6 speed box - oil problem

[sjmmarsh]

I want to check the oil level on my 6 speed box as it started to baulk on gears 1-4 last time I took it out after about 30mins, presumably after the oil had warmed up.

 

I have made a 10mm key from a sawn-off allen key and a 10mm ring spanner, but the plug seems to be seized tight as it won't budge at all, despite moderate persuasion with a small hammer and leverage with my arms that was sufficient to rock the car on its stands (so I stopped). There is some sign of oil leakage from the speedo drive, but it doesn't look anything maor.

 

Presumably the plug was overtightened last time it was in the garage, but as it is not load bearing I am surprised that it is this tight. Is there any knack to loosening the plug?

 

The car is an SV, so the plug is behind one of the chassis bars, so approaching it through the side of the transmission tunnel is not an option.

 

Any help would be appreciated!

 

Steve

[sjmmarsh]

I have just trawled the wisdom of BC and found that taking the top of the gearbox is an alternative route.

 

Access to the top is OK. Removed six 10mm bolts without a problem. However the top will not release its hold on the gearbox - it seems that the top is held on with some white 'goo' as there was some on the threads of the bolts I removed.

 

I am reluctant to use force on this as I don't want to damage the gasket - any tips on how to do this?

 

Steve

[Bozz]

Steve

 

IIRC there is no gasket on the top cover.

 

A tap with a soft faced hammer broke the seal when I removed mine.

 

Bozz

 

McLaren Orange and Black 1.6SS 6 Speed here

[CharlesElliott]

There is a gasket on the 5 speed, don't know about the six.

 

You sure that six bolts are all of them?

 

If so, I agree that a sharp tap with a soft faced hammer should have it off. (The 'goo' stuff is the equivalent of threadlock - it's not holding the cover on)

 

Charles

---

My SuperGraduates 2006 diary

My SuperGraduates 2005 diary, My Caterham Academy 2004 build and race diary

[Stuart Faulds]

Steve, the top of a 6 speed is sealed with silicone (or similar), but it's a right bitch to remove. A chisel into the front left corner is my preferred method since there's enough gasket face there to permit a bit of abuse.

 

FWIW, the fill plug seizing is not unheard of on these boxes - I never use them for that reason (well, partly anyway).

[DohNut]

I am sure there are more than 8 bolts

[SouthernBanana]

Using a hole saw, I (Gary May) cut a neat 25mm hole in the side skin in the driver's footwell beside the gearbox which gives very easy access to the fill plug. The hole is easily 'filled' with a rubber grommet.

[Dazzled]

I've just checked the photos of my build and I can confirm that there are 6 bolts on the top casing of the 6 speed box.

 

I'm interested to hear if the tapping with a hammer method works as i'm planning to top my gearbox oil up by the same means.

[Casbar]

Older 6 speed boxes have a rubber seal set into the lid which seals the top. But once the lid has been off, the best idea is to bin the seal and seal the lid with something like wurf RTV Silicon

[TonyR]

I always remove the lid to check the gearbox level. Its so much easier, quicker and cleaner than trying to remove the side plug.

 

Tony

[Mr Locust]

SB,

 

if it is anything like mine a tunnel hole doesn't help. Caterham had a bespoke gearbox produced with the fill plug right next to a chassis tube in the tunnel!

 

Ian

 

Green and Silver Roadsport 😬

[Bricol]

Sawn off allen key - ie cut the short end down a little bit more. Insert sawn-off bit into plug, slide suitable length of metal tube over long end and push/pull depending if you are working from up top/underneath. Metal tube can be as long as required to get leverage.

 

Then a nice length of ali tube carefully formed into a 90 deg bend, connected to oil bottle cut down as a funnel works pretty well to fill it up - works for the diff too, out through a rear wheel arch.

 

Tip with the oil - stand the bottle in container of hot water to warm the oil and make it flow - someone I used to know who had to get litres off the stuff down the 2ft long gearbox dipstick tube on an integrale (only way to do it) used to microwave it - ever heard a microwave bog down under load? Although I'm not too keen on that idea as I don't really know what the microwave energy does to the oil molecules.

