V-drve chatter Hurth - 95 330da 7.4

[capt steve]

when I had the boat surveyed before my recent purchase, the port engine made a very noticeable chatter when in idle speed. the trans shifted smoothly , didn't clunk , and when the rpms are brought up from idle , it disappears. the surveyor thought it was the engine being in poor tune and it also had a miss. I had the yard do a full tune / check the rpm with an external tach to make sure the idle wasn't too low. I was hoping that would cure it after some info I read. so it is still there , and basically the only other thing it could be is the flexplate at this point. is there any trans additive available that would quiet this down ? or should I plan on a trans job for next season?

 

[PMC]

Does the engine run smooth? Do you smell any fuel out the exhaust? Was a compression test done during the survey? Do you have any hesitation in pushing the throttles accelerating? What is the wide open rpm and speed? What is included in a full tune? What rpm is it running at idle?

 

[romanservices]

when I had the boat surveyed before my recent purchase, the port engine made a very noticeable chatter when in idle speed. the trans shifted smoothly , didn't clunk , and when the rpms are brought up from idle , it disappears. the surveyor thought it was the engine being in poor tune and it also had a miss. I had the yard do a full tune / check the rpm with an external tach to make sure the idle wasn't too low. I was hoping that would cure it after some info I read. so it is still there , and basically the only other thing it could be is the flexplate at this point. is there any trans additive available that would quiet this down ? or should I plan on a trans job for next season?

Mine chatter a bit at idle also, i have a slightly more aggressive cam in my 7.4's and was told that this may be the reason. They replaced both damper plates when my motors were installed. It does annoy me and I may have them checked again this winter.

 

[douglee25]

It's probably the damper plates. Does bringing the idle up to 1000-1200 rpms make it go away? If so, again, probably damper plates. The other contributing factor could be if there is a slight miss. I would do a fresh tune up - ie plugs, wires, cap, rotor and see if that corrects the problem. If not, see above. For what it's worth, almost 95% of the boats I've looked at in the past 3-4 months have had this identical issue. Most consider this normal.

 

[Island Time Buffalo]

Every V-Drive I'm familiar with in my boating circles, 2 of which were mine, chatter at idle. Like Douglee25 mentioned, it's the plates. There isn't (usually) anything wrong with them.

Mine chatter pretty boisterously until about 900-1000 rpms at idle.

They don't chatter much (or at all) when in gear though.

 

[Boater420]

My port engine also makes the same chatter noise when at idle speed. If I give it just a tiny bit more throttle it goes away. It does bother me as well but I haven't noticed it getting worse or effecting operation. I've heard it's normal from other 330 owners with v-drives and nothing to worry about. I've done the tune-ups, replaced spark plugs and wires as suggested by others on the forum but still the noise persists.

I wouldn't worry about it unless you notice it getting worse or effecting operation.

 

[Strecker25]

I might be way off, but I vaguely remember reading someone (maybe Frank?) saying the port drives run in reverse for the counter rotation and as a result make a chatter at idle. I might be making this up, so don't blame me if that makes no sense.

 

[CaptRonn]

SERVICE ADVISORY Date: 11/21/01 Advisory #SV2001-2 SUBJECT: Gear Rattle Hurth Reduction Gear Transmissions--- We have received a number of complaints regarding rattling or noisy ZF/Hurth reduction gears(V-drive or in-line). The noise is most pronounced at idle RPM and typically goes away when the engine RPM is raised above idle. Although the noise can be irritating, this is a normal condition with these transmissions that in no way affects the durability or reliability of the unit. In an effort to reduce the gear rattle noise at low RPM; the transmission manufacturer has suggested that we change from the current Dexron 3 transmission fluid that we use in the transmission to 15W40 motor oil. This is the same oil that we recommend for use in the engine and its higher viscosity helps dampen the contact of the gears and reduces the noise significantly. Indmar has started using 15W40 Pennzoil Marine Motor Oil in all reduction gears starting with engine IC985313. Those units will be identified with a Pennzoil 15W40 Marine Oil sticker on the transmission in place of the ATF sticker that was previously attached. We suggest that if you have a customer complaint of a noisy or rattling reduction gear that you replace the transmission fluid with 15W40 motor oil at the next scheduled service. Our current recommended maintenance schedule calls for changing the transmission oil at the first service(10-20 hours) and then annually or every 300 hours, whichever comes first. Since the transmission has no drain plug, it is necessary to suck the fluid out of the transmission through the opening in the bottom of the filter cavity. Use a suitable oil removal pump with a pick- up long enough to get to the bottom of the transmission housing. You might also want to remove the coolant lines and let the cooler and hoses drain into a suitable container to make sure as much of the fluid as possible is removed from the transmission. It is not necessary to flush the transmission, just get as much of the old fluid out as possible. Reconnect the cooling lines and fill the transmission with 15W40 motor oil. The level of the oil should be between the ìmaxî and ìminî marks on the dipstick. The following chart gives you the approximate capacities of the various reduction gears. Model Capacity450A 2.12 qt (2L)630A 4.2 qt (4L)630V 4.2 qt (4L

 

[douglee25]

Good info!

 

[capt steve]

thanks , that service advisory is spot on. it just blows my mind that they were allowed to do that. I suspect in 1995 , there were quite a few folks who just spent $250k on these 330da's that were like WTF????? I know I would have been! I will do the fluid swap now and at end of season. I figure three changes should get the complete unit swapped.

 

[Jandcinok]

Not unusual at all. One of ours chattered, did some research, changed spark plugs, rattle was gone. In addition to Captrons post, i found another from Hurth that said the reason was due to the tranny having straight cut gears, not helical cut.