Transmission Slow Reverse

[sander06]

I've got a hurth 100? transmission on my Westerbeke W21 that has some transmissions issues. It goes into forward instantly, but when shifting into reverse, it sits there for maybe 10 seconds before engaging. Once engaged, it works fine. If I shift into neutral and then back into reverse, it agains instantly engages. However, if I shift into forward and then try reverse, it has the same hesitation to engage again. The tranny fluid looks good and is at the proper level. I can't quite visualize what's going on inside the transmission, but it's like something is just getting stuck. Any ideas? The PO had the tranny rebuilt about a year before I bought the boat.

Coming into the dock at the marina we're staying at for the winter here in Punta Gorda I managed to take out a dock box with our bowsprit for lack of the instant reverse. Of course, it didn't help that I had a howling wind at my back, 12,000# of boat moving forward, two dock hands with their collective heads up their posteriors, and me docking for the first time with our new to us boat!! So now I own a slightly damaged dock box.

I plan on draining the tranny and putting in new fluid and seeing if that helps. I'm not optimistic, however. I hate working out the bugs on a new boat!!!

Cheers

[Rockter]

Sander :

Disconnect the gearshift cable from the gearshift lever and check firstly that the lever on the gearbox will engage reverse readily, then check that your cable is not sticking or dragging.

Gears should not hesitate like that. They normally engage instantly.

If the cable is dragging, then try lubing it. I find that WD40 works well for me. I have never known a cable to stick that has been lubed with WD40, and that includes quite a few motorbikes.

[sander06]

Thanks for the suggestion, Rockter. Unfortunately, that's not the cause. It's internal to the transmission which usually means $$$$$$! I'll change the oil and see how things go.

Merry Christmas from Punta Gorda!

[Rockter]

I trust that it is one of these hydraulic things that does not mesh directly?

10 seconds is a long time lag.

[rcarr]

There is a toubleshooting procedure in the Hurth manual for delayed engagement, which I have used for a Hurth 150.

Drain oil and replace with one quart of diesel

run engine for 3 minutes in idle while engaging forward and reverse at 10 second intervals

stop engine and drain diesel

fill transmission with fluid



Rodger

[chucklesR]

I had the same problem with my Westerbeake 30b's tranny. The shift level operates a valve which then engages the gears hydraulically. The transmission is a sealed unit and not repairable in the field. Fortunately mine was covered by the warranty.

If yours is similar to mine replacement is the only option, it will get worse over time.

[timebandit]

So, when did it start?

[sander06]

Thanks for the comments. I've contacted the PO to see if he can suggest anything. I only recently purchased the boat that hadn't seen action for a year being stored on the hard, so it may be just the fact that it sat for so long. I trust, implicitly, that the PO would have told me about the problem had it existed prior to purchase. I think that hydraulic transmissions were developed to make the rest of us mortals look stupid! I know a lot of stuff, but the inner workings of this thing are an absolute mystery to me!!!

Carry on!!

[joethecobbler]

The Hurth hbw100 or zf10(m) is not a hydrolic transmission. It is a Mechanical gear with clutdh disks and ball ramps that are mechanicaly engaged when you shift from neutral to forward or reverse. If the cable and linkage is working and properly adjusted ,the problem is that the clutches and or thrust washers are worn ever so slightly and that wear is why there is a delay in engagement. the tranny slipps until it heats up the disks enough to grab , and away you go.
I also have a Hurth and suffer the same problems w/ engagement. Definetely inconvenient when approching obstacles under power not knowing if the trans will engage.
The "fix" is actually only a matter of replacing the wear items (friction disks-8 , and 2 thrust washers) Of course the rebuild will cost $6-800.00 and a "new" transmission is $1000.00- $1400.00 . If your into do-it-yourself you can buy all the parts you need online for around $3-400.00 of course you'll need a press and some good guages to re-assemble correctly as the end play in the output shaft and the spacing of the gears and clutches is the critical issue affecting the longevity of the transmission. I got 400 hours out of it the last time , I put 4 clutches and 1 thrust washer in it in at the dock in Bucksport SC, and made it to Daytona Beach before it began slipping again.
I blame poor assembly and lack of attention to gear spacing, as I didn't have a press or guages to work with.
I'm very interested in what you will choose to do rebuild or replace. I am looking for a spare trans to rebuild and keep on the boat when cruising.

[captbillc]

my friend has a yanmar 3GM with a kanzaki tranny (very similar to the hurth) . several years ago it would not go into forward some of the time. i took apart the tranny and checked it over. i put the reverse discs in the forward clutch & the forward discs in the reverse. all it cost him was for seals & gaskets . the tranny worked fine after that.