to make a very noticeable noise, and if it is a tooth marked by something going through the mesh, rather than a tooth chipped, it may even wear into being quieter.

John

[LachLandRover]

I have drained the oil and have found a few pieces of metal. I have also taken the top cover off the gearbox, I can see a few teeth damaged on the 1st speed layshaft gear. One tooth is half missing, a few have corners chipped off. I am guessing that the mainshaft gear teeth must miss the damaged tooth and hit the following one making a clunk. I am looking at removing the gearbox for repair.

[JDNSW]

I have drained the oil and have found a few pieces of metal. I have also taken the top cover off the gearbox, I can see a few teeth damaged on the 1st speed layshaft gear. One tooth is half missing, a few have corners chipped off. I am guessing that the mainshaft gear teeth must miss the damaged tooth and hit the following one making a clunk. I am looking at removing the gearbox for repair.

Yes, that is what I expected from the description, but you are never sure when you just have a description rather than hearing the noise yourself. Note when ordering parts that the suffix letter on the box serial number is all important. Also, I have heard that there are some substandard parts about, so be careful, although you may not have a lot of choice - I suspect that this gear is one that often needs replacement!

John

[LachLandRover]

I have a question regarding the removal of the gearbox, does the gear box and transfer box have to be removed as an entire unit as described in the manual or is it possible to first seperate the transfer box from the gearbox and then remove the gearbox by itself which would be a lot lighter and easier to maneuver out of the vehicle.

Lachlan

[JDNSW]

Yes, you can remove the transfer case first - likely to be messy (as in oil everywhere), but it is not that difficult. From memory there is one bolt inside the transfer case - if you don't have a workshop manual, get one before starting.

John