[C320-list] Hurth Transmission Fluid Replacement

[Warren Updike]

I second Alan's info. However, my dipstick has not a rubber "O" ring but a
thin metal washer that I have lost on numerous occasions. Knowing to look
for it has allowed me to find it.  I suspect that Alan's "O" ring is a
replacement for this washer.  
Dextron II ATF is appropriate for the Hurth gear. I'm able to find it in my
local auto store.
I use a small 3 oz. Listerine bottle to measure the ATF. These bottles I got
as samples from my dentist.  
When winterizing, I overfill the ATF to keep the clutches wet all Winter. In
the Spring, I pump out the excess.  
Yes, clean ATF is very hard to see on the dip stick. I painted my dip stick
with a white high-temp engine spray paint to make it easier to see the fluid
on the stick.
I've always sailed with the tranny in reverse to prevent free-wheeling of
the gears. I'd rather use neutral as that should produce less drag from the
prop.

Warren & Pattie Updike
1994 C320 #62 "Warr De Mar"


-----Original Message-----
From: Alan Goodman [mailto:goodmanalanlee at hotmail.com] 
Sent: Wednesday, March 30, 2011 2:11 PM
To: c320-list at lists.catalina320.com
Subject: [C320-list] Hurth Transmission Fluid Replacement


Frank - I have hull #67.  I have the Perkins engine / Hurth gear box combo
and changed my transmission fluid this fall.  IT USES ATF, NOT LUBE OIL.  I
used my oil dipstick extraction pump to remove all the old fluid through the
fill / level check fitting on top of the gear box.  Be sure to clean the
area prior to loosening the dip stick nut.  Also be gentle with the treads,
I believe the housing is aluminum (i.e. soft and easy to mess up the threads
of the harder dip stick steel threads.  Also, be aware there is a rubber 'O'
ring mounted at the top of the dip stick (don't loose it, but insect for
cracks and replace if necessary).  Also, I needed to 'fish' the suction tube
around inside the transmission case to get to the very bottom of the sump
... a good thing to do (IMHO) since the lube capacity is so small starting
with 'virgin' ATF would seem to be important.  You'll need a long tube on
the funnel to pour in the new ATF fluid without making a mess, at least 4
inches long.  Also, measure the fluid out before pouring into the tranny,
clean ATF is virtually impossible to see on the dip stick, so knowing you
are starting with the correct amount is a great way to make sure you do not
over or under fill (which the manual says is critical).  I don't recall the
specific type of ATF I used, but the bottle is on my boat and I'll be going
back to the boat in the next 2 weeks and can look if you like.  Lastly,
remember the ATF fluid level is checked without threading the dipstick into
the case, only resting upon the threads.  Contact me off list if you need
some more info or specifics.  BTW, I have the original install/shipping
placards, and one clearly instructs that when sailing with the engine off,
place the Hurth transmission in 'reverse' or 'neutral' AND NOT IN FORWARD.
I use neutral so as to allow my three blade cruising fixed prop to 'free
wheel' and minimize drag.  There has been substantial discussion herein
regarding the correct tranny position while sailing and other manufacturers
may have different instructions.  Let me know if you want me to photo copy
and send you the placard for your records (or maybe post in the technical
section of the forum?)  Alan Hull #67 Holland MI


> 
> Message: 9
> Date: Tue, 29 Mar 2011 00:22:11 -0400
> From: Amshd2 <amshd2 at aol.com>
> To: C320-List at Catalina320.com
> Subject: Re: [C320-list] Hurth Transmission Fluid Replacement
> Message-ID: <8CDBBE001866041-17B0-40FB0 at webmail-m136.sysops.aol.com>
> Content-Type: text/plain; charset="us-ascii"
> 
> 
> The Perkins with the Hurth Gear box in the 93- early 95 models uses
Transmission fluid.  I have hull number 30 with that set up.  Manual calls
for ATF Dextron II .
> 
> TONY 
> 
> 
> 
> > 
> > In a message dated 3/28/2011 3:35:30 P.M. Central Daylight Time, 
> > res07290 at verizon.net writes: 
> > 
> > 
> > I am planning to change the fluid in the Hurth Transmission this >
spring. 
> > Looking through the owner's manual I have for my 1994, The > recommended

> > fluid 
> > replacement is Type "A" transmission fluid. I can't find it at any >
local 
> > auto parts store. 
> > 
> > I have heard that Dexron III replaced Type "A", but I can't find > that
in 
> > writing anywhere. I called ZF Marine for advise, but have not > heard
back 
> > from them. 
> > 
> > Any ideas here?? 
> > 
> > All help is greatly appreciated. 
> > 
> > 
> > Thanks in advance. 
> > 
> > Frank Drahos 
> > Belles & Whistles #98 
> > 
> > 
> > 
>  
> 
> 
> 
> End of C320-list Digest, Vol 1067, Issue 1
> ******************************************