Sticky six speed box

[Phil Bishop]

I've got a 1.6 K SS into a Caterham Six Speed box. Occasionally - not everytime - it sticks in one of the two 'forward' facing gears - third or most commonly fifth. I have been waiting for it to run in a bit, but I have nearly 5000 miles up now, and no sign of improvement.

 

It doesn't stick big time, but needs a bit of a tug to pull it out of gear, more than I was expecting, and enough to make an embarrassing mess of fast changes when approaching a bend or roundabout on the quick.

 

I think it tends to happen more after the box has not been in use for a few minutes, after a long straight stretch, and seems to get better when it has been 'stirred around' for a bit. It is also more of a problem after everything gets nice and hot on a run. I am running the Caterham recommended (own label) oil and it is all the way up to the filler hole. Apart from this, the box snicks between the gears nicely.

 

I am thinking of tilting the car on a kerb and seeing if I can persuade a bit more oil into the box. Anyone think it would help?

 

I.6 SS, 6 Speed box, BRG/yellow stripe and Brooklands!

[Paul Formston]

Hi Phil whats it like going into rev, if it sometimes crunches it could be a bit of clutch drag try adjusting it. If you over fill the gearbox you could have oil caming out of the seals so I wouldn't recomend that Phil, but try some fresh oil if the adjusting do's not work Regards Paul

[Mick Day]

Mine used to do this until I used Redline MTL oil.

[Colin Mill]

Certainly sounds like a lube issue. The type 9 box apparently hates GL5 grades - perhaps the 6 speeder is similarly picky about oil type.

[Nifty]

I don't have a 6 speed but Ernie commented to me the other day just how much better his gearchange was after refilling with the Caterham supplied gearbox oil, so I would go along with the above suggestions

 

Keep off the straight and narrow 😬

[Mr Locust]

What you need is a gear oil with an API classification of GL4. If you put GL5 in the synchromesh is not so effective - worth checking if you still have the bottle kicking about.

 

Redline MTL is works well as others have said.

 

Ian

 

Green and Silver Roadsport 😬

[Phil Bishop]

What I used was a 80W/90 GL4 as specified by Caterham. Couldn't get any more in - running down to my elbows in the end !

 

I had wondered about the clutch, as I get the occasional 'graunching' noise/feeling as I pull away and slip it a bit. But the bite point seems to be where it should be, and no other symptoms.

 

I would imagine it is lubrication thoiugh, as it never happens on any of the gear changes pushing 'up', that is, out of 2 or 4 - but only pulling down out of 5 (mostly) or 3 (occasionally). Also, only comes on when everything is hot - which makes me wonder whether the thinner hot oil is not getting to all the parts other oils might reach.

 

If I decide to change to Redline over the winter, would I need to flush out the old oil - or just let it drop a while and then refill?

 

I.6 SS, 6 Speed box, BRG/yellow stripe and Brooklands!

[Allen Payne]

I can't see the type of oil woudl cause an issue changing out of third, but not out of second. Give Phil Stewart at Road & Race Tramissions a call - he may know of another cause.

[Mr Locust]

If the oil is up to the fill hole I would try the clutch adjustment. If nothing else it eliminates it. Wind it up so the pedal sits 1" or so higher and see if it is any better. Could your 'graunching' reference be the cable seizing or breaking?

 

Ian

 

Green and Silver Roadsport 😬