904 Transmission Fluid Recommendation
The testimony of the oil rep is too broad. Did his side win? Any fluid "might" work with most transmissions and not necessarily cause immediate or obvious failure, but it can't be good for it over the long term. It mainly depends on the formulation of the fluid and application of the trans. You said yourself that Type F feels different from Dextron, likely because there is less slippage in the same application. The newer the trans with more electronics, the more important that the correct fluid be used.
I agree that many trans failures after a fluid change are not the fluid's fault even if it's not the same/correct fluid. I've seen many people think that a change will eliminate slight slippage. But that actually means it's too late and the trans is already malfunctioning. New fluid can also act as a "cleaner" and loosen up any varnish, sludge, clutch material, etc. build-up inside, which can interfere with the trans functions.
I also realize that manufacturers try to sway people to use specific brands (like their own) making it sound like other brands may cause issues. But there are laws outlining that properly formulated fluids by other brands can be used without jeopordizing the warranty.
But bottom line is that there has to be a wider variety of transmission formulations for specific applications if one is to expect the proper performance. i.e.: Nobody will convince me that putting a Type F fluid in my 2004 Dodge dually diesel is ok!
Also, while synthetics may not be necessary in most applications, the harder a trans and converter is worked (race, towing, etc.), the better the synthetic fluid will hold up and help extend their lives over conventional fluids. Good insurance!
Yes, the side we testified for won. He was also a member of the SAE & was under oath representing his company so I greatly doubt he would be unprepared or misinformed about the subject.
The type F fluid is the one fluid without friction modifiers added, so therefore less slippage & reduced temps. We all agree that heat & slippage is the enemy of an auto trans. So anything that promotes less slippage & therefore less heat would be promotiung longer life of the clutches & bands etc also improving shift firmness. Thats why we use it in performance applications.
Transmissions today have way more gears & components inside them but the trans cases haven't gotten much bigger repectively. 10lbs of Sh*t in a 5lb bag! All those moving parts cause more heat. Add to that the fact that they extended the intervals of service (to lower the advertised cost of ownership). The factories need to imprrove the cooling ability of the fluid used & make it last for a longer period of time. Enter the synthetics & higher amounts of friction modifiers added. Using the older type fluids may require more frequent changes, more along the line of what used to be the norm, but they wont cause damage.
As for the use of electronics controlling the transmissions, the electronics are simply electric solenoid controlled valves rather than the hydraullic controlled valves we all have in our old 727s & 904s. You just now have the computer calculating & operating the valves rather than being limited to a governor & mechanical linkage doing it. The electronics have no idea what fluid is being pumped through the trans & could care less. All they know is the PCM tells it when to turn on or off.
I totally agree in racing the benefits of synthetics are certainly a plus. The original poster here said they weren't racing the car just limited use & road trips. On a racing transmission you would be doing a tear down at least once a season & doing a thorough inspection & repairs as needed. So even then non synthetics shouldn't be a problem. Synthetic does have it value in less varnish & lower friction & rotational mass when stuck to spinning components.
It still just comes down to simple hydraulics & mechanical fundamentals.
There is a lot of misinformation out there about what to use & scare tactics about the new fluids. Right here on FABO there was a thread where a guy had changed the fluid & filter in his trans & had a problem with the car afterward & there were a bunch of guys telling him it was because it was the type of fluid he used & he wasted tons of time & a lot of money chasing the problem based on their bad advice thinking it was the fluid when in fact it was a mechanical problem where the filter wasn't sealed correctly. Ended up as a very minor fix, but guys had him thinking he fried the trans w/ the "wrong" fluid. Too many guys speaking from what they believe rather than what they know, especially when they don't know or haven't bothered to find out.
I'm just trying to set people straight. If you want firm shifts go with type F or the performance brands. If you want to use a good ATF that is what it came with use the Dexron III (since you can't buy Dex-II anymore). If you want softer shifts that take away some of the advantage from the shift kit you installed & like to spend more money use the type 4 fluids. But whatever you choose it won't hurt it. Even in a big diesel. :banghead:
