zf transmission fluid?

[green allycan]

right so a few weeks ago i changed the filter in my auto then filled it with dextron III, it may be my imagination but i have a funny feeling that the trans is now running a bit warmer.

question is!
*is this the best fluid for the box?
*should i be running the full synth stuff?
* will the full synth fluid really bring the temp down, as is stated on the bottle?
*why have i found conflicting recommendations for auto fluids in books, on the net and reference guides, etc?

help on this issue would be very much appreciated, as i wish for my zf to last for ever!!!!!!

[green allycan]

come on guy's i am sure that some of you have thought about this,
what are your ideas on the fluids used in the ZF?

[amtravic1]

I usaully Dextron 3, usually valvoline because it is cheaper than other brands (you get 5 litres for the same price as 4 in other brands) but I once topped it up with a fully synthetic type and noticed a big improvement in the trasmission smoothness. I dont believe that just replacing the oil with the same type makes the transmission run hot unless the oil you put in is of very poor quality.

Ian

[rick130]

but i have a funny feeling that the trans is now running a bit warmer. (may be due to warm weather of late)

Not trying to be a smart arse, but if you don't have hard temperature readings to compare, I'd take a 'feeling' with a grain of salt.
How would it be running 'warmer' after a fluid change, unless you've used the wrong spec fluid in it.
For example, Dex II/III fluids have totally different frictional characteristics to Ford Type F fluids.

well, what spec fluid should it take ??

Dex IID, III, Mercon, Type F, ??

If it takes a Dex II/III type fluid, quite possibly one of the best available is Castrol's Transmax Z, a PAO/ester full synthetic.

A heavy vehicle operator I know, who has done a lot of testing for a number of the large oil companies can't speak highly enough of the stuff.
Lower peak operating temps and lower wear numbers/longer in service life than anything else he's used.

Most nearly all the mineral based Dex III fluids do an excellent job in service, but do oxidise and break down quicker when worked really hard/overheated. More frequent fluid changes prevent this.

[green allycan]

but i have a funny feeling that the trans is now running a bit warmer.

Not trying to be a smart arse, but if you don't have hard temperature readings to compare, I'd take a 'feeling' with a grain of salt.
How would it be running 'warmer' after a fluid change, unless you've used the wrong spec fluid in it.
For example, Dex II/III fluids have totally different frictional characteristics to Ford Type F fluids.

well, what spec fluid should it take ??

Dex IID, III, Mercon, Type F, ??

If it takes a Dex II/III type fluid, quite possibly one of the best available is Castrol's Transmax Z, a PAO/ester full synthetic.

A heavy vehicle operator I know, who has done a lot of testing for a number of the large oil companies can't speak highly enough of the stuff.
Lower peak operating temps and lower wear numbers/longer in service life than anything else he's used.

Most nearly all the mineral based Dex III fluids do an excellent job in service, but do oxidise and break down quicker when worked really hard/overheated. More frequent fluid changes prevent this.

first thanx Ian and rick,

Rick i see where you are coming from but i will try to explain,

the reason i said that was because the tunnel of my car felt quiet warmer then what i am use to, but you know what it like when you find somthing wrong with your car you become all ears and listen to any little wobble, shake and thump, but in this case feel of cabin temp while driving along is what brought the thought on....

In regards to spec fluid, i read in a booklet that rover spec the type F fluid that newer fords use. In another book i found Dextron III and another claim Dextron II. I also read that the tranzmax Z is ment to lower auto temp and is interchangable with dexIII, this would be a good thing.......

So i now change my original question.
Have many of you used the full synth (ie: tranzmax Z) in there ZF and if so were you happy with it?

[amtravic1]

If I was you I would use tranzmax z or another fully synthetic oil of the correct grade. My experience with engine oils is that using a fully synthetic oil lower the oil temp by 10 dreees c with no other changes. I will by using a fully synthetic oil in the transmission next time I service the transmission now I have replaced the leaking pump seal.
Ian