Gearbox out

[fushion julz]

So following the failure of the gearbox last week, I decided to let Lancing Marine investigate and repair...

I removed the gearbox from Hermes yesterday...It was a bit of a struggle, tbh...Firstly, without any clear info on how to proceed, I removed the 4 nuts on the coupling to the shaft and moved it back as far as it would go (boat is still afloat)...which amounts to about 3 inches.

I then removed the pipes and coolers in the way of the mounting bolts and removed the drive plate from the back of the engine. At this point I was hoping to get the 'box onto the deck, but the drive plate was not allowing enough movement/swing on the 'box to allow it to be lifted...so I had to remove the drive plate in the bilge...probably just as well as the stud length on the mounts wouldn't have allowed the 'box to move back enough to give clearance.

It was a bit of a struggle to get the box onto the deck as it is *loody heavy! Especially it the awkward angle ...

Still, it is now out and at Lancing Marine awaiting a slot (hopefully end of this week or beginning next) to get it looked at.

The front seal was loose and out of it's place on the input shaft, so that is definitely the cause of the leaking fluid...But why the seal failed and what other damage is, as yet, unknown.

[Firefly]

Should have done it yourself. Very easy and cheaper and a pleasure to learn something.
Perhaps time was a factor.
To remove from the bilge needs a beam across the coamings and a small block and tackle.
Horrible heavy thing.
David.

[fushion julz]

Yeah, time (as in time to do the repair, sourcing of parts) and knowledge is the issue...

I'm reasonably sure something caused the seal issue, but what is the question.

Given I wouldn't know a good pump from bad, nor a good clutch pack from bad, with the cost of the parts and availability plus the time issues, I thought having someone like Lancing Marine do the job (that has a warranty at the end) was preferable.

I didn't have either a long enough 4x2 plank to go across the coamings (plus the coamings slope at that point) or a block and tackle, so the plank was across the engine cover and I was using ratchet straps to lift it...but the lack of space between the engine and the shaft was an issue and the turbocharger was also in the way (and I didn't fancy removing it)...I managed, but suspect getting it back in may require assistance!

[Richard]

Fushion,
Do you mean that you removed the "Adaptor plate" ,not the driveplate which is bolted to the flywheel?
If that was the case,I'm sure if you re bolt the adaptor plate,to the flywheel housing, then remove the 6,
1/2 inch UNF studs from that plate.

Then when you get the transmission back you should have a bit more space
slide the splined input shaft into the drive plate and put a wooden block quickly between the propshaft
flange and trans flange,especially if your rolling around on a mooring or pontoon,then fit two nuts to a stud,
and wind them in one at time, I've done this on a Spear and a 31 ft Huntsman many moons ago.
The 31 was Alex Moulton's (707) in Guernsey, that had Sabres in and was easier because John Freeman,
had the sense to use bolts instead of studs.
Good Luck!

[fushion julz]

Hi Richard...thanks for the hints...

Yeah, I meant the adaptor plate...Basically the marine equivalent of a car/truck bellhousing as, having done many vehicles with wheels, it is *always* the case to remove the gearbox with the bellhousing and then seperate them (if required) on the bench...

Some of the studs came out with the nuts in any case and I will be seperating them, cleaning them up and loctiting the studs back in on reassembly.

If I fix the adaptor plate back on to the engine (having cleaned up all the transmission fluid, first...there is plenty on the driveplate and in the rear engine casting), there may be issues in getting the gearbox in and onto the splines in the crankshaft as the space is so limited!
But I willcertainly consider this as you have obviously had experience doing the same job. Fortunately, although the boat is on the water, the marina is locked and is always calm with only the wind affecting the motion.

(PS: name is Julz...Fushion is an old DJ name relating to my sound system!)

[Richard]

Juiz,
You'll be fine,at least your borg warner box is only about 30-35 kilos empty,I mentioned the block because your engines
mounted at an angle of of approx 15 degrees so watch out for your fingers.
Another tip only remove the exhaust if absolutely necessary,& if you do tie the end up as high as possible or better still
blank it off with heavy duty polythene with the clips nice & tight ,the outlet through hull is usually almost on the
waterline , many a boats been left on the river a few hours & then as disappeared, glug glug!.
Also there may be a drain plug in the underside of the flywheel housing 1/2 inch square I think.

