repairing 30hpDMHL 2000 yammie gearbox

[CreelReaper]

Hey guys,
I would really appreciate your help on this one. The gearbox started making some strange noises over Easter when my son went down the pin. The following weekend I checked to find no oil in the box so refilled as normal. Started the motor and engaged gears a number of times. Couldn't hear any probs. Although there was a slight oil leak coming out of the centre hub area (prop shaft).
Took the boat for a run and sure enough as soon as there was any weight on ther prop a 'clicking noise' could be heard. (Forward and reverse). After 5 minutes or so of running the clicking noise increased and the engine stalled.It started easily enough and even though I could engage gears there didn't seem to be much drive power. Now the last time I had it serviced the guy said the dog clutch showed some wear. This I am assuming is the cause of the problem. I want to do the repairs myself to see just what condition the gearbox is really in.
Now in dismantling the gearbox I have been told by a number of guys that you need a special tool to undo the bearing housing retaining nut and claw washer and then i was chatting to a mechanic that says you don't, you just need a lever or such to remove them.
Two questions if I may....
1) If it isn't the dog clutch that is worn what else could I check for
2) Is there anything I need to be concerned with in regard to dismantling the gearbhox. Do I really need this special tool??

I appreciate all help and thanks heaps in advance.

Shane

[Spaniard_King]

Watta,

gearboxes are really a specialty area,

IMO you most likely have suffered some pinion gear damage which inturn will damage both forward and reverse gears:'(

Most gearboxes thet require the fwd gear or pinion gear replacing will need shimming this in it's own can be difficult to acheive even for the experienced mechanic. It is very important to have the rightmesh between the fwd gear , pinion and reverse gear or damage will be sooner rather than later.

To complete the rebuild the gear box will need to be presure tested to ensure all the seals are working correctly.. Do you have the means to do this?

If any of this seems difficult... it may be best you have a specialist do it:-/

[CreelReaper]

Thanks Garry.....Yeah the pressure test is not a problem. My son has a couple of contacts and they did a rebuild around September last year for a great price. Whilst he was willing to inform me on the dog clutch wear I couldn't get too much more info. I know that the seals and bearings were replaced but thats all. At least if I strip it down myself I'll feel a little more comfortable in knowing what problems there might be. I know that we had done 3 or 4 oil changes before the rebuild and there has been no sign of filings etc in the oil. When i checked it this last time however i did find some black coloured ( I think rubber or similar) in what little bit of oil came out of it.

Shane

Shane

[CreelReaper]

Hey guys,
Finally got a chance to have a better look at the lower unit. I have dismantled part of it and can't seem to work out how to remove the prop shaft bearing housing. Does the whole shaft come out as 1 piece using a bearing puller or do you have to remove the bearing housing first. I appreciatye and many thanks for your advice.
One thing also I noted is that the drive shaft is extremely hard to turn even in neutral. Does this sound right??

Shane

[ausandy]

watta, yry mark at yamawreck in melb for any s/hand bits you might need..... mob 0400791155

[FNQCairns]

Can you see the two bolt holes in the bits radiating from the carrier assemably? those are where the puller attatches too, I assume you have the big sacrificial ring nut and tab washer removed.

You are in the poop like Gary says, can you lap one of these? needs someone with at least a little experience and the care to bother doing a good job for a long lasting reliable result.

If you can wait a while this place will sell you the bits for possibly 50% less than here and they have good schematics as well, reliable bunch have used them a few times now.

http://www.boats.net/parts/search.html

cheers fnq

[CreelReaper]

Hey guys,
Thanks heaps for the tips. Yeah, i have access to the workshop boys at work. They do a good job. I can always go back to the marine shop if I have to. I just enjoy tinkering and learning new things as i go. Never done a gearbox before so that is why I asked some questions. Once again many thanks. truly appreciated

Shane