TMC 40 Gearbox

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BigStu

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Hi all

I have a Beta 25 with TMC40 Gearbox on my Cobra 850. Went for a shake down sail yesterday and noticed a 'whistling' noise coming from engine. Ran in neutral and vanished so is gearbox or shaft. Does not seem to be shaft noise so I think the gearbox is culprit.

Sound is more a whistling than a whine and occurs at most speeds, coming on gradually after you change revs. Also noticed Gearbox oil is overfilled above second mark on dipstick, oil is also very dark- but unsure when it was last changed.

Anyone experienced this or know what it is?
 
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Morning, I have a similar problem and the same gearbox, I would start by changing the oil if its dark and yo the correct level, mine seems yo be between 1000 to 2000 revs then goes, changed the oil on mine twice last year just to be sure but made no difference but my oil was not dark, I them came across an article about sharp edges on the prop, mine was quite new so when the chance came to get St it I carefully rounded the edges... Guess what no difference, was motoring back to the mooring when I picked up a lump of floating weed which stopped the noise for a bit, next step is to check engine alignment I think but am starting to clutch at straws a bit, when back out and will check shaft wear, anyone with any suggestions I'm sure we would be great full, have checked cutlass bearing and all seems good.
 
BigStu said:
Hi all

I have a Beta 25 with TMC40 Gearbox on my Cobra 850. Went for a shake down sail yesterday and noticed a 'whistling' noise coming from engine. Ran in neutral and vanished so is gearbox or shaft. Does not seem to be shaft noise so I think the gearbox is culprit.

Sound is more a whistling than a whine and occurs at most speeds, coming on gradually after you change revs. Also noticed Gearbox oil is overfilled above second mark on dipstick, oil is also very dark- but unsure when it was last changed.

Anyone experienced this or know what it is?
Click to expand...

Check that you are measuring the level correctly. If the dipstick is the screw-in type, it probably needs to be rested on the top of the thread rather than screwed in to check the level ...... but this is not always the case so the manual needs to be consulted. :)

Richard
 
Again stating the obvious, why not give Beta a call, I have always found them helpful? If nothing else they can pass on a number for Tecnodrive in Italy and then speak to them direct, language is unlikely to be a problem these days.
 
Hi, yes was one of the first things I adjusted but still the same... Will check alignment and sterngear ect. May try a spacer to see if the shaft in a very slightly different position makes any difference failing that when out for the winter check it all out.
 
Prop noise?
We too have beta 25 and tmc40p box- making lots of clunking noises mid revs- gradually worsened to point where box is off- play and grinding noises when spinning manually!
Not picked up anything previously- I've looked at fluid and I used AGM (it's dexron 11 type) not called ATF- anyone tell me if it's the same - hope that didn't cause the problem. Cable adjustments seem fine too.
Sorry to slightly hijack the post but same set up! Thanks.
 
Scomber said:
Prop noise?
We too have beta 25 and tmc40p box- making lots of clunking noises mid revs- gradually worsened to point where box is off- play and grinding noises when spinning manually!
Not picked up anything previously- I've looked at fluid and I used AGM (it's dexron 11 type) not called ATF- anyone tell me if it's the same - hope that didn't cause the problem. Cable adjustments seem fine too.
Sorry to slightly hijack the post but same set up! Thanks.
Click to expand...
Sorry not AGM---AQM fluid!!!
 
Not on my bottle my friend!! AQM writ large- NOWHERE does it say ATF- small dexron 11 on back. If I could send you a lovely piccy I would. Thank you though.
 
Strange. AQM seems to be a registered trade mark. Registered by whom is unclear, as is its meaning, if it even has one. (There are all sorts of other non-registered meanings of AQM, but I doubt it's anything to do with, for instance, Advanced Quantitative Methods.)

It's an ATF, of a particular formulation. And obviously a state secret ;)

P.S. Dexron II, as originally formulated, had some issues. I presume AQM and other later equivalents, address those without discarding the benefits.
 
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