Transmission Fluid

[Jon W]

What automatic transmission fluid do you guys use when you change the transmission fluid? Thanks

[Stu Jackson]

The latest edition of Dexron.

[Jim Hardesty]

Same as Stu.

[sailaway]

the most important is changing it. I let mine go for a couple years it changed color to gray. That is not good I used a small pump on my drill motor to suck it out. Had to do it more than once to get it clear. If you can go in reverse not forward your clutch  pads are gone . Charlie

[Bill Shreeves]

I experienced the extreme result of my PO never changing the gearbox fluid.  Boat was re-powered along with a new gearbox 11 years before I bought.   I thought I was golden.  Learned, after purchase and careful inspection, that the gearbox dip stick was never pulled because the mfg paint wasn't cracked.  Drained a small amount of dark, thick burnt cherry fluid from it and saw the reason for it slipping when shifting to FWD.  Couldn't trust it, installed a new gearbox.  IMO, change your fluid every season and or every 100 hours with the latest Dexron, whichever comes first.   Penny's to save thousands.

[KWKloeber]

What automatic transmission fluid do you guys use when you change the transmission fluid? Thanks

The answer is, always use your engine Ops Manual as your first choice for information about most anything. 

The original manual calls for Dextron II, and the newest manual calls for Dextron II or Dextron III.
Dextron VI states that it's backward compatible with Dextron III.

Note that Hurth used Dextron to test the trans, then drained it. 
But then the Ops Manual ambiguously states that either GM (i.e., Dextron ATF) or Ford (i.e., Type F) fluid can be used.  However, the two types should NOT be switched OR mixed if adding fluid. 

One would presume that when commissioned, Dextron (GM) AFT was used, BUT like everything "marine" there's no 100% guarantee, nor any guarantee what a PO may have done (e.g., grabbed a bottle of Ford type F off the shelf at the auto parts store, or worse used the wrong type Ford Mercon fluid.)

Because I was unsure what was in there, I flushed, flushed, flushed, the old out before refilling, and then I knew exactly what I had in there for the future and beyond.

k

[Ron Hill]

Jon : It's said above - Just change the transmission fluid (Dextron oil) every season.
Just like you would with the engine oil - even if you didn't have 100 hrs last season. 

A thought

[DaveBMusik]

Just a quick caution to others, If your boat was repowered, make sure to check the label. I have a Yanmar with a Kansaki transmission which uses straight 30 weight oil.