Originally Posted By: dnewton3
This has been covered many times before. I don't know that you're going to find any conclusive data. You can do your research, but ultimately, you're going off the HD reservation, and will likely get flamed by some and praised by others.
Perhaps, but All I have ever seen is people saying "Yea, it shifts so much better" or "HD recommends it so why not use their fluids". On another forum I voiced my opinion on ATF use in a primary, and the thread was closed because I could not offer "proof" that ATF was better or worse than SYN3 or "Primary Fluid". I was just trying to figure if anyone knew exactly what primary fluid IS, whats it made of (Haven't been able to find a conclusive answer), and why it would be OK to use a motor oil in a primary, but not ATF, when in fact they are really similar sans weight differences, as in they both are mineral based oils. Some of the responses i get are:
ATF shifts better ( which, btw, I do agree with)
ATF is not OEM recommended so it wont work or live
ATF doesn't 'climb' on the chain (does 20w-50 non-ester oil climb?)and therefore doesn't lube but only half.
ATF isn't safe for the stator
ATF lives in trannies that have electronic solenoids so it Is safe for stators
Formula + isn't the golden fluid anymore now it's SYN3 (or equivalent)
Formula + is the only fluid that should go in a primary
Formula + has additives that only a primary requires
Motor Oil is safe for the stator
Motor oil is what the manual calls for only.
Motor Oil doesn't climb on he chain to lube, just like what you see on that lucas Oil stabiliser display (you know, the one with the plastic gears)
These are some of the arguments for the various fluids. I am just trying to figure out the differences in these fluids and why some should only be used, why others cannot be used, and why some used to be OK and now they are not, etc.
Motor oil lubes the chain better