ZF 63IV Chirp or "Ding" noise when changing direction of gears

[bluebelly]

ZF 63IV Chirp or "Ding" noise when changing direction of gears (UPDATE 4/19)

Hopefully somebody out there with transmission experience has seen this before. 8.1 horizons with 500 hours on them. Put the transmission in gear and all sounds normal. I hear the usual "clank" or "clap" that is associated with these transmissions. Now put the gear in reverse and there is a loud "chirp" or "ding" sound that is entirely different from what is normal. Now, put it back into neutral then back into reverse as many times as you like and it will sound normal every time. Now, put the gear into forward and that loud "chirp" returns just like it did when put into reverse. And, just like reverse, you can continue to put the transmission into forward as many times as you like and the sound is back to normal. So, in other words, this chirp or ding noise only appears when you change the direction of the transmission for the first time. I disconnected the shaft from the transmission at the coupler and the transmission will not make this chirp noise- it only does it with the shaft connected. The transmission sounds fine when running without the shaft connected. It sounds kind of like an electric drill running slowly. Oil analysis shows no problems with the internal condition of the transmissions. The fluid has been changed every 60 o 100 hours.

What do you guys think?

 

[Fred]

Loose prop or coupling?

 

[LG111]

I have a same set up as you. I experienced the exact chirp in reverse on first or second attempt then normal. Go foward normal go reverse maybe chirp but then normal. Ran the boat for two hours on a cruise and tried reverse, all normal no more chirp... a week later only had one reverse slight chirp. My guess is the change in temp with higher humidity and the chirp is a slight slip due to condensation on the plates.

 

[saopm]

I recall hearing the clutch plates can rattle at low speed. Perhaps with some this can cause a ding noise with an initial shift due to slightly different tolerances. Try calling ZF support to see if they are familiar with this symptom.

 

[fwebster]

Frequently, the source of an unusual ding or clank in the drive line is related to the prop becoming loose when the jam nut is run up against the prop nut and then both tightened together against the prop. The nuts back off and the prop is loose on the shaft. It can't go very far because of the cotter pin, but and distance leads to the prop working its way loose on the taper. The reason you only hear the ding once until you change directions is because the thrust of the rotating prop holds the prop in its new position. In reverse, the prop moves backwards until it contacts the prop nut; change to forward, and the prop moves back up the taper as far as it will go and stays there until you put the transmission in reverse again.

Play in the drive line is never good. Couple that with the propensity of the 340DA to snap off the prop end of the shaft at the strut and you have a situation that can quickly go from paying a diver $50 to tighten the prop nut and properly secure the jam nut to a new shaft, prop, nuts and a haul out ($2500 +).

This one is a "do it now; don't wait".

 

[Fred]

:smt038

 

[bluebelly]

Frank,

Thanks for you input. Checking the prop was on my list to check.

 

[bluebelly]

Well just got the boat hauled out and indeed the prop nuts were a little loose. Sure enough the nuts were installed wrong. The big one was up against the prop hub instead of the little one. Got them in the right order now and hopefully I got them tight enough this time.

 

[Georgia SeaDawg]

Outstanding! Well worth the price to be a part of this forum!!