ZF25 Transmission Dipstick / Fluid Level

Dean Gillies


To all Amel Owners,

I have recently had a failure event with my ZF25 gearbox. You can read about it further in Topic #41215 on this forum.  In that failure event, the dipstick for my ZF25 was damaged, and so I needed some means of checking fluid level until a new dipstick was delivered.

I then embarked on a very confusing 2 week journey of trying to determine independently where the correct fluid level should be in a ZF25 gearbox without reference to a dipstick. The results of this are very significant for Amel owners with ZF25 gearboxes.

Please note the following:

1. ZF Marine have informed me that ALL user manuals, parts lists, service manuals, brochures, marketing specs, website data etc for the ZF25 gearbox which state that the fluid capacity of the gearbox is 2.0Litres, are all incorrect.  

2. The correct fluid level for the ZF25 gearbox is 3.0L, but this figure only appears in the original installation drawing of the ZF25 (in Italian), which ZF sent to me and I will post on the forum files archive.  

3. Some owners will already suspect that it is really a 3L box because they will add 2.0L as specified in the manual, and then wonder why they needed to add another full litre to bring it up to the top of their dipstick. These owners have a "short" dipstick and can rest easy.

4. However, some owners will add 2.0l and find that its already close to the full mark on their dipstick.  If you are one of those owners then this message is addressed to you.

5. I know that some Amel 54 models have been supplied with an incorrect dipstick.  This dipstick is too long and reads "full" when 2 litres of fluid is present in the gearbox. These boats have been operating one litre short of fluid, which equates to a fluid level which is about 20mm too low.

7. I do not know who made the change of dipstick in the production process of these boats, but I can guess why they made the change, that is to try and match the disptick to the 2litre capacity widely published by ZF.

I urge all owners to check your dipstick against the following information:

If you have a dipstick with part numbers

3312-301-028 or 3312-201-002 

then you have the wrong dipstick and your ZF25 is at risk of damage due to low fluid level.

If you have a dipstick with part numbers 

3311-301-003 or 3311-201-001

then you have the correct dipstick and you will have the correct 3.0l of fluid in your gearbox.

If you have already experienced the failure and have replaced your gearbox with a new one from ZF, then you will most likely have the correct dipstick. 

Finally, as an absolute measure, the correct fluid level is between 84.5mm and 96.5mm from the mating face of the dipstick hole. 

I do not know if this problem ever affected SM production, but I do know that the documentation error from ZF was present in 2002. 

I am collating a private list of hull numbers which have been affected by this issue, and I would really appreciate if owners would email me privately on the email below

or simply post here on the forum.

I'd like to know your hull number and :

1. whether you have the long (incorrect) dipstick and if you've had transmission troubles,

2. If you have the short (correct) dipstick, have you renewed your transmission (or dipstick) since the the boat was delivered new.

Thank you

Dr Dean Gillies


AMEL 54 #154

+61 411 967106

trifin (at) soundthinking (dot) com (dot) au

Mark & Debbie Mueller



Sorry for all your troubles but thank you for your information.  My wife had me check the dipstick this morning.  Oddly, as many things on this boat seem to be, the part number on this dipstick reads: HSW 530 A1-HS 450A2.  After running the engine for two minutes and shifting from forward to reverse several times the oil level read full on this dipstick.  Absent the part numbers you referenced I measured the oil level at approximately 100 mm from the sealing face and added oil accordingly.  The transmission model is ZF25 2.0.

Mark & Debbie Mueller

Brass Ring  A54 – 68

Groegetown, S.C.