gomez123

I searched but came up empty on a definitive answer as to what ATF to use. Dextron 2 is no longer. Will Castrol Dextron/ Merc work? The bottle saay's not to use it in trannys that require dextron 6.

soontobered84

Gomez,

The manual says to use Dexron 3, but you can also use Dexron 6. I don't think that I would mix the 2, but if you're doing a complete change, I'd use the Dexron 6.

DeWolf

Valvoline Max Life. I've used it on all the auto 928's I've had and no issues at all. Nice smooth positive shifts.

dr bob

The Valvoline Max Life is a good full-synthetic alternative to "conventional" Dexron. The cars originally spec'd Dexron for the auto gearbox and the power steering system. Dexron has evolved with full reverse-compatibility, so any modern Dexron xx will work fine in our older Dexron II cars. I've used Castrol Dexron IV lately (last several changes), and also used Mobil-1 full synthetic early in my stewardship period. The Mobil-1 offered firmer shifts than what I'd become used to, so I went to the "conventional" Castrol at the next change, and everything settled back to 'normal' again. At that same time, a user in Phoenix reported some odd symptoms with the Mobil-1 that ultimately resulted in a new transmission from Porsche in his GTS. Many have used it without any issues, so it may or may not have been an odd coincidence. He didn't put Mobil-1 in his new trans.

My Honda Pilot DD gets a partial fluid swap with every oil change, in deference to Honda's history of trans failures in earlier cars. I use the full-synthetic Valvoline Max-Life in that car, and will likely use it in the 928 when the next gearbox service is due. Maybe because I buy it by the case and always have it on hand. It easily meets the Dexron standard so no worries.

Cleaned out the Max-Life references. Read further down in this thread...

gomez123

Thank you all so much.

GregBBRD

I've had two transmisdions, lately, which had the piston seals fail on both K1 and K2 very shortly after changing the oil to Valvoline Max.

It will be quite some time before I pour any of this stuff into a 928 transmission, again, but let me know how it works for you.

I've used "Shift Max" many times, if you feel you need a higher performance fluid/more expensive fluid....for some reason.

However, all my rebuilds and everything that is serviced here gets Pep Boys "Proline" Dextron III fluid. I've been using it for eons, with zero issues.

Spend "extra" money were it is really needed....there's plenty of places to do this on almost every 928!

The Forgotten On

I use the Pepbpoys brand as well. Works just as intended when serviced at the correct service intervals.

Pretty inexpensive as well. All dexron XX has to meet the same standards as any other dexron XX. so any of it should be fine from any local parts store.

They all use pretty much the same base stock anyway...

SwedeInSiam

I had bad experience with Valvoline Max Life in my 3-speed. Would not shift properly and it was expanding much more then normal when getting up in operating temperature. so much so if you had proper levels at warm then you could not see any oil when cold (cold is 32°C / 90°F in Thailand).
Then it could also have been a "copy", not always sure what you get in Thailand (even with women :-) )

I use a cheap Dexron III from PTT which is a local oil company and my 3-speed loves it.

GregBBRD

Made me smile and laugh.

A welcome thing, today!

dr bob

OK --

Pay no attention to what I said above about the Max-Life. Go with the actual experience of those who have used it and had poor results. I'll be shopping for another load of Castrol next time, since I know for sure that it works.

Thanks go to Greg and Anders for setting me straight.

I'll clean up my post.

DeWolf

I won't be cleaning up my post...lol. I really have had no issues with the stuff at all. Used it in 928's, 944, 996 and several BMW's. In fact the 996 was flaring badly between shifts and as soon as the oil and filter were change it was literally a different car to drive. Maybe Australia gets a different formulation?

GregBBRD

I'd be amazed if they shipped transmission fluid all the way from here to there....and I'm guessing that the import duties would make this stuff too expensive to use?

At any rate....two failed transmissions from the same exact (and incredibly rare) failure modes makes me want to not use this stuff, myself.

However, I'm completely cool if everyone else wants to use it.

skpyle

NAPA house brand Dexron III for the Red Witch. I've heard too many horror stories of perfectly good running Mercedes A28.** automatics going **** up after switching to newer synthetic ATF. Shifts becoming rough, clutches burning away, to outright loss of motion.
I also look at it this way: these transmissions are 1970's technology and design. They were designed with the thicker viscosity Dexron II in mind. Newer synthetic ATF is thinner viscosity and has different friction characteristics. In my mind, that is a bad match for our transmissions.
Caveat: I am referring to used, running transmissions. If you overhaul(not 'rebuild') one of these automatics with an eye for modern materials and such, running synthetic ATF might be just fine.

This is all my own personal opinions and beliefs. Your results may vary.

mkhargrove

I've drained my transmission and torque converter....and my head is spinning from the opinions in different threads related to automatic transmission fluid.
Should I stay away from the newest dexron low viscosity fluids?
It seems that the consensus here is to stick with dexron III types. But this thread is a couple years old, so I thought I would ask.....

The Forgotten On

Dex 3 or 4 is what you should use. It's safe, cheap, and it works perfectly in our cars. Go for a conventional of your favorite brand and you will be fine.

The same fluid is also used in the power steering system so you could give that a flush too if you feel the need for it.