How to Check Transmission Fluid

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Albin

Veteran Member
Joined
Aug 7, 2018
Messages
50
Location
Canada
Vessel Name
Avalon
Vessel Make
Albin 40, trawler
I'm embarrassed to admit that checking the transmission fluid level is something I have done less than almost anything else on my boat. It's probably because the readings are so inconsistent. The manual for my Borg Warner velvet drive 1013 series transmission says check the dipstick reading "immediately" after shutting down the engine because oil flows back from the oil cooler after shutdown giving an artificially high reading. So that already sounds like a two person job because by the time I crawl back down in the engine room after shut down, the oil will surely have already flowed back from the cooler. So solo sailors can't check their fluid level??

For that reason, some people I know check the fluid when the engine is running and up to temperature. However, when I do that the reading is quite low and appears to be in need of oil.

Can anybody add some insight here? What is the best way to do this to get an accurate reading? Can I damage the transmission if the there is 1/2 quart over the full mark? I added some just recently because it seemed low but now I am second guessing that.

Thanks for any suggestions,
Jeff (Albin 40)
 
I used to have a problem measuring the level in my Twindisc because it required measuring while the engine idled. That resulted in unclear reading level presumably because of splattering. My suggestion is that you follow the manufacturere's direction once with a helper to turn the engine off. Once the level is correct, measure again with the engine on idle and again with the engine stopped for several minutes. Mark (measure) the dipstick, then decide which level to use going forward.
 
I'm embarrassed to admit that checking the transmission fluid level is something I have done less than almost anything else on my boat. It's probably because the readings are so inconsistent. The manual for my Borg Warner velvet drive 1013 series transmission says check the dipstick reading "immediately" after shutting down the engine because oil flows back from the oil cooler after shutdown giving an artificially high reading. So that already sounds like a two person job because by the time I crawl back down in the engine room after shut down, the oil will surely have already flowed back from the cooler. So solo sailors can't check their fluid level??

For that reason, some people I know check the fluid when the engine is running and up to temperature. However, when I do that the reading is quite low and appears to be in need of oil.

Can anybody add some insight here? What is the best way to do this to get an accurate reading? Can I damage the transmission if the there is 1/2 quart over the full mark? I added some just recently because it seemed low but now I am second guessing that.

Thanks for any suggestions,
Jeff (Albin 40)


This topic comes up once in a while. If you set everything up, one person can usually do it quickly enough to matter. I would say, have the dipstick loosened, have a rag handy, have the engineroom hatch open and the lights on. Run the engine for a minute to fill everything in the cooler circuit, then shut off the engine and zip down there, pull and wipe the dipstick, put it back in and pull out to verify the level.


Once you KNOW that the level is correct there is a great trick that makes it so you don't have to do that drill any more.


If you KNOW the level is correct, after the engine has been off for say at least 20-30 minutes, do a level check and see where it is on the stick. It should read somewhat high. Make a mark on the dipstick at that point. Then you can check for correct level anytime later without running the engine and you'll know its correct. (This method is actually described in one of my BW manuals)


Ken
 
Can you shut the engine down from inside the engine room either by pulling a solenoid coil wire (energize to run), or putting 12 or 24V to the solenoid (energize to stop), or by backing off a fuel bypass screw on the solenoid valve (some Cummins engines in trucks I used to drive years ago could do that), so you can check it instantly?


And I agree on putting another mark on the stick. Some old Caterpillar generator engines had fill/full lines marked "running", and another set marked "stopped", so you could check the motor oil with the engine running at speed. Same idea, applied to shut down and cold (overnight) or shut down and hot (10 minutes?), in addition to the OEM marks.
 
If you overfill it should spew out the vent.
You can also shut down then open hatches and start the engine put in gear for a few seconds then shut down and check the level.
If you delay checking for a few seconds it won't hurt anything.
That said I check mine cold.
I oriented my cooler so it does not drain back. Problem solved.
 
I did the drill described above on my BW drop center Velvet Drives. Now I look for the fluid to be about 1/8 inch above the fill line when cold.

I kinda doubt it's THAT critical but I do it anyway.
 
I did the drill described above on my BW drop center Velvet Drives. Now I look for the fluid to be about 1/8 inch above the fill line when cold.

I kinda doubt it's THAT critical but I do it anyway.

Well, the "OK" range is what 3/4? on the dipstick? So anywhere in there should be fine. At least this way you don't have to do the drill.
 
Thanks guys for the great suggestions. I'm still wondering though why I can't just check the fluid level when the engine is running? I've removed the dipstick from the transmission many times while the engine is running and there was no problem doing that although the reading while running seemed very low. I'm surprised the manufacturer didn't just calibrate the dipstick for that situation.
 
Thanks guys for the great suggestions. I'm still wondering though why I can't just check the fluid level when the engine is running? I've removed the dipstick from the transmission many times while the engine is running and there was no problem doing that although the reading while running seemed very low. I'm surprised the manufacturer didn't just calibrate the dipstick for that situation.


The input shaft and planetaries are always spinning and oil is flowing and flinging around in there when the engine is running in neutral so any check will be inconclusive at best. The dipstick is not in a "tube" so oil can get on any part of it while running.


Ken
 
Thanks Ken, that makes sense.
 
I have a different gearbox, a T.D. 506. I check it while running as that is T.D. specified way but I also next day, or at least after several hours, check it when shut down. That way any drain back has occurred and as long as the level reaches the same point on the dipstick there has been no leakage.
I still periodically check while running especially soon after an oil change. Then recheck the off level next day.
It works.
 
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