 

Bri

[patneale]

Are you absolutely sure that you are not tightening it up! When you are under the vehicle and at a funny angle, it is easy to get confused. If I remember correctly you have to push the Allen key towards the back of the car to undo underneath. I have SV ,but have never checked the oil since new in 2003 and 26,000 miles. The casing is absolutely clean and there is no sign of a leak anywhere and that goes for all the liquids. Never had to top up any at all. All mechicals have been totally OK on both my cars Total over 40000 miles. BUT the Gauges........ On 4th oil pressure sender and this new one is the worst....... Start up 7 rising to 8 in the gears and never below 7 at 70 MPH..... Should be 4 ish when hot... ( But only one trip and now laid up for winter)

In theory if there is no leak and I mean drips not just a mark around the gaskets and the tail shaft bearing the oil level will not drop. gearboxs don't burn oil.

Could you have used a less than good oil ? The 6 speed needs absolutely the correct oil.

If you do get the plug out I recommend Slick 50 is added,which is in mine and it is as named SLICK.

Years ago I lost 3rd gear on a TR 7 convertible for about 6 months. It just would not go in. As a last resort before ordering a replacement box I put in Slick 50 and quite remarkably driving out of the garage it went into 3rd just at the first attempt and was back to normal by the time I returned home. It just might work..... Last month I was trying to remove the bathroom radiator for redecoration and could not undo the nut and had to call the plumber.... Because of the position and angle I was trying to do it up....... What a fool ! and I have removed numerous radiators in the past. So check again you are not doing it up... The casing is alloy so it must NOT be forced!

[sjmmarsh]

Patneale

 

I am pushing the allen key towards the front of the car (hanging down below the car), turning the plug anti-clockwise, which is the normal way to undo nuts. I do know what you mean about getting the directions mixed up though as it is easy to get disorientated.

 

I also made a cut down allen key with a 'breaker' bar attached. I thought that it was working at one point, but it turned out to be the corners coming off the allen key. I suspect the plug is a bit rounded now as well...

 

I also had no joy trying to pry the lid off the gearbox - it has definitely been stuck on with silicon and won't give its grip up. Molegrips on the lid won't budge it and I suspect the attempts to lever it up are just digging into the aluminium rather than breaking the seal, so I have stopped to rethink.

 

Steve

[patneale]

Steve,

I assume that your filler plug is on the passenger side of the car like my SV 6 speed. If so if you are pushing the allen key towards the front of the car from underneath you are turning it clockwise, which is tightening it !

I made the same mistake with the nut on the bathroom radiator as I was looking at it the wrong way round.

A good way to think this out is to imagine that your eye is on the end of a screwdriver or key.

So approaching the plug from the passenger side of the car anticlockwise with the allen key would need the key to be turned towards the back of the car from underneath or front of the car from above i.e.under the bonnet.

Hope this solves the problem.

You may find that as you are now hopefully going the other way that there is enough "bit" to undo it. If you have enough left on the allen key for it to "bottom out " at the end when inserted, you could take about 1mm off the end of the key to bring a less rounded bit of key into play.

Sadly it sounds like a box out job to remove the plug so you can "attack" it at a more favourable angle.

[patneale]

Steve,

Further to my recent reply

If you , say, use an allen key to remove the wheel nuts, with the key hanging down, you would have to push the bar forwards to undo the nuts on the drivers side and and backwards on the passenger side...... If you went under the car from the drivers side then forwards on the key would seem to be correct on the gearbox plug whereas the "key" is entering from the passenger side and needs to go the other way.

[Grim Reaper]

The fill hole on the Caterham 6 speed box is on the drivers side, at least it is on mine!

[Ged]

And mine, there is a drain hole on the passenger side.

[patneale]

My car is 87 miles away in Brighton for the winter so cannot check which side the oil filler is located.. But very sure mine filled from the passenger side. Just looked at the manual and there is a picture from the drivers side ( Section 2 Annexe A page 20 fig 20) and there is indeed a plug on the drivers side. However this is mounted very low... below the bottom of the tail shaft bearing and as the manual tells you to put in 2 litres of oil I doubt if there would be room to get it all in. so think it is the drain plug. ( Manual does not say which side the filler is or show diagram) However the higher of the two will be the filler which ever side. The plug appears to be a black metal one and there should be enough sticking out to get a set of mole grips on it if the allen key has burred. You can gain extra room if you release the two nuts on the bolts sticking through the black plate under the rear of the gearbox and lever it over hard against the chassis the other side. You must make sure that you put it back again in the correct position as the gearbox will bang against the chassis under heavy loads , there will probably be obvious marks where it was originally fitted.

