Transmission Fluid or motor oil

[Easternshore]

We moved and I’m now doing most of the maintenance myself. Time to change the trans fluid and filters in my Hurth ZF 63A transmissions, (Mainship Pilot 34 Express with Yanmar turbo diesel 240HLA-STP engines). The local Yanmar dealer said to switch to motor oil, straight 30 or 40 weight. Hurth manual says to use ATF, dexron III or compatible. Currently they are filled with ATF.

I realize this borders on the which is better questions, blondes or brunettes or single engine vs twin engines but since Hurth has not replied to my query, I ask the group. Keep using the ATF or switch to motor oil?

If there is a thread on this question, I didn’t find it on the site.

Many thanks.

Ed Bougas

Claret/Pilot 34

 

[Alaskan Sea-Duction]

Welcome to TF Ed.

My advice is to follow the manufacture instructions. That way there is no doubt you are using the right oil.

 

[sunchaser]

My Hurth book says ATF. Why switch based on dock talk? This is more than a hair color switch.

 

[Tonic1]

Just went through this on my Pilot 34, same engines and transmissions, and decided to stick with ATF. I also saw quite a bit of discussion about this, but the manual that came with the boat, and updated ZF specifications found here

https://www.sbmar.com/articles/zf-marine-oil-specifications/

Call for ATF in our gearboxes and motor oil in others. I assume there is a reason for this. As a retired engineer, I know engineers are anything but arbitrary.

Brett

 

[twistedtree]

Attached is ZF's latest (I think) publication on approved oils for their gears. I think this is as up-to-date, and from-the-horse's-mouth as you can get. BTW, a dealer's or technician's recommendation I would count as one of the least reliable sources.

 

[DDW]

For saildrives, SF used to recommend ATF, and that's what the documentation shipped with mine says. However they had some problems with slippage, and changed the recommendation as a result. So there is some reason to check the most current recommendations for your transmission, rather that rely on the original docs or (as twisted tree suggests) a local dealer or technician who may not have the latest - or any - information.

 

[Comodave]

Go with whatever the manual calls for.

 

[Duetto]

we have 2 boats which both have zf's but different models. one uses atf and the other is straight motor oil. go with what handbook/zf says.

 

[Pete Meisinger]

Red ATF

pete

 

[Ski in NC]

Dexron ATF. Never heard of anyone recommending engine oil in a ZF63. Not sure what problem they are looking to solve. The 63 box has a pretty good rep. Using ATF.

 

[Alaskan Sea-Duction]

So I have CAT Twin Disc trannys. They, CAT, recommends the CAT TDTO 30 wt oil. This is GEAR oil, not motor oil. Not cheap stuff. I change it every year.

Again don't cheap out. Replace with what the manufacture calls for.

 

[Boat]

Modern motor oil is all about friction modifiers for fleet mileage and emissions requirements in over the road diesels. Go with a recent recommendation from the transmission manufacturer.

 

[Godabitibi]

ATF transmission fluid are very different than engine oil. They have more detergent and also better oxydation additives. It is also designed to keep hydraulic seals softer and have anti foaming additive to avoid air bubbles in hydraulic system. I would use ATF in any hydraulic operated transmission.

 

[rgano]

Do your trannies work well enough with ATF? If so, why change?

Do you want to try to figure out what the hell is leaking if you change the tranny to motor oil and then see some motor oil in your bilge?

 

[catalinajack]

So, some guy at a Yanmar dealer knows more than the manufacturer? Stick to the manual recommendation. Having said that, some transmissions, at least Borg Warner Velvet Drives, can run on either ATF or motor oil. Even with the BWs, the primary recommendation is ATF. By the way, ATF made to the Dexron III standard is no longer available.

We moved and I’m now doing most of the maintenance myself. Time to change the trans fluid and filters in my Hurth ZF 63A transmissions, (Mainship Pilot 34 Express with Yanmar turbo diesel 240HLA-STP engines). The local Yanmar dealer said to switch to motor oil, straight 30 or 40 weight. Hurth manual says to use ATF, dexron III or compatible. Currently they are filled with ATF.

