What gear oil to use in T50 and Diff?

[yabaiani]

I’m curious as to what people use for oil (brand and weight) in a non-grinding T50 as well as the diff.

I was thinking of doing either AMS Oil 75W-90 in the transmission or Redline Shockproof 75W-90 GL-4.

Any other thoughts?

[totta crolla]

Redline transformed the gear change in my T50 gearbox and l like Motul 90 PA for a TRD diff.

[jondee86]

I used, liked, and recommend...
AMSOIL 5W 30 manual synchromesh transmission fluid for the gearbox, and
AMSOIL 75W-90 severe gear oil for the diff.

Cheers... jondee86

[totta crolla]

Just wondered if there is an issue with mixing synthetic with mineral oils (however small the quantity) for these applications?

[sirdeuce]

They sell blends.

If you are thinking it's and issue changing from petroleum based to synthetic and are concerned about the little bit that doesn't drain? not an issue.
Either way you go you might look into HP and friction reducing additives. I've used both the Sulfur and phosphate based additives and like them both. Sulfur based additives can cause a bit of chemical erosion with condensation and heat creating a tad bit an acidic psesence in the oil.

Ford does have a great gear oil available, has a friction reducer that actually reduces the power loss through the power train.

[jondee86]

Just wondered if there is an issue with mixing synthetic with mineral oils (however
small the quantity) for these applications?

Good question as usual Given that manual transmission oils and differential oils are quite
different and have different additive packages, I wouldn't mix those. But I don't see any problem
in mixing two different manual transmission oils or two different differential oils. The amount
left in the transmission or diff after draining doesn't amount to much.

I would not recommend mixing larger quantities, like 2 litres of decent synthetic with 3 litres
of cheap mineral to fill a gearbox. Use the correct amount of whatever grade/type the vehicle
manufacturer recommends... that will give the best result. As suggested above, there are also
specialist performance enhancing oil additives available for race and high load situations.

Cheers... jondee86

[davew7]

I have had very good results with Red Line MT 85 in the trans, do not use any GL-5 rated oil in the trans, because of the syncho's made from a brass alloy. For the diff, I use Valvoline 75W-140 with 4oz of Ludrilon gear treatment. I would not use any type of additive in the trans, only GL-4.

[yabaiani]

would AMS Oil 75W-90 in the transmission be good or no? or should i go with either Red Line MT 85 or AMSOIL 5W 30 manual synchromesh transmission fluid?

what are the pros and cons of either?

[totta crolla]

would AMS Oil 75W-90 in the transmission be good or no? or should i go with either Red Line MT 85 or AMSOIL 5W 30 manual synchromesh transmission fluid?

what are the pros and cons of either?

Did we just go around in a great big loop, wasn't this the original question?

[yabaiani]

would AMS Oil 75W-90 in the transmission be good or no? or should i go with either Red Line MT 85 or AMSOIL 5W 30 manual synchromesh transmission fluid?

what are the pros and cons of either?

Did we just go around in a great big loop, wasn't this the original question?

we did...lol. sorry, i meant more on the Red Line MT 85 vs AMSOIL 5W 30 Manual Synchromesh tranny fluid. I just dont know what the pros and cons are of these.