Recommended Gearbox oil for 6 speed.

[Andy Mac]

I have a 6 speed box on a 420R.

Nothing wrong with it, but they are noisy. So I will swap out the oil to see if an alternative works better to reduce the whine on overrun.

I am sure this has been done to death, but recommendations please.

[Jonathan Kay]

Which gearbox is this?

Jonathan

For the Caterham six speed box the best two threads I can find are:

"Which 6 speed gearbox oil?" (2001)
"Caterham 6 speed gearbox oil" (2018)

[Grant_7]

Out of interest, is your overrun at its worst in 6th?

[ScottR400D]

I used Comma first then changed to Redlne MTL which I feel gives slightly smoother changes. 

Can't say I've noticed any difference in overrun noise and I agree, 6th is worst. Nothing noticeable in 5th , 4th better than 6th but still some noise. Not really thought about the lower gears. 
 

 

[John Vine]

I use Comma SX 75w-90 GL-4 Semi Synthetic.

JV

[Jonathan Kay]

Is this for the Caterham six speed box or the SADEV sequential box used on the 420R?

Thanks

Jonathan

[Geoff Brown]

Three Sevens - two 5 speed & one 6 speed all filled with Halfords 80w/90 GL4 mineral. Never a problem with noise or gear selection.