M5OD shifts better when cold?

[BlackBII]

Hey y'all. Have a M5OD with ATF Mercon V, and it shifts TONS better when cold in the mornings. Maybe because the ATF has thickened a little?

Any better results you guys have had with a thicker oil?

 

[bcost882]

Unless it is because the components are cold. My clutch grabs harder on colder mornings but i dont notice a real diffrence in the shift.

 

[LittleHorse]

I've never had one shift better in cold, it's usually always been worse. I always figured it was the excess viscosity of the oil causing the gears to rotate with the tailshaft instead of rotating with the synchros as they should as I shift into a gear.

That's usually on vehicles that use gear oil rather than ATF though. I haven't noticed any difference in my M5OD. ATF is a lot thinner than gear oil obviously, so the effects would be different.

 

[BlackBII]

The slave is new, so that shouldn't be part of the equation. Anything else you guys can think of?

 

[LittleHorse]

other than the ATF thickening a little, that's all I can think of.

I suppose it's possible that with the case being aluminum and the internal contents being steel, that the thermal expansion and contraction is different between the two, causing some slight changes in clearance through the temperature range.

But it's probably the thicker ATF.

 

[Davis]

That's odd. My t-5 shifts HORRIBLY in the cold, and it uses synthetic ATF. Part of it is the shifter boot going hard from the cold, but the tranny itself does not want to shift.

Also, I noticed that Mobil 1 synthetic shifts much better than this Valvoline garbage I have in there now.