Mobil1 20w50 Vtwin in a tuff torq K61

[gman2304]

I'm planning on changing the hydro oil in my JD LX188 and I'm considering using the mobil1 vtwin motorcycle oil instead of using the mobil1 15w50 which I used the last change about 10 years ago. The super syn is now api backwards compatible, sl, sm, sn, sj while the mc 20w50 is sj and I think has more zinc. Would their be any benefit in using the mc 20w50 over the super syn 15w50? The mc 20w50 is $9.70 per qt vs the 15w50 at $17.73 per qt.

 

[JTK]

I think any of those would be ideal for your TT being used in NC summer heat. Main thing is changing it at some interval.

 

[bchannell]

I used 15W50 M1 in my HydroGear on my previous Husqvarna tractor and it's still running today just fine for the fellow who bought it, so I would stick with whichever TT recommends. I don't think you gain anything by using motorcycle oil, but who knows. if I were determined to use 20w50 and that was on the list of recommended oils, I'd just use regular old M1.
I do know, but can't find the article right now, that HG (and possibly TT also) recommends using regular old dino oil in their trannies, but there was an official list published by HG that listed syn oils that the factory approved and M1 15w50 was definitely on that list.

 

[bmod305]

TT actually recommends 5w-50 syn not 15w-50, Most Napa's carry Mobil 1 5W-50. That is what I used in my K46 and my brother's K66. Both still going strong with 360 hours and 500+ respectively. Don't over think it.

Dave

 

[gman2304]

Originally Posted by bmod305
TT actually recommends 5w-50 syn not 15w-50, Most Napa's carry Mobil 1 5W-50. That is what I used in my K46 and my brother's K66. Both still going strong with 360 hours and 500+ respectively. Don't over think it.

Dave

Like I stated in my op I have had Mobil 1 15w50 in my 20 year old K61 for 10 years and it has done a stellar job. The 5w vs 15w vs 20w doesn't concern me because I live in a fairly mild climate and my mower is stored inside and not used in the coldest months. My concern is the current 15w50 not being as stout as the previous version due to formula changes in the last decade or so. A couple of lawn care forum threads concerning hydro oil have given positive opinions after using the Mobil 1 v twin 20w50 oil saying it seems to be more robust than the current 15w50 and it is api J rated.

 

[coder]

I have just read somewhere on this forum, that oils with a high viscosity index tend to shear down more in a high heat, high shear environment.
So therefore, a very high viscosity index is undesirable for hydros.

Maybe I misunderstood something, and this does not apply to synthetics. (I know that "thinning out" is a problem with friction modifiers that do shear down). So :
We know that the 2nd number is recommended to be 50. 60 is too high, and is said to run too hot. 40 may be OK, but borderline on the recommended minimum 120 celsius cSt. So: 50 is the 2nd number. The first number then should not be too low, unless there is a really good reason for it, such as operating the hydros in cold weather. (like, winter) . So 20W50 seems sane to me. Something like a 15W50 or a 5W50
would have a higher viscosity index, which may be undesirable, unless I misunderstand the "shearing down" concept as it relates to synthetic oils.

BTW. Gman2304 , when you say "robust" you mean "higher level of anti-wear additives", or "higher HTHS" or both, or something else?