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Clunky Gearchange


Alexander Gurr

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Hi Guys,

 

I have a new build Academy car that I have now put about 250 miles on and one thing I really can't get used to is the gearchange. It is a standard 5 speed box and seems quite clunky compared with the 6 speed box in my old car. It is particularly so when cold, where the first to second shift is next to impossible. Has anyone experienced anything similar 🤔

 

My thoughts are that:

- the gearbox oil is wrong - I used Coma (I think it was 80/90)

- there may be insufficient gearbox oil in the car - I got an extra litre in (I think) when building and Caterham told me they checked the level, as requested, at the post build

- the clutch may not be engaging sufficiently - I don't know why, but it just doesn't feel quite right, but this may be because it is now hydraulic vs the old cable operated clutch in the old car

 

Has anyone else experienced similar issues in the past 🤔

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To check for clutch drag jack the back up on stands and with the engine running put it in 1st and keep the clutch down. Do the wheels turn? Probably not this if it's only when cold.

 

Check the oil level is up tot he bottom of the filler plug then consider a change of oil - can't recall what's recommended these days but think I swapped to Redline MTL when I had a similar problem on my 1st Seven with the 6sp. Change of oil helped considerably.

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Quoting Mark Durrant: 
The recommended gearbox oil is a 70W80 GL4. Do not use GL5.

I recall reading somewhere that the recommended gearbox oil was 75W90 GL4, but cannot find the source. *confused*

 

I use Redline MT-90 (same as MTL, except it is a 75W90 GL4 gear oil rather than a 70W80) in my BGH 5-speed, and it works great.

 

Edited by - BBL on 22 Jan 2012 03:43:01

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Just checked and it looks as though I have used 75W90 GL5. What is the difference between GL4 and GL5 🤔

 

I will give Caterham a call and see what they recommend, but if there is a problem then it looks as though I will have to drain the box and start again *mad* Funnily enough the car ran very well yesterday, with the gearbox feeling much sweeter *confused*

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GL4 will improve the shift over GL5, I've had a few boxes running GL5 spec oil Caterham and road cars where the shift speed has been much improved by a switch to GL4 of the same grade.

 

As previously stated GL4 allows the syncro rings to break through the oil film faster and so allows a faster smoother shift.

 

For my Caterham 5 speed I used Redline MTL and found it gave perfect perfomance.

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