[NickD]

First and foremost, is a dexos approved engine oil, but many manuals in the past also used conventional motor oils, this is full synthetic.

Its the only oil I can find that claims to be equivalent to GM part number 19259104, but in years past, with a number of different transmission oils, Royal Purple makes a Synchromax oil exclusively for manual transmission vehicles and cross referenced to GM part numbers as well as many other vehicles.

But they do say, Synchromax was intended for manual transmissions that originally specified automatic transmission fluids, yeah they used these too. In my Hondas, was just using conventional motor oil, never had problems with these. Unlike engine motor oils, a manual doesn't have all that acid and carbon crap in it so should last a lot longer.

The claim for Royal Purple has some kind of fillers in it to fill those microscopic size holes in wearing parts for reduced friction and much cooler operation.

Dealer price for part number 19259101 is like 40 bucks a quart, HPS is more like 9 bucks a quart, but can buy XRP for around 17 bucks a quart.

Can't find any specification on exactly what 19259101 is, for all I know, is the cheapest synthetic oil you can buy or maybe even a blend. Some here say 19259104 is crap.

Ha, sure would hate to lay out 120 bucks for crap and I can read something is great for only 27 bucks.

Opinions and experiences would be welcomed on this subject. Royal Purple is the only one that says its equivalent to that gm 19259104. Reviews I have read say its much better than that OE stuff.

 

[Tomko]

I used to think that Royal Purple supplied a superior product.

Now I realize that they have a cool marketing spin with that purple colour and simply bottle whatever they can buy from the spot market.

Seems to me that Amsoil has a product that people have had success with.

 

[XtremeRevolution]

One guy tried it. Don't know what his results were. It will never find its way into my transmission. Also, HPS isn't dexos1 approved. Too much ZDDP for that to happen.

My analysis, based on independent oil analysis, is that the EP additives are too aggressive and in far greater quantities than the OE fluid, and will result in accelerated synchro wear with this oil. I also have serious doubts about an engine oil having the proper friction modifiers for smooth synchro engagement.

Reviews are not written by lubrication specialists. Keep that in mind.

 

[NickD]

Fleet Farm is starting to sell some Amsoil products, ha, good take a drive up to Superior and see what they have.

Realize you can't believe what you read, not even about 5% of it.

 

[XtremeRevolution]

Fleet Farm is starting to sell some Amsoil products, ha, good take a drive up to Superior and see what they have.

Realize you can't believe what you read, not even about 5% of it.

Depends on who's writing it...

 

[money_man]

Put in the amsoil, everyone on here who has used it has loved it.

 

[NickD]

Depends on who's writing it...

Do I believe this from the Amsoil site?

"Manual Transmission,M32 (6-SPD)......GLS [2]
All TEMPS......
No AMSOIL Product Recommendation"

[2] includes GM P/N 19259104

True, while the GM dexos list only shows Royal Purple "SAE" oils, Their "XRP and HPS" oils claim to be far superior to GM dexos specs with added anti-friction materials that one would thing would extend the life of sychros.

Ha, in my early 30's vehicles, MT had zero synchros, so never had to be concerned about them wearing out Had to double clutch, step on clutch to neutral, step on clutch again to bring the gears up to speed while guessing at the engine speed, then shift into the next highest gear. If not, would grind gears like crazy.

37 Caddy and 41 Buick had sychros, but only for 2nd and 3rd gear, to shift into first, had to be a dead stop or would grind like crazy. Were easy to replace and only around a half a buck each as I recall. Not seeing any replacement syncros for the Cruze, only show the entire transmission as a replacement. So syncro wear is a concern, but I guess if they do fail, could always double clutch.

Did look at my oil, a 5/16's hex or allen bit fit the best, used a long screwdriver for a dipstick, still looks like new, even taste like engine oil. So what is GM supplying for 40 bucks a quart?