Im planning on fitting my new transmission cooler sometime soon, should be a fairly straight forward job, although one thing Im hoping some one can help me with is topping up the transmission fluid, as the level will drop once the new cooler fills up. Anyway, Ive got no idea what type/brand is in there at the moment as I paid a mechanic to service my tranny a few months ago. Ive read some where before that its best not to mix different types of fluid, is this true? I would only be adding a very small amount as the capacity of the new cooler isn't all that large. Would there be any possible problems with topping up the fluid with a different type/brand? Any help would be great.

Cheers.

Has anyone else ever just topped up there auto tranny fluid with some generic fluid and not had any dramas?

SexedTF'n... i seen this on a car care site, tryin to find the link again..

Q - If you need to top up oil or fluid, is it important that you put in the same weight of oil/fluid that is in there, and if you can't remember what's in there, what happens if you mix different weights of oil/fluid?

A - If at all possible, when adding oil to bring oil/fluid level to spec, use the same weight oil/fluid that you have in the vehicle already. However, it will not hurt the vehicle to mix the oil/fluid weights. It is recommended that you service the vehicle as soon as possible if there is a large difference between the weights. Staying with the same name brand of oil/fluid is not as important as staying with the same weight - just about all oil/fluids manufactured now has the same "base".

Lubricants usually aren't too bad if you mix different brands as long as they are the same "base" and viscosity. It is only when mixing hydraulic fluids like brake and clutch that you may have huge problems with isomerisation (when 2 liquids mix they can sometimes form a new composite at the molecular level). This will cause changes in heat/viscosity properties and clogging of hydraulic lines, pumps etc... You're probably best off even ringing your mechanic and asking what fluid he would have used??

BTW that info you pasted IW, it contradicts itself twice throughout the paragraph???

Hows it going mate. still havent put my cooler in yet, I'm waiting till I am on my holidays in a couple of weeks but as you say it looks fairly easy. As for tranny fluids my mechanic just changed mine last month and had to get mitsubishi genuine fluid for it as his suppliers said that no other manufacturer made it. I dont know if that is just crap on his behalf or the suppliers but I suggest you look into it very carefully. I would hate to hear that the cooler went on fine but down the track the tranny crapped itself as the fluid was incorrect.

Thanks for the replys. Im going to give the mechanic who did the change a call tomorrow and ask what they would have used. Im considering doingn another flush and change myself using genuine mitsu fluid, just to be sure.

Cheers.

Spoke with my father-in-law how is a technical magager for castrol and he suggests you dont mix brands of oil. Reason being there are oils designed for electronic style transmissions like in your model. He said you should use a castrol product called TQM-ST or a TQ95 but toavoid dextron oils.
Keg.

Apparently what i've been told is that Magna's (well for 2nd gens at least) have to use the genuine mitsu trannie fluid. Although i have also heard that they are basically dextron stuff.

Apparently what i've been told is that Magna's (well for 2nd gens at least) have to use the genuine mitsu trannie fluid. Although i have also heard that they are basically dextron stuff.

Funny that, because my friend at Mitsu spare parts specifically advised against using genuine Mitsu fluid for the Gen2s as they have lowered viscosity to allow better performance on the Gen3s, but at the expense of Gen2s.

He suggested Castrol TQM-ST to be best in this case; I have used this fluid for around 40KKms now and can only give it praise. Look at it this way; I am still on my original gearbox at 255KKms and it still performs quite well but probably needs a rebuild in another 30KKms or so.