Hi there,
Been searching the threads looking for advice on which ATF to put in my '91 Max. Page 9-3 of the owners manual has the following diagram in it, which refers to SAE viscosity numbers for various ambient temperature ranges :-



Can anyone decipher this for me ?. I live in Queensland Australia where the temperature never gets below 10 dec C and sometimes gets above 40. So do I need a 140 vis oil ?. The transmission was re-built about 90,000 kms ago and is showing sign of some lagginess shifting up from 1st to 2nd and 2nd to 4th. Would a higher viscosity oil be better suited to help cut down on slips?.
Perhaps a 80W-90 instead of the 140 ?.

 

That diagram is for 5-speed gear lube, not automatic transmission fluid. I don't know what's available down there, but Mobil 1 and Amsoil are popular choices here on the org. Good luck.

 

Oops !. There goes my tech creds. May be another dumb question, but if manual gear oil has a wide range of vis for different temp applications, shouldn't ATF have different vis's also ?.

 

Nope. ATF is used to push the car around, rather than lubricate, so it doesn't have different temperature ranges like gear oil.

 

What lubricates the clutch packs and friction bands ????.

 

Amsoil can handle the most severe of circumstances and Mobil is right there as well. There are none better.

 

Ok, technically it lubricates as well. But that is not its main function.