Should I strip the gearbox?

Ruffles

Ruffles

Well-Known Member
Joined
26 Feb 2004
Messages
3,046
Location
Boat: Portsmouth, Us: Stewkley
www.soulbury.demon.co.uk
Last season we noticed a rumbling noise when the engine was in gear. I suspected the gearbox. It's a VP MS2A-D. When I checked the oil level it was fine but the oil was suspiciously dirty. Now I've been a bit lazy changing the gearbox oil - probably not been changed for 18 months - but then it has not been used much. Anyway, I changed the oil (twice). The rumbling was still there after that - though it may have been less loud. Hard to be sure.
Now that the boat's out of the water I can see that the cutless bearing is shot. Caused I imagine by calcification on the shaft.

ShaftCalcification1.JPG


Is this likely to be the cause of the rumbling? What I don't want is to discover the noise is still there after the bearing is changed and the boat's back in the water.

How easy is it to strip one of these gearboxes? Where do they usually fail?

Also, if I have to, how safe is it to remove the gearbox with the boat in the water?
 
the gearbox oil should not be dirty and it shouldnt use any oil either. suggests you have a seal or bearing failing, even if the noise is more likely to come from your shaft.

the box is simple and easy to strip as long as you dont force things. bear in mind that once stripped you will need to check for wear on the splines and possibly end up replacing some bits.
 
[ QUOTE ]
the box is simple and easy to strip as long as you dont force things. bear in mind that once stripped you will need to check for wear on the splines and possibly end up replacing some bits.

[/ QUOTE ]
I presume I'll need to invest in a gasket kit? Not a small expense in itself. Is it possible that the control needs adjusting? I presume the gears engage using some kind of clutch.

How far back does the box need to travel to clear the engine shaft? With the boat in the water I 'll have to slide the shaft back.
 
[ QUOTE ]
Check that the drive plate between the engine and gearbox hasn,t got worn spring seatings (if it has them).
My transmission used to go Garumpagrumblecarumpagrumble-----
After I changed the drive plate it goes Purrrrrrrrrrrrrr!!.

[/ QUOTE ]
Which bit is the drive plate? See link to the exploded parts list in the OP.
 
OK I'm a cheapskate, but for myself I would buy replacement bearings from a bearing factor, lip seals from the same place O rings ditto and either make up my gaskets from gasket material or or more likely from cornflakes packets. After all, the gearbox isnt pressurised and provided I removed the old gaskets with care it shouldnt be too difficult to cut out new ones. I'd have to use common sense about this (eg mic gasket thickness etc). But in your case since you've never done the job before, its best to buy the official Volvo bits.

If you do decide to go this route carefully mark where each gear / splined shaft meshes with its mates. They will have worn together over the years and you need to get them back in the same position or you will get more noise. get the manual too so you can follow the steps required. And above all dont force anything.

How far to withdraw - cant tell precisely but you will likely have to move the engine forward by sliding it up the bearers.

If you are nervous about DIY chat to your local friendly volvo dealer. Explain you want to do the job yourself but in return for a bit of hand holding / advice, you will buy the bits from him. Explain you may need rescuing. My experience is that people are very willing to help if you approach them nicely.
 
Hang on, hang on, everybody is jumping in to removing and stripping the box, need to check things out first to make sure it is the box, my druthers are, given the state of the shaft, that it was the cutlass bearing that was rumbling. If I am not mistaken your box is the one that they used to say use engine oil as lube and then started recommending 75/90 synthetic gear oil. Now I know from my box that the 75/90 gearbox oil goes v black v quickly and it stinks, a peculiar gearbox/hypoid oil stink, but there is nothing wrong with it. I would drain the oil, flush it and replace. If it does need bearing work it isnt a bad job, they are tiny boxes, just need to undo the prop shaft flanges, move the shaft back and then undo the gearbox and remove. I dont know the Moody but on my bene there is loadsof room to remove whilst in the water.
Stu
 
One question answered.
Yes it is safe to remove the Gearbox whilst the boat is in the water.
As skipper_stu said though--- hang on a mo!

I would sort the shaft/cutlass bearing out first before touching the gearbox.

If your gearbox uses engine oil it should be clean.
If it is and no leaks are obvious 9 times out of 10 the box is ok.
If the oil is a hypoid it should still stay clear but might'honk' a bit!


With couplings and cutlass bearings that resonate inside a boat.
Wouldn't suprise me (as others have said) thats where the problem lies.
 
When I took the gearbox from my Moody 31 MKII it was necessary to slide the shaft out by about 6-8 inches (at a guess) so this means disburbing the shaft seal. So it's not an ideal job to do in the water. I took mine out to check the spline wear that is well documented with these gearboxes/VP engines. See here
if you don't know all about it. Do you think it could be the start of the splines wearing to the point of loosing grip on the carrier ring attached to the flywheel? Has this job been done on your boat? ybw thread on it here

I think it's that or the cutless bearing. Can you run the engine and listen to the gearbox using a sounding stick?
 
