V Drives Transmission Rattle

mquiet

Well-Known Member
Aug 4, 2009
1,500
North carolina
Boat Info
1999 480 Sedan Bridge
Engines
Caterpillar 3196
I did a boat survey yesterday. Both the surveyor and I noticed a rattle sound coming from the port transmission. The mechanic and the broker both said it was just tranmission rattle that is normal with the V-drives. Is this true?
 
Yes it's true. Very common for the drive plate to rattle when it is not under load. If the noise goes away when you put it in gear and you give it a little throttle, I wouldn't worry about it. Mark
 
I had a V-Drive rattle that increased over a short time. It turned out to be the rubber dampers that are located on the front of the trans between the trans and the motor.
ZF pulled the V-Drive off the motor to replace the plate that holds the rubber dampers. They act as a shock absorber between the motor and the V-Drive.
 
Change your spark plug wires. This is the most common problem with rattling in V-drives. Without going into to much detail, when your wires are not in perfect shape, backlash occurs during each revolution. This creates a little rattling noise in your V-drive. More annoying then anything else. I am sure a few others will chime in with better details.
 
I would favor the surveyor's thoughts on that rather the broker, or the mechanic if you selected them and not the broker... If it was only at idle and below 1000 RPM then I would think that is resonable.. What type of V-Drive was it?

I have the Hurth V-Drives on our boat. My port transmisson rattled something terrible at the start of the season. The starbord is quiet as could be all you hear is prop wash. I posted a similar question and this is pretty normal for my model. I was told here that there are dampening plates that are held together via springs over time the springs tension reduces causing the rattle.

One thing to consider is the fluid level, when you check it you have to turn the T handle to loosen the plunger in the V-Drive, you should get a rush of air. When you replace it make sure its snug and tight. I never realized this, once I had the stick back in tight the sound was greatly reduced.

I also believe that in my case ambient temperture plays a big role. When it colder in the spring and fall the noise is much more noticable, summer its not...

Our third outing we had an issue with the port transmission going into gear. I read the manual and realized that they recommend while warming up the engines on my model transmission to turn them at 1100 RPMs for 2 minutes to let the hydraulic system charge. Been doing that now and no issues...

Can't explain it but yes the V-Drives make noise and the Hurth model does have the rattle. I believe mine are Hurth 630A...
 
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It is what the others have said, if it goes away with a slight increase in RPM it is "normal" but could be an indicator that the engine may need a tune up (cap, plugs, rotor, and wires),this usualy corrects this issue. As long as it goes into and out of gear quickly and the noise goes away at higher RPM's (check fluid level and smell), you should be fine.
 
The temps were identical in both transmissions at 90 degrees. Sound was not noticable while underway, but with the hatch up...what a noise. Mechanic said it was normal, but surveyor was not sure. Got to love the differences in opinion.
 
if the noise goes away when drive is in nuetral and sound is really loud, when in idle forward or reverse, then drive plate needs new springs.
This is not cheap. requires motor removal part is bout 2-300, labor is the killer to either remove motor or to remove vdrive both take about same labor
HAd the same thing my drive plate had 2 springs missing. check against other motor does it sound the same? if so may need a tune up . usually both plates won't go bad unless the boat took a bad hit. If you pm me I have a movie file i can email you that my surveyor took when he was documenting the issue.
 
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Drive noise was only heard at idle. I am going to do another check prior to final purchase. Sounds like I just need to engage engine and add a few hundred RPM. Transmission did shift smoothly.
 
The noise should go away with only about 100 RPM increase (in gear).
 
Straight Hurth drives here, same issue but only on the port engine. I did a full tune up this spring and rattle didn't go away. Only occurs at dead slow idle and I jack things up to about 850rpm and it goes away. My fluid is clean and full. I was wondering if the direction of the rotation makes a difference (?) I have twin LH engines so one of the transmissions runs in reverse.
 
if the engine is out of tune, the low speed running will cause the engine to turn eratically causing the noise.The dampers (drive plate) springs are supposed to reduce this when the engine gets to speed the the noise should go away because the faster the rpm, the more less fluctuation. if you hear noise, either engine has an issue or drive plate is bad. On my boat I had one drive plate that had 2 broken springs, and the other engine, I had a carb starving for fuel, a carb rebuild fixed that issue

hopfully your issue is the latter. if you are purchasing. it may be worth your time/and or money to have a mechanic you want to fix the boat do a quick inspection. I got the seller to give me a 2500 credit towards the repair. perhaps you may want to do the same based on surveyors reccomendations
 
I am going to have another mechanic take a look. I don't think seller is going any lower. I broke through to a great price (which I will disclose after purchase).
 
My 310 DA 2000 does the same on the port engine only and two different mechanics said that it was normal the're is no rattle under load and they shift really nice!!
 
reason they don't rattle under load is that the drive plate is only needed at low rpm to control vibration at high rpm damper is not used the drive plate locks in without use of springs
 
What is the average cost to replce th damper plates on a Searay 460 w/ twin cummings engines & ZF vdrives?
I'm told the engines need to be removed as there is no room to remove the trans.
Any Ideas?
There is black rubber coming out of the bell housing vents 7 a terrible clatter!
 
It is normal. Mine does that at idle speed in gear but as soon as i give it just a touch of throttle it goes away. It also goes away after about 10 min of runing time aswell. I have been told this from numerous people and a merc certified tech.
 

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