Marine Transmission Fluid Filters

To add extra life to your Borg Warner transmission are there any externally mounted filters that could be used to clean the fluid and add to system capacity ?? Is it worth It ?

When I rebuilt mine an old timer repair guy that did a pressure test told me to rotate the cooler so the fittings were oriented straight up. That way more oil would stay in the system and thus run slightly cooler. I had to add 90 deb fittings to do that.
No filter though. There is a magnet epoxied to the case bottom that didn't show on the repair diagram. That catches steel particles of any.
I didn't do it at the time but I think maybe a course filter on the return line might be nice.
However thousands in service with no filter.

Ron T said:

To add extra life to your Borg Warner transmission are there any externally mounted filters that could be used to clean the fluid and add to system capacity ?? Is it worth It ?

Click to expand...

It' should be pretty easy to add a hydraulic filter to the cooling loop and it might help a bit. But in trawler service at least, one can expect 4-5000 hrs out of a reasonably maintained Velvet drive. At that level, I personally don't think it's worth it.

https://www.hopedirect.com/product/...ssure-filter?gclid=CK-wt7K_ks4CFU0jgQodbSQMDg


Ken

In a transmission such as BW what are you wishing to filter out ?

We have a Twin Disk transmission. The spec is for 30 wt oil. The factory rep told us to extend the life of the transmission, use
30 wt NON detergent oil. Available from NAPA. It does not foam like normal 30wt oil and in turn provides better lubrication.

Be carefull.
You must know the gear and how the oil circuit is arranged. Some newer gears have an actual filter, spin on, installed but it is in a low pressure part of the circuit so a spin on can handle it.

Many gears run at quite high pressures and will blow a spin on apart.

Many T.D. gears run at ~ 300 lbs. or more. There is no access to a low pressure part of the circuit. The only access is the gear oil cooler circuit which is under full operating pressure.
T.D. recommends a filter that can withstand 500 psi as the gears can spike apparently.



Change the oil regularily and most gears will do just fine without a filter.


I did install one last year because I had a suitable filter, a cast off from a job, kicking around for ~ 20 yrs. and finally decided to use it. But it would have cost me over $500 if I had to go out 2 yrs ago and purchase. Then add the proper hydraulic hose and fittings.

I don't know about the B.W. units but be carefull about what you are looking at and choose carefully. Be sure you understand how your gear operates.

Folks looking for non detergent oil can check with motorcycle shops.

Also used in trannies and for 2 stroke bikes as lube oil.

Our Twin Disc tranny requires 50 wt , takes some looking.

gaston said:

In a transmission such as BW what are you wishing to filter out ?

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Steel/iron will eventually get stuck on the magnet.
In MY situation, I decided to take mine apart off season for a PM rebuild.
The fabric clutch material had started to come apart and a filter would have caught that debris.
Whether or not that would have eventually helped is a matter of theory.

Probably helps little to add a filter. This is not like an auto trans constantly changing gears causing the clutch material sees a lot of wear.
I rebuilt my velvet drive due to a leak. Leak caused by rust on a cast iron face, so the rubber square ring lost its seal.. Clutches were like new and this is an old boat.

A magnet maybe epoxied on the inside not a bad idea. But you cant see it, if there is metal circulating.

Dont some velvet drives have a filter screen on an oil line fitting?

This is from my BW repair manual. Item 94 is a strainer. sdowney717 you have a good memory!

jleonard said:

This is from my BW repair manual. Item 94 is a strainer. sdowney717 you have a good memory!

Click to expand...

Hi, I had remembered rightly.

Another consideration, an inline oil filter must be able to bypass. If it did not, the line pressures would drop if the filter slowly clogs, and that would cause low pressure on the clutches, which will wear them out sooner. Maybe a reasonable filter is instead of a full flow filter, using a bypass bleed stream filter. That way full line pressure to clutches will always be there. The bleed stream filter has a tiny hole that bleeds off oil flow to a filter, then dumps it back into the sump.

Some engine oil filters do have a builtin bypass which would be ok I think so to use an add on filter head. A standard auto engine oil filter would work ok for trans fluid and simply put in series with the oil flow.

If you want to do something meaningful and inexpensive, just change the oil more frequently. My big ZF holds about a gallon. That's $13, peanuts. If you changed it every time you changed the engine oil, the additional oil would be cheaper than any pressure filter you could buy, regardless of how long you owned the boat.

Ted