Technical 4th Gear? What 4th Gear?

[BikeDoc]

My Wife came home from work a couple of weeks back, saying the Multi wouldn't go into fourth.
Having already seen the guide here . . . 4th gear problem . . . I knew what the problem was, and took it round the block to see for myself.
Went into fourth first time, but I could feel it was a bit 'reluctant', was fine after that.
Pretty-much forgot about it until it happened again a couple of days ago, so today I whipped the end cover off.
Not much in the way of c**p in there, but given the tight tolerances involved in a gearbox, it wouldn't take much I guess.

Guide was spot-on, it's a very simple job.

Only thing I'd say is that you don't need to drain the oil via the drain plug before you whip the cover off.
Just stick your drain tray underneath and remove the cover.

 

[boilermansab]

How do you get the oil back in?
I've found it really awkward

 

[slobo]

Mine has lost 4th twice now.
I must say, of all the gears to lose, 4th is the least inconvenient, the Multi drives fine without it.
Every time I say I'll whip the end plate off at the weekend. And 4th comes back on the Thursday or Friday.

 

[hastingsmum]

Mine has lost 4th twice now.
I must say, of all the gears to lose, 4th is the least inconvenient, the Multi drives fine without it.

I drove my 1.6 Multi a whole summer with 4th coming and going, lol. and then when it got colder it was all fine again

 

[BikeDoc]

How do you get the oil back in?
I've found it really awkward

I bought a 1lt bottle (plastic) of gear oil ages ago, one with a pull-out plastic spout on it.
I just refill that from the 4lt tub of oil I have, stick the end of the spout in the level hole (filler plug is seized and rounded off) and squeeze, no need to have the bottle above the hole.
It's fine for topping-up, if you were re-filling from empty you'd need to refill the bottle a couple of times I guess.

Another option I've used is a large plastic syringe, and a short length of plastic hose that fits on the syringe nozzle.

I didn't get much oil come out, I jacked the left side (at the wishbone mount on the subframe) up a bit so most of the oil would run over to the right of the box.

 

[chr1s]

Is there a similar problem with 3rd gear ?

On Wednesday morning, I couldn't select 3rd gear for the first few miles, but all other gears were fine. Then, after a few miles, it went back to normal and has been fine ever since (over 450 miles).
When it wouldn't go into 3rd, it felt solidly blocked, not just stiff. When it is working, there is no stiffness or anything else to suggest a problem.

 

[BikeDoc]

I suppose that's possible, did you look through that guide?
The cover has a small raised 'nub' on the inside, I'm assuming to stop the selector going too far, it's c**p getting between the nub and selector that causes the problem.
I guess it could happen with other gears, but without seeing inside the box it's only a guess.
It may be worth draining the box, and refilling with fresh oil.
Drive it for a good few miles to get the oil nice and hot before you drain it, hopefully any c**p will get flushed out with the oil.

Be careful when draining it obviously.

I'd drain it by removing the cover personally, you can keep your hands away from the hot oil then.
Remove the middle bolt at the top, wind it back in a couple of turns, then remove all the bolts except that one, starting at the bottom.
If the cover doesn't come loose by itself, give it a sideways tap with a rubber/plastic mallet, or use a piece of wood/plastic as a drift.

 

[chr1s]

Thanks for the reply. I haven't had the problem since, so I will wait and see if it re-occurs before doing anything (cold weather and working at the side of the road are not very appealing).
But would the selector be moving in the opposite direction for 3rd gear, making it more difficult to get at any build up of swarf ?
(It did feel to be solidly blocked - not as if it was stiff and good shove might compress the blockage or get it past the blockage.)

 

[BikeDoc]

Guessing again here, but it could be something solid floating around, such as a bit of broken geartooth.
If it's not something like that, I'm not sure what it could be, being unfamiliar with the internals
Might be worth draining/refilling anyway, you might be able to get a magnetic drain plug for it as well, might 'catch' anything that's circulating with the oil.