AX-15 Fluid

Ecomike said:

SDS sheets show no hazardous ingredients in MT-90 (if you believe that) the Penzoil Synchromesh has a zinc...-di-thio... (Thio meaning sulfur) compound in it, so I would not trust it. It was Penzoil GL-4 (or 3?) that ate mine in 2006!!!

Click to expand...

I though the ZDDP was preferable to using the sulfur-phosphorus based EP additive in GL-5? The main issue with GL5 is that it uses about twice the EP additive and uses sulfur-phosphorus compounds which increases the wear on the synchros and actually becomes corrosive to brass if it you overheat it. Plus, the extra EP additives reduce the friction at the synchros too much so that you get poor shifting and the extra slippage adds to the wear on the synchros.

Green XJ Jeep said:

I personally have not had and issue with it and I have over 320k on my AX15.
If I can find MT90 when I do my change before summer I will use it because the after I hit the 300k mark the trans seems to be running a little warmer than normal.

Click to expand...

Penzoils says it's safe for yellow metals, and specifically warns that GL5 is not safe.
http://www.stealth316.com/misc/pennzoil_gearoilsummary.pdf

Ah, ha, that makes sense, I had no idea it was too slippery and that made it wear the brass, very interesting, but I can see that.

The Penzoil SDS showed 5% (IIRC) and it was a Zinc ...thio-phosphonate (thus a sulfur phosphorus).

The new engine oils have gone from ZDDP to IIRC ZDPP? or some modified molecule similar to ZDDP but has less phosphorus.

I thought the zinc was the problem with killing the cat converters that EPA had issues with, but later learned a lot of the problem is the phosphorous (diesel oil has too much of that and kills Cats to...) (or maybe both?)

But now you have me wondering what the GL-5 EP additive is?

lawsoncl said:

I though the ZDDP was preferable to using the sulfur-phosphorus based EP additive in GL-5? The main issue with GL5 is that it uses about twice the EP additive and uses sulfur-phosphorus compounds which increases the wear on the synchros and actually becomes corrosive to brass if it you overheat it. Plus, the extra EP additives reduce the friction at the synchros too much so that you get poor shifting and the extra slippage adds to the wear on the synchros.

Click to expand...