[C320-list] Question regarding transmission fluid

[Beau Black via C320-list]

Probably silly question; when checking the transmission fluid level do you screw the plastic gauge in or not?
Beau Black
#344
Sent from my iPhone

[Michael Stumpfoll via C320-list]

Do not screw in and be gentle. I think the replacement was around $50.
Thanks,
Mike Stumpfoll

On Oct 15, 2025, at 5:14 PM, Beau Black via C320-list <c320...@lists.catalina320.com> wrote:

Probably silly question; when checking the transmission fluid level do you screw the plastic gauge in or not?

[Dave Hupe via C320-list]

What engine did you have?  Helps to be clear since you get the correct answer.
For the Perkins M30, you just sit the transmission dip stick down without screwing it in. Pick it back up to read the stick (very hard to see the fluid especially if the fluid is new/fresh).
Dave Hupe 
1994 C320 #32

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On Wed, Oct 15, 2025 at 6:13 PM, Beau Black via C320-list<c320...@lists.catalina320.com> wrote: Probably silly question; when checking the transmission fluid level do you screw the plastic gauge in or not?

[Dave Hupe via C320-list]

Replacement of what Mike?

Yahoo Mail: Search, Organize, Conquer

On Wed, Oct 15, 2025 at 6:23 PM, Michael Stumpfoll via C320-list<c320...@lists.catalina320.com> wrote: Do not screw in and be gentle. I think the replacement was around $50.

[Michael Stumpfoll via C320-list]

The orange plastic top to the dipstick/vent. Age, heat, and oil turns the plastic soft. There is a guy that is making them out of aluminum, but i just bought a replacement Yanmar part hoping they have better plastic. But if the first one lasted 25 years, the replacement should outlive me. It is a clever design, the hollow tube allows the transmission oil to expand and vent out of the small hole in the plastic top.
Thanks,
Mike Stumpfoll

On Oct 15, 2025, at 5:46 PM, Dave Hupe via C320-list <c320...@lists.catalina320.com> wrote:

Replacement of what Mike?

[Bob Wyllner via C320-list]

Going back to the original question, I have read conflicting information on whether the cap should be screwed in or set on top to properly measure the level on my 3ym30.

Historically I measured by setting on top, but more recently I’ve measured by screwing in all the way based on the fact that much of the mixed researched leaned more towards that direction. (The transmission owners manual that I found on line did not cover this unfortunately. Mine is a Kanzaki / KM2P-1)

I be interested to see what others are doing.

The other challenge as we are all no doubt painfully aware is being able to see the level on the dip stick so clear is the oil. :)

Bob Wyllner. Hull 1039

On Oct 15, 2025, at 7:20 PM, Michael Stumpfoll via C320-list <c320...@lists.catalina320.com> wrote:

The orange plastic top to the dipstick/vent. Age, heat, and oil turns the plastic soft. There is a guy that is making them out of aluminum, but i just bought a replacement Yanmar part hoping they have better plastic. But if the first one lasted 25 years, the replacement should outlive me. It is a clever design, the hollow tube allows the transmission oil to expand and vent out of the small hole in the plastic top.

[Dave Hupe via C320-list]

I think I read a tip somewhere to spray paint/coat the dipstick (cleaned very well first) with a white heat resistant paint that makes it much easier to see the level of the red trans fluid. I have not done it so still struggle trying to evaluate the level on my Perkins engine (Hurth transmission). 

Dave Hupe 
1994 C320 #32

[Brian McLamb via C320-list]

I have always screwed it back on gently. No need to secure like you were
preparing to motor away. Agree that a flashlight is needed to see the oil
sheen on the dip stick

S/V Serenity #1075

Brian McLamb

[Michael Stumpfoll via C320-list]

In the yanmar service manual chapter 10 it says “when checking the oil level with the dipstick do not screw in the oil filler screw; it should rest on top of the oil filler hole”

This can also be verified the next time you sick the oil out and replace it with the measured amount.

This is also consistent with every other screw in type dipstick I have come across. Screwing it in is to secure it, not to measure it.

Thanks,
Mike Stumpfoll

On Oct 16, 2025, at 11:21 AM, Brian McLamb via C320-list <c320...@lists.catalina320.com> wrote:

I have always screwed it back on gently. No need to secure like you were

[Bob Wyllner via C320-list]

Thanks for the input folks! Good stuff!

On Oct 16, 2025, at 11:56 AM, Michael Stumpfoll via C320-list <c320...@lists.catalina320.com> wrote:

In the yanmar service manual chapter 10 it says “when checking the oil level with the dipstick do not screw in the oil filler screw; it should rest on top of the oil filler hole”