Bukh DV 36 Gearbox Failure

[KenMcCulloch]

Our gearbox stopped doing its job today. The linkages work, the lever on top of the box moves in the prescribed way but no drive in either forward or reverse. With the engine stopped the propshaft can be turned by hand, no untoward sounds associated with that, the oil level and grade of oil is correct.

Anyone with experience of similar failures on a similar gearbox, comments welcome.

 

[NorthUp]

First guess would be the driveplate, between flywheel and gearbox input shaft.

 

[brianhumber]

My 25 year old PRM Newage Delta box did just that in October. On removal it was the splines in the drive plate which had fretted away. On tick over did not get any abnormal noise but when put ahead/astern metallic noise came from splines on the shaft which were grinding past the worn slots in the drive plate under load.

Similar to your failure?

Apparently the early Delta were prone to this and new boxes have a much large spline on the primary pinion.

Got the box off and found drive plate as described. Although new primary pinion and plate were still available, cost of new pinion/driveplate/bearings and seals was 2/3rds cost of new box and repairing the old would still give me a repaired 25 year old box, so I bought brand new drop in box. Saved me the agro of repairing as well although the rest of the box internals were still like new, no wear on the clutches at all. Offered the old box to the supplier but he showed me lots of similar exchanged boxes in his workshop all with same fault.

Got the box in but alinement has been another saga. Still finding new elements of Sadler **** build quality even after c20 years of ownership. Joys of owning a old racehorse I suppose.


Best of luck

Brian

 

[Paragon]

Hi Ken

I had similar with a DV20 with a BW7 gearbox, turned out the gearbox was ok but the coupling at the end of it had corroded and was basically spinning on the output shaft. I ended up changing it for the later gearbox, which on the mooring was interesting, but all ended OK.

Regret no other suggestions other than already suggested regarding the splines.

Good luck.

 

[SimonJ]

The best advice on BUKH issues always comes (willingly and free) from the BUKH guys in Poole. (01202 668840 - I would not go anywhere in my boat without this number!!)

But, I would look at the coupling first.