ZF63A gear fluid change, stay with ATF or switch to 15-40 oil ?

[Bill Desmarais]

Hello All,

I’m about to do a fluid/filter change on the ZF63A gear coupled to the 6BTA 370 in my lobster boat.

There’s been lots of discussion on other forums on whether to run ATF in the 63A gear as listed by ZF……..or…..switch to 15-40 oil

that is also approved by ZF in the 63A gear.

The change from ATF to 15w-40w oil supposedly “quiets” the gear rattle and shift banging.

Anyone have any thoughts or opinions on this topic?

Anyone here on the forum made the switch to oil with their gear?

Thanks,

Bill D

Topic

[Tony Athens]

Just within the last 6 months, “100% hands-on” direct experience with a ZF85IV that runs on the edge as to “duty cycle” and power input in commercial service (1500+ hrs per year) has shown superior shifting qualities and measurably lower oil temps (a solid 20 F drop) …………… We just installed his 3rd gear at 6000 hours and we hope to get an extra 1500+ out of this one running 15W-40…… Gear #1 & #2 lasted about about 3000 hours each.. I’ll let you know in about 18 months but the immediate temp drop and higher oil pressure after running for 4+ hours at high HP levels is telling the story to me………….. ATF could never hold OP after a few hours running at high loads and the oils temp that has always been monitored, is now quite a bit lower ( 140F vs 160-170F) ………..Sure it would have been nice to install a larger ZF280IV, but the “fit would not allow it..

Tony

[Bill Fuller]

Bill

I have Hurth 630Atransmissions in my boat. Same trans as the ZF63A.
My manual says very specifically:
“Fill with 4.23 US-quarts (4 liters) of Automatic Transmission Fluid (ATF)…..”
And then in big letter and highlighted :
CAUTION
“Only use automatic transmission fluid as specified in chapter VII, technical data.”

Rob,
These are called “Hydraulic” transmissions for a reason. And they do apply power to the gears via a set pf clutches, much like an automotive automatic transmission.

I know Tony is going to come in tell us that there are lots of wet clutch systems out there, such as motorcycle transmissions and many others.

I would stay with ATF. It has served me well for 5,400+ hours.

Bill

[leonaj99]

ATF has anti foaming qualities which may be necessary. In a BW velvet drive if the engine rpm is less than 2600 it is OK to use motor oil in lieu of ATF. Don’t know what the requirement is in a ZF gear.
I can say from my bearing engineering experience that motor oil is a better lubricant than ATF.

[Rob Schepis]

Wonder why they went with ATF at all, after all it’s not an “automatic transmission”………..

[Author]

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