CVT fluid contamination

Question

CVT fluid contamination

enginesrus (Mechanical)

(OP)

25 Aug 21 08:11

I am dealing with a CVT that has an attached transfer case for an all wheel drive system. The transfer case oil mostly all disappeared, approximately 3/4 of a paper cup of oil was drained from the transfer case. There are no signs of external leakage. The suspected loss areas are, a seal that would allow it to pass into the CVT and pollute the CVT fluid, or a shady service center. So the question is what is the best way to find out if there is 80W-90 gear oil mixed with the CVT fluid? I have searched and found nothing on this topic, so forgive me for turning this into trouble shooting forum. I suppose I will try to install the out put shaft and just fill it and see what happens, the unit is off the CVT. Next question would be how detrimental to the clutch materials would the polluted fluid be?

TugboatEng (Marine/Ocean) · Answer 1 · 2021-08-25 15:13:48

Oil sample. Gear oils typically have sulfur were transmission fluids do not.

gruntguru (Mechanical) · Answer 2 · 2021-08-26 02:29:01

RE: CVT fluid contamination

gruntguru (Mechanical) 26 Aug 21 02:29

Sniff test.

je suis charlie

3DDave (Aerospace) · Answer 3 · 2021-08-26 03:43:28

I would expect the lubricant to cause a friction clutch to no longer be a friction clutch. A buddy of mine claimed a friend added "Slick 50" to his automatic transmission and said the result was "unable to pull the hair from a caterpillar."

(Edit: it was hair. Not skinning caterpillars.)

TugboatEng (Marine/Ocean) · Answer 4 · 2021-08-26 06:28:48

The quality control on modern cars is so good nowadays if one car has a problem, they're all going to have it. If you could elaborate on the make and model that would allow us to tap the vast resource of user experience that is on the internet and would make it easier for us to help. If it's a Nissan, you're doomed.

romke (Automotive) · Answer 5 · 2021-08-26 07:08:49

whether contamination has taken place can be detected in various ways. a simple "sniff test" could suffice: heavy duty gear oil has a very characteristic smell due to the type of additives that are used. you could also look at the colour: most CVT oils contain a red dye, gear oil is brown or dark brown. a third way to decide whether contamination has taken place is viscosity - CVT oil is relatively thin (like ATF), 80W-90 gear oil is far thicker. a more sophisticated test would be to have a oil sample from the CVT checked by a laboratory and compare the figures obtained with a fresh sample of CVT oil.

if it is easy to obtain a oil sample out of the cvt and both colour and viscosity are more or less like the fresh cvt oil, the oil level seems ok and the cvt is still fully functional, i would not worry to much and just repair the transfer box.

the pourpoints of the two fluids are very different. putting some used CVT oil in a freezer at low temperature will show "clouds" within the fluid due to solidifying waxy components from the gear oil - the pure CVT fluid would not solidify at temperatures of say - 25 degrees C

enginesrus (Mechanical) · Answer 6 · 2021-08-26 21:28:55

I know the sniff test, the old sniffer isn't always up to snuff, sinus condition etc. 2004 Nissan Murano. My fill test showed leak external, output seal. There were no signs of that in the car or on the car, but then only about 3/4 of a dixy cup in it, since who knows when. These things are known for sealing problems. My main concern was or is the torque converter lockup clutch and gear oil pollution, just not sure where we are going on this yet. The flow control valve appears to be the low pressure problem so far with the transmission. Yes so many engineering errors in this transmission. The basic design is good.
I am actually impressed that the belt and variator pulleys are in the condition they are.

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CVT fluid contamination