Transmission Oil

[David Hopkins]

I want to replace and check the level of my transmission oil. I have a Universal M3-20 and I find the manual quite unhelpful.

Online manual is here: https://www.westerbeke.com/technical manual/200155_rev2_m12-m35_technical_man.pdf

Three issues:

1. The manual does not seem to say how much transmission oil I need. My plan is to remove the existing oil and I'd like to then put in the right amount of fresh oil. How much should I put in?

2. I'm not clear how the dipstick works. Photo below. First off, what are the markings for high and low? The dipstick is about six inches long with a score around the tube maybe a half inch from the bottom. If I'm keeping it in that narrow band it seems a poor design. When the oil level is low does it simply disappear? My second problem is it's a challenge to read the thing because it is black. I'm not sure any oil is on it at all.

3. Do I check the oil with the engine running or is it more like the engine oil where you check after running it?

 

[Stu Jackson]

David,

1. Don't know, keep checking, but see #2 below. By manual, do you mean the engine manual? If so, it won't have that info, you need the transmission manual. Try looking at the Hurth manual here: http://c34.org/wikiwp/?rdp_we_resource=http://c34.org/wiki/index.php?title=Manuals

2. Reading dipstick: roll it on a paper towel to see the amount. Almost all Hurth transmissions say to leave the dipstick not screwed in, just resting on the top of the hole, to take the fill measurement.

3. Nope: engine off, no need to even warm it up.

More tips & tricks here: Transmission Fluid 101 http://c34.org/bbs/index.php/topic,6417.0.html

 

[Jim 5757]

+1 to Stu's post. Engine off, pull stick & clean it off. Plug it back in but don't screw it in. A flashlight helps to see the oil on the stick.
I believe HBW50 takes about 0.29 pints of type "A" ATF. I think the info is in the engine owners manual...
If you can't see anything on the stick then you've got serious problems

 

[David Hopkins]

Thanks Stu, I had not considered the transmission was separate from the engine.

 

[njlarry]

Thank you again Stu. This forum is lucky to have you and Maine Sail.

My Hurth manual only specifies 0.5 l of "atf" but my Universal 25xpb manual specifies Dextron III in the instructions although it also has a table specifing 0.59 qts of ATF type A or Dextron II or III.

 

[chrisings]

Thank you again Stu. This forum is lucky to have you and Maine Sail.

My Hurth manual only specifies 0.5 l of "atf" but my Universal 25xpb manual specifies Dextron III in the instructions although it also has a table specifing 0.59 qts of ATF type A or Dextron II or III.

Type "A", Dextron II, III, etc. should all be reverse compatible. Type "A" is the generic name, Dextron the GM trademark. The fluid has been upgraded through the years as transmissions (read car transmissions) have become more complex hence the suffix II, III and so on. So in other words if a transmission calls for Dextron I, generally speaking, Dextron III should work fine.

 

[Damifudo]

The level should be right on the ring when it is properly filled. You can get a big syringe to suck out the old oil then measure and equal amount of new oil to replace it. I use mobile one oil to keep the heat down on the transmission. Heat is your enemy and the synthetics are better at reducing heat. I did a lot of research and Hurt approves synthetic.

. A well lubricated Hurth transmission is a happy Hurth transmission
You should run the correct lube oil in a Hurth mechanical gear. This means at a minimum Mobil1 synthetic ATF, not SAE 90 gear oil or the hydraulic tractor fluid you picked up for your Ford 8N tractor at Walmart. Better yet, upgrade to our Foley Hurth Hytork fluid and your Hurth transmission will last longer. For more information regarding the fluid please read Tech Tip #2, Marine Transmission Fluid. Regardless of the fluid you use, change it frequently and dispose of the old oil properly. For help and ideas in taking care of your old oil please read our Tech Tip #33, Disposing of Used Oil.