[fushion julz]

So now have a preliminary verdict on the 'box from Lancing Marine...

It would appear that both forward and reverse clutch packs are required along with a seal and gasket kit...Although the front seal is undamaged it is prudent to replace it (cost is only £6 ish)...

The real issue, however,(and something that may interest other Velvet Drive users) is that the pump appears to be working OK, but is an old style one...The later pumps have a lip on the front to prevent the front seal being ejected from it's seat (which is what has happened in my case)...Seal loss leads to rapid fluid loss and damage to the clutch packs.

The new style pump alone is approx £250 ...together with the clutch packs (about £135 each) and seals/gaskets (approx £60) added to the labour charge is going to result in something close to £800-900 cost...Ouch! all due to an unknown deficiency in the pump design on early models!
Had I known this in advance, I may well have either insisted it was done prior to purchase or done it immediately after I got her!

[fushion julz]

And the final (ish) verdict:

These parts need replacing:
Forward clutch pack @ £135
Seal and gasket kit @ £43
2 x reverse plates @ £33 ea
Input shaft speedy sleeve @ £39
Neutral switch @ £26
2 x Bushes @ £46 ea
Output flange nut @ £15
Output shaft Speedy Sleeve @ £46

plus about £400 in labour
all plus VAT

Not including a pump that may still be required...won't know until a test after rebuild...

Means a bill just shy of £1100....or nearly £1400 with the pump!

Which is about the same price I can get a full recon unit for elsewhere!

[fushion julz]

So yesterday, with the assistance of a friend (without whom, I suspect the whole operation would have failed) the replacement gearbox was fitted into Hermes.

There are still the gearbox cooler lines to connect, as the supplied (with the new gearbox) unions were of a different size to the ones on the old 'box...I will be reusing the old ones for now.

Hints gleaned from doing the job...
1. The gearbox is *very* heavy...especially when working in a restricted space below knee level!
2. It is extremely front-heavy...which makes locating on the driveplate splines at an inclined backwards angle exceptionally tough.
3. The shaft coupling had to be loosened and moved as far back as possible to allow enough clearance to get the box in at all.

I have investigated buying the parts to renovate the old box in time...A complete clutch plate, seal and gasket set along with a pump is available at £245 (£150 without the pump) which is significantly less than the prices quoted by Lancing Marine.
However, the input shaft is very badly pitted and the likely cause of the front seal popping out in the first place.

Allegedly there is a sleeve (called a speedy sleeve) to cure this, but I can't see how as it wouldn't be thin enough to allow the (tight fitting) seal to slip over it...
So not sure, yet, if it is going to be viable to fix. A visit to my local engineering shop may establish if the shaft can be saved.

[Rima V]

Have a look at simply bearings, the use of a thin stainless sleeve on marked shafts is commonplace
Al

[fushion julz]

Today I went out for a quick trip to test the gearbox and confirm all is working as expected....

Just need to rebuild the old one now...

[Richard]

Julz.
Good news your'e back together & running again,
SKF sell Speedy Sleeves,I've fitted them on Detroit Diesels
crankshafts & they work very well.If you do fit one it's
pretty simple,polish any high spots or corrosion on the
shaft with emery cloth,if your pitting is quite deep &
your worried about oil leakage between the shaft diameter
& the bore of the sleeve , lightly coat the shaft with some
Loctite bearing retainer warm up the sleeve in hot oil!
obviously not too hot , the sleeve will grow a few "thous's
& slide over the shaft to the worn/pitted section hold it
there till it shrinks.
We didn't like bashing them too much, they look very Flimsy!
But it does cut out machining costs

Richie.

[tjsb]

Just enjoying looking over old posts. I think pitting on the input shaft is unlikely to generate the pressure to push out the front seal. Having had this problem a few times, the first was a sticky shift valve which led to pressure relief valve problems. If the pressure relief valve doesn't, then the seal which is only held in by sealant will give. I also ended up clearing out all passage, coolers and hoses on mine, and even small objects can cause increases in pressure. I have made up a special tool to be able to test the pressure (see separate post on BW72c test) in case anyone needs to check.