Shift behaviour as manual trans warms up

[FTO-UK]

Took my Mitsubishi sports car out yesterday and paid particular attention to the shift behaviour. It currently has Redline MT90 in it (although I have some SF MTL-P on order).

I am still trying to educate myself about synchromesh operation etc. and wonder if anyone can explain the following:

When the transmission is cold it is very notchy and baulky shifting 1-2 and 2-3, but there is no grinding or crunching. Shifts 3-4 and 4-5 are not bad.
When the transmission warms up a little (after, say, 5-miles) then the shifting is a little better, but 2-3 tends to start crunching. This puzzles me - I would expect the warmer fluid to be thinner and therefore the 2-3 synchro to work better. What is going on here to make this happen?

 

[mechtech]

FTO - Good question. Manual trannys are tempermental in feel and lube requirements.
There is a good chance it will be a moot point, with the MTL P in it.
Give it a couple of hundred miles with the new sauce, and see where you are at.
Make sure your clutch is bled, and in adjustment, BTW.

 

[smith_t240]

my m46 in my 83 Volvo 244T is just the opposite. great when its cold, gets a lot thinner as it warms up. gonna try some amsoil supershift.

 

[MolaKule]

quote:

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gonna try some amsoil supershift.

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You might want to try our MTFGlide as well. GL4 protection with a slightly higher viscosity, and friction modification optimized for manual trannies.