Westerbeke 20B/ JS Transmission

[AbelCMann]

Ahoy! Trying to do the right thing I checked the transmission fluid and found it didn't even register on the dipstick. I thought I would pump out what was in there, and put in fresh. What I pumped out, which was very little, looked more like transmission fluid than the 30W engine oil specced out by the manual. At any rate, I pumped out what I could and topped off with the specced oil. Shifts a bit more smoothly now - BUT - In neutral I can bring the revs all the way up, but when in gear I can now get no more than 1800 RPM, barely enough to make headway. This problem did not exist before - it ran great. That same day I replaced the fuel filter in the seperator unit, and cleaned out the bowl. SO… what's up?

[Strider34c]

AbelCMann, I am having issues with my Westerbeke 30b/JS transmission. Same case, previous owner had standard ATF in the transmission. I have a slightly different issue where as RPM's increase on the engine the prop shaft doesn't spin any faster. I plan to pump out the old fluid, fill with 30 SAE, cross my fingers and hope that solves the issue. Let me know if you had any luck resolving your issue and how you trouble shot it, I will do the same. Thank you!

[Strider34c]

No luck with the oil change. Pumped out the first quart, it looked like mud, no noticeable shavings in it. Poured in a fresh quart of oil, ran the engine slipping it into forward and reverse a few times. Forward still never caught for me. And then I repeated the process. The quart of oil I had just put in came out looking just as murky. Repeated the running and shifting and still no luck.
Contacted Westerbeke, no available JS Transmission replacements. Have you run into any options? They said Hurth, but that it is not easy. I have seen a few guys on here who went with the PRM 120, but I have not found one for sale in the US. I don't know how complicated the hook ups are.