[ QUOTE ]
If I am not mistaken your box is the one that they used to say use engine oil as lube and then started recommending 75/90 synthetic gear oil. Now I know from my box that the 75/90 gearbox oil goes v black v quickly and it stinks, a peculiar gearbox/hypoid oil stink, but there is nothing wrong with it. I would drain the oil, flush it and replace.

[/ QUOTE ]

Interesting - I wasnt aware of a spec change. The oil in my Volvo gearbox is clear and sweet smelling after 5 years without change, and my previous Yanmar box was the same for 10 years. But if you now use a hypoid oil (you can tell by the smell), then it may well be different and my immediate reaction above to black discoloured oil might be the wrong one. Best have a sniff, and maybe a chat with Volvo.

As for locating the rattle, go down below when someone else is driving and listen . Noise from the shaft bearing will come through the hull and be particularly noticeable by where the P bracket is glassed in. As for the gearbox you can always put a long screwdriver blade on the box and the handle to the bone in front of your ear - this will help you hear whats going on inside the box.
 
hermm, the vp recomendation is that gearbox oil should be changed every year! at least in th 20x0 series!!
Also I can assure you that they did change the recomendations, my 2030 had this box and was engine oil and my md22 has (i am pretty sure) this box and they recommend hypoid, i went in to this with vp engineers in scotland, it was an issue on the survey, and he was the one who said that they had changed it, the round robin that i get from keyparts also mentions that these b oxes have either engine OR hypoid oil.
Stu
 
[ QUOTE ]

How far to withdraw - cant tell precisely but you will likely have to move the engine forward by sliding it up the bearers.


[/ QUOTE ]
I think I might check this now before the boat is launched. It's easy enough to undo the 6 bolts. I assume there's no gasket between the engine and the box?

[ QUOTE ]

If you are nervous about DIY chat to your local friendly volvo dealer. Explain you want to do the job yourself but in return for a bit of hand holding / advice, you will buy the bits from him. Explain you may need rescuing. My experience is that people are very willing to help if you approach them nicely.

[/ QUOTE ]
I've used RK marine at Swanwick in the past. Obviously they charge VPs insane parts prices but they've always been very helpful.
 
[ QUOTE ]
If I am not mistaken your box is the one that they used to say use engine oil as lube and then started recommending 75/90 synthetic gear oil. Now I know from my box that the 75/90 gearbox oil goes v black v quickly and it stinks, a peculiar gearbox/hypoid oil stink, but there is nothing wrong with it.


[/ QUOTE ]
That's news to me. Oddly enough, 10 years ago when I first bought the boat, I asked the local VP dealer to sell me all the stuff for servicing the engine. Included in this was a bottle of gear oil. Yet the box says on it to use engine oil, as does the 'owner' manual. So I followed the manual. Still have the unused oil. I guess I should have asked....

[ QUOTE ]

I would drain the oil, flush it and replace. If it does need bearing work it isnt a bad job, they are tiny boxes, just need to undo the prop shaft flanges, move the shaft back and then undo the gearbox and remove. I dont know the Moody but on my bene there is loadsof room to remove whilst in the water.
Stu

[/ QUOTE ]
 
[ QUOTE ]
There is no gasket between the engine and gearbox.

Mine runs happily on engine oil per spec.

[/ QUOTE ]
Excellent.

So plan is
Replace the cutless bearing
Check the box can come out without removing the shaft. If so
Wait 'til the boat is in the water and hope rumble has gone!
Oh, and investigate using gear oil. (I'll phone RK marine - they've been helpful in the past)

Thanks all!
 
I suggest that your photo shows some shaft wear. My sterngear suffered rumbling noises for several seasons after fitting a new engine, despite replacing P-bracket, propeller, fitting Aquadrive, realigning engine, fitting alternative flexible mountings. Finally I replaced the shaft, which was worn to about the extent that yours appears to be. It is now perfectly quiet!
 
The photo is misleading. The lines on the shiny section are actually just incredibly hard scale. I started scraping it off last night with a bit of brass and it was hard work. Haven't finished yet. Then I'll test it with a vernier.

There is however wear where the old stern gland was. I need to measure up to see where this is in relation to the stern tube. Obviously this will affect which seal I buy!
 
Well, it may be difficult to make an assessment from a photo but it looks to me like there's a step at the upper right and left hand sides. I would definitely check with a micrometer or maybe vernier. The wear on mine was not excessive but replacing the shaft has brought a remarkable improvement.
 
You must log in or register to reply here.

Other threads that may be of interest

Y
Quick Aries 1000 anchor windless noisy
Replies
0
Views
101
yotter
Y
ianc1200
Sureseal shaft seal.
2
Replies
20
Views
507
ianc1200
ianc1200

Share this page

Top