transmission dipstick missing its gasket

[sailinggreg]

I've haven't seen this posted anyplace else.

I had a mechanic onboard for for some other repairs and had him do the annual maintenance as well. He noted that the transmission dipstick is missing its gasket. I sort of said, well its never leaked. He explained that the gasket doesn't just keep it from overflowing but that its important for the transmission to engage.

He kept saying without the gasket you're missing two threads. As I understood what he said, inside the transmission fluid reservoir, at the very top is where the transmission engages. He showed me the threads on the dipstick and how without the gasket it would fit lower on the reservoir. I guess just that little bit can make a difference(?).

My questions:

1/ can anyone confirm this and maybe explain it to me better?

2/ anyone know the part number for just the gasket?

3/ where to buy it?

I have a 1980 Ericson 30+ with 5416 Universal Diesel engine. I believe that means it has a Hurth transmission(?).

I'm in East Bay of San Francisco (Oakland).

Thanks!

Greg

 

[Loren Beach]

I wonder if that "gasket" is a soft aluminum one? i.e. I am unsure how well it really seals the opening. If there has been AFT appearing around that plug, I might replace it with a bonded washer.
Also, the oil level (actually ATF) in that Hurth is measured by dropping the plug with attached dip stick down but not screwing it in/down. The presence of a washer would not make a difference, AFAIK.

 

[Prairie Schooner]

I've haven't seen this posted anyplace else.

I had a mechanic onboard for for some other repairs and had him do the annual maintenance as well. He noted that the transmission dipstick is missing its gasket. I sort of said, well its never leaked. He explained that the gasket doesn't just keep it from overflowing but that its important for the transmission to engage.

He kept saying without the gasket you're missing two threads. As I understood what he said, inside the transmission fluid reservoir, at the very top is where the transmission engages. He showed me the threads on the dipstick and how without the gasket it would fit lower on the reservoir. I guess just that little bit can make a difference(?).

My questions:

1/ can anyone confirm this and maybe explain it to me better?

2/ anyone know the part number for just the gasket?

3/ where to buy it?

I have a 1980 Ericson 30+ with 5416 Universal Diesel engine. I believe that means it has a Hurth transmission(?).

I'm in East Bay of San Francisco (Oakland).

Thanks!

Greg

Do think he's saying that without the gasket the dipstick does not register the amount of fluid correctly? When I first read your account I thought it meant that the proper penetration of the plug threads was necessary for mechanical engagement, somehow.

 

[Smixon75]

A couple of years ago, we noticed our Westerbeke 44B4's transmission dipstick bonded seal was missing. We purchased a set of metal bonded sealing washers from Amazon. Please forgive me as I can not remember the size but I think it was 12mm, but we found a perfect fit in the kit listed below. We did not have a problem with the transmission engaging or disengaging, just slight leak around the cap. This solved the problem!

https://www.amazon.com/gp/product/B07QBNR7B4/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

 

[Loren Beach]

On the subject of "bonded washers" here is my earlier comment:

O34 - Hurth 17 mm Drain Plug washer

I just spent some tedious hours changing out the old ATF in our '88 Hurth model 50 trans. The top where the fill/dip stick fitting lives is visible only when both bolts that hold the heat exchanger bracket are removed and the HE is moved slightly...

ericsonyachts.org

You should be able to find the size needed, by contacting a local supplier, probably located in an industrial area of the city. Take the dip stick/plug with you to be sure of sizing.

 

[sailinggreg]

Do think he's saying that without the gasket the dipstick does not register the amount of fluid correctly? When I first read your account I thought it meant that the proper penetration of the plug threads was necessary for mechanical engagement, somehow.

Hi Prairie Schooner,

You read it right the first time. The mechanic was definitely saying a gasket is necessary for mechanical engagement. Not just a matter of filling the right amount.

It surprised me, that's why I asked on here. Now I'm surprised others aren't confirming it. Mechanic is well respected in the area.

 

[sailinggreg]

Thanks everyone for your replies,

Fyi, its a gasket on the dipstick, not on the plug. And I've never noticed the transmission leaking. Like I say the mechanic said its needed to make the threads line up when you do screw in the dipstick. (Yes, I know to check the level you insert the dipstick but don't turn it.)

I called Pacific parts distributor. Of course, they want to know the model of the Hurth transmission. Anyone know? They said there should be a metal tag on it with the number. I'll be onboard tomorrow to look for it. All the years of checking the transmission fluid I've never noticed a tag but its probably covered in grime.

If that doesn't work, I'll follow Loren Beach's suggestion and take the dipstick with me to try to get a gasket that works. Sounds like metal/aluminum gasket is the way to go.

Thanks!

 

[Dave G.]

If original should be a HBW50 I believe. Always good to check it though as could have been replaced by a PO

 

[sailinggreg]

If original should be a HBW50 I believe. Always good to check it though as could have been replaced by a PO

Dave G. - thanks! It sure looks like that one. Good advice though. I've been fooled before by things I thought were original but were replaced by a PO.

Thanks again!

Greg

 

[Prairie Schooner]

Hi Prairie Schooner,

You read it right the first time. The mechanic was definitely saying a gasket is necessary for mechanical engagement. Not just a matter of filling the right amount.

It surprised me, that's why I asked on here. Now I'm surprised others aren't confirming it. Mechanic is well respected in the area.

Wow, that sounds really weird. I'm trying to imagine how that would work, or even make any sense as an engineer designing the device. The difference can't be much more than .100", for something that's repositioned with some regularity. Is there an exploded view available of this gearbox? - Jeff

 

[Kenneth K]

He kept saying without the gasket you're missing two threads.

Actually, the opposite would be true--with the washer you'd have fewer threads engaged ("missing threads"). Without the washer, more threads are engaged as the dip-stick is screwed further into the reservoir.

Obviously, this guy misunderstood something that someone once told him, probably long ago, and he's never since thought to question what he was told. The misunderstanding possibly comes from the fact that if you insert the dipstick in a mis-aligned fashion while the engine is running (even with the transmission in neutral) the tip of the dipstick can collide with internally rotating gear(s). I did this once and have a dent in the end of the dipstick to prove it. However, once the dipstick threads are seated into the body, proper alignment is ensured.

A similar interference might be possible (on this, or other transmissions) if someone were to insert the dipstick too deep into the transmission case. But, there is almost NO way that 1 or 2 thread depths of engagement could make enough difference.

 

[bgary]

Huh. now I'm confused (not unusual, given currently-insufficient quantities of coffee...)

My dipstick has a groove which (I've always assumed) is used to indicate correct fluid level.

Am I now to believe there is supposed to be a gasket (or O-ring) in that groove?

For reference, my dipstick has a washer when installed, and I check fluid level with the washer on the dipstick and the dipstick *not* threaded into the transmission casing.

 

[Kenneth K]

No, Bruce, you're good. The groove at the bottom is for checking fluid level (no o-ring).

I think the confusion is just semantics. Some call the "ring" (where the dipstick screws in) a gasket, and some call it a washer.