[Mr Locust]

Pat,

 

the picture you mention definitely shows the fill plug under the 'RH' of the CateRHam script, on the right side of the box as installed. It is a fill to level plug and from memory takes around 1.75l of oil. The drain is at the bottom of the casing on the left side as installed (on my gearbox at least).

 

Steve,

 

I have just re-read your original post and that is (apparently) a classic symptom of the wrong oil. The box requires a GL4 grade oil (IIRC) and GL5 can make the synchromesh operate poorly as it is 'too slippery'. Symptoms of the wrong oil are gears being difficult to engage and/or disengage. From a discussion with a helpful member of the Caterham technical staff whilst building my car Redline MTL was recommended. Search blatchat for extensive discussions on this subject.

 

That is, of course, looking at the obvious things first and assuming that there isn't a fault in the gearbox which would require a strip and rebuild. Fingers crossed!?!

 

Ian

 

Green and Silver Roadsport 😬

 

Edited by - Mr Locust on 30 Dec 2006 13:39:22

[sjmmarsh]

Ian

 

The oil should be fine as it is the oil that Caterham put in it when they serviced the car before I bought it 14k miles ago. In my case I think it is not enough oil rather than the wrong oil. The small leak I have had from the speedo drive has obviously added up over the last year or two.

 

It is just a shame that it didn't warn me about this before it went in for some work at CML, rather than just afterwards.....

 

There is also a 1/4 inch grub screw in the front LH side of the box at the top (just under where I have been trying to pry the lid off). Is this an alternate way of getting oil into the box? I realise that there is a danger of overfilling if I do this, but it may be possible to put a bit in to see if it cures the problem temporarily.

 

The next thing I will try (once it stops raining!) if to drive the car and get the box warm, to see if this expands the metal enough to loosen its grip on the plug enough...

 

Thanks for everyone's help to date.

 

Steve

[Casbar]

I've had a small leak from the speedo drive for some 2 years now, and when I took the lid off the box, hardly any oil was missing, as filling upto the plug hole, is loads more than is needed.

 

Did Caterham actually check the oil on the service

 

If the lid is stuck on with silicone, as mine was, can't you just pursuade it apart with a sharp flat object, as the faces are both flat.

 

Good luck anyway, I always take the lid off and not bother with the filler plug

[sjmmarsh]

Casbar

 

I presume that Caterham checked the oil level when it did the 24k service (at 23k) but that was 8k and 18 months ago. As the car is over 5 years old now, I have decided to do my own servicing in the main, but this is my first attempt to do a main service which includes the gearbox oil check.

 

The main reasons for doing my own servicing are a) to learn more about the car and b) because it is a pain to get the car to and from CML, even though it is only 40miles away. I tend to use CML for the 'hard' stuff like engine work and flat flooring. Having said that, my recent experience makes me appreciate the work that must go into (some) servicing!

 

I have tried persuading the top off with a rubber mallet and a piece of dowel resting on the corner edge of the top. The dowel split on the top of the box (so I was using some force) but it didn't move. I have also tried to pry it off with a chisel (the tip broke - so I need to watch out for bits when I eventually get it off) and pry it off with a garden tool used for cleaning cracks in paths (a bit like a strong pallet knife with a chamfered edge). Nothing seems to work - perhaps because I am concerned about any damage I may cause, so haven't hit it really hard. Using steel tools on an aluminium box worries me.

 

I will check the clutch settings when It stops raining as CML replaced the clutch cable when I took it in earlier this month, but I think this is just a coincidence.

 

Steve

[Mr Locust]

Steve,

 

I have never stripped one of these units but would discourage undoing anything other than the fill/drain plugs unless you are sure what it is. Generally a recipe for loosening shafts or having detent springs and balls come flying out (which is bad). If you are concerned about the oil level, I would concentrate on the fill plug. My 'special' hex key was shortened as described in the manual AND slimmed down to approx 1/2 its normal thickness on the outside of the bend to get it in. You can also squeeze a little extra space by loosening the gearbox mount to chassis bolts and prying the tail of the box over in the chassis. Really good stands required if you don't have access to a pit or a 4 post lift. It WILL move with a 2' tube over the key!

 

Is the clutch bite point any different than before the cable was done? Seems a coincidence if this started when the cable was changed.

 

Ian

 

Green and Silver Roadsport 😬

[mav]

Easiest way to get the oil into the gearbox, once you have got theplug out, is to use an easibleed