I realize this borders on the which is better questions, blondes or brunettes or single engine vs twin engines but since Hurth has not replied to my query, I ask the group. Keep using the ATF or switch to motor oil?

If there is a thread on this question, I didn’t find it on the site.

Many thanks.

Ed Bougas

Claret/Pilot 34

 

[Simi 60]

Hurth manual says to use ATF, dexron III or compatible. Currently they are filled with ATF.

I can't believe the question is being asked.

 

[SteveK]

Have you looked at manual?
https://cdn.bakesonline.com/media/resourcelibrary/TransmissionManual_ZF45C.pdf

There are many oil experts that dismiss the original manufacturer recommendation because oils have evolved/ Like my lehman's no longer need to use straight weight, my velvet drive borg warners use the same as the engine.
I would agree if transmission rebuild shops suggest no need for ATF, there may be something there to consider.

 

[Easternshore]

question answered

Thanks for all of the replies, my original question was posed due to the local authorized Yanmar dealer telling me to use motor oil not ATF which I thought was odd thus my question to the forum.

I've always followed the manufacturers recommendations and wanted to be sure nothing had changed. Can't contact the original Mainship as it is gone and Marlow only wants to sell me a new boat.

Thank again to all.

 

[psneeld]

Manufacturer recommendation generally gets the nod.


I will say the assistance towboat I ran had motor oil in its tranny (Borg Warner) and its service life made trawler trannies look like they just sit on a shelf. They lasted decades too.

 

[BDofMSP]

My ZF 280a requires straight 30 wt. I personally would find the manual and use whatever that said.
BD

 

[Shrew]

My ZF 280a requires straight 30 wt. I personally would find the manual and use whatever that said.

My ZF30 takes 30W Heavy Duty (Diesel) oil as well. I also would suggest simply using whatever the gear set manufacturer recommends.

 

[Shrew]

https://www.harbormarine.net/pdf/zf-repair-manual-63a-80a-85a.pdf

Section 10: Automatic Transmission Fluid

This section lists all of the approved ATF vendors and products for a ZF 63A.

 

[Woodland Hills]

What makes a motor dealer an expert on transmissions?

 

[Bacchus]

https://www.harbormarine.net/pdf/zf-repair-manual-63a-80a-85a.pdf

Section 10: Automatic Transmission Fluid

This section lists all of the approved ATF vendors and products for a ZF 63A.

Here is the latest (AFAIK) 2019 ZF list of fluids.
The manual posted didn't list Chevron Transynd which is what I have used in my ZF 85 A. It is rather expensive synthetic but it's what is recommended by Allison and what I've used in my motorhome. One is Easier than 2 different fluids to keep some on hand if needed.

 

[magna 6882]

I went thru the same thing your going thru. The zf 04d lube chart is not real friendly to us manufacture. A lot of the approved lubricants, even castrol,have European approvals. After several emails they led me to mobile-delvac 1 ATF



https://www.mobil.com/en/lubricants...-duty-lubricants/products/mobil-delvac-1-atf/


I dont mess around with lubricants anymore. Its not like the old days.

 

[catalinajack]

Chevron Transyd and Mobil Delvac both meet the Allison TES-295 & 468 standards which far exceed the the outdated Dexron III standard. Fluids that meet these standards exceed all others. Delvac can be had from Summit Racing for $36/gallon. I just changed out the ATF in both the Allison in my pickup and in my 1999 Chevy Tahoe. I did a double exchange, that is, drain, fill, run, drain, fill in order to get most of the old fluid swapped out. Doing so for a Velvet Drive would take about one gallon.

I went thru the same thing your going thru. The zf 04d lube chart is not real friendly to us manufacture. A lot of the approved lubricants, even castrol,have European approvals. After several emails they led me to mobile-delvac 1 ATF



https://www.mobil.com/en/lubricants...-duty-lubricants/products/mobil-delvac-1-atf/


I dont mess around with lubricants anymore. Its not like the old days.