ZF Transmission Noise in Gear at Idle Speed

[Kraig Kirby]

We’ve got a 2010 Sundancer with QSB425 and ZF V-Drive transmissions, ZF 85 IV,  a noticeable noise started happening when in gear at idle and I’m looking for help with ideas of the cause.  I checked fluid levels, temps and pressures at speed and all seem to be normal and the port transmission has no noise.  The serial number on the unit is 30803-S.  I’ve got a video I’m trying to reduce file size to load, thank you in advance. Kraig  

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Bob Schmetterer

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[Kraig Kirby]

ZF Transmission Noise

I spent significant time and effort and wish I could tell you what finally resolved the issue.  I changed filters, fluids, I ran borescope down to look at condition of all gears, I pulled the boat and checked prop runout.  Upon doing all of that after a good 30minute run when pulling throttles back the noise was gone.  I’ve sampled fluid multiple times before, during and since and nothing has changed or thrown a flag.

[chiefengineer]

ZF Transmission Noise In Gear At Idle Speed

Good Afternoon,

I have been experiencing the same issues with my ZF68 with D3-220 engine.

Did anyone find the solution to resolve this issue?

[Ren Hoek]

I have the same chatter on my ZF 286A transmission.  When I bought the boat new 12 years ago, ZF came out and told me it was normal gear clatter.  They said as long as the noise goes away with a slight increase in RPM, don’t worry about it.  If I bump up the throttle by 10 to 20 RPM, the noise goes away.  After 1200 hours of use, the noise at idle is still there. I have never found metal in the suction filter nor had any abnormalities reported with oil samples.  It’s irritating but I don’t think it is a problem.

[sfranger239]

Same problem with a 220a

Even after a rebuild I am having the same noise that you are having. Any solutions. Props, shaft, coupler turned true to help rule out. 

[Kraig Kirby]

Thank you for the reply.  The idle speed is 650rpm, the fluid is full and we’ve found when accelerating the noise gets better.  We are going to sample the oil and check the filter for any metal.

 

[Clark Leighs]

what is the engine idle speed?       What is the Cummins spec. for the engine idle?

Have you tried to  bump the idle speed up by 50 or 100 rpm? What happens?  Noise worse or better?

Off to the side a bit but have you checked the gear box oil level and are you using the correct oil?

Use a digital tach or one of the handheld laser pointer digital tachs from Ebay or Amazon for about $20 to check the actual idle revs.  

Sometimes if the engine idle revs are to low there can be a clatter between the gears as they hit each other rather than a smoother contact.

 

Just my guesswork.

 

[Kraig Kirby]

Link to Video Short of the Noise

[Patrick Mangum]

Post to YouTube

Kraig,

Post the video on YouTube then copy and paste the link here on the forum so others can see.  I’ve had good luck with that in the past.  

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Kraig Kirby

[Author]

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