Hurth gearbox - loss of drive in ahead but fine is astern

[SwillyView]

A friend of mine has a 1993 29HP Perkins Perama with a Hurth HBW100 gearbox.

On taking her out one day at the end of last season we noticed a marked drop in drive while going ahead. Revs were fine but there was not enough power to make more than a knot or two. However there was masses of power when going astern.

We have carefully checked the gear shift cable and the lever it connects to on the gearbox and can see no problem or difference between forward and astern modes.

The boat is still in the water but we have checked the prop ( 3 blade fixed ) and can see no problem there.

At the beginning of last season we did top up the fluid in the gearbox which appeared to be very low, i.e. there was no level showing on the dip stick when we checked it. The manual called for "ATF Type A" but we could not find that so used Castrol ATF Dex II. The engine and gearbox worked perfectly all summer until " out of the blue" the loss of drive in forward gear occurred - it did not occur while underway / in use - so far as we can tell it was fine when she was moored up at the end of one trip but then short of power at the start of the next.

Does anybody have any suggestions as to what the problem might be?

A few years ago the boat was being moved by a yard in Scotland and one of their engineers felt that the clutch was slipping. The yard drained the transmission fluid, replaced it with diesel and then ran the engine for a brief period, which apparently solved the slippage problem. Is that maybe worth a try?

Thanks for your help.

 

[whiteheat]

I am experiencing exactly the same problem, but have loss of power going astern. If you found a solution, I would be grateful if you would please share it with me.
Thanks.

 

[Salty John]

Have you checked the fluid level carefully? The dip stick should not be screwed in to get the level.

 

[Deleted member 36384]

Some information from a resource that I use: -

Shifting Problems? First check and adjust your linkage. Linkage problems are very common on Hurth marine gears when mounted to auxiliary engines. If the problem is still there, see if there is a difference in the difficulty in engaging forward versus reverse. If it is significantly more difficult to engage the marine gear in forward as opposed to reverse, this indicates that the thrust washers are worn. The gear will require service or replacement.

http://www.foleyengines.com/resourc...rine-transmissions-ins-and-outs-basic-service

 

[peteK]

I have had the same problem with a HBW50,draining the oil and refilling with fresh oil seems to cure the problem.

 

[Caer Urfa]

A friend of mine has a 1993 29HP Perkins Perama with a Hurth HBW100 gearbox.

On taking her out one day at the end of last season we noticed a marked drop in drive while going ahead. Revs were fine but there was not enough power to make more than a knot or two. However there was masses of power when going astern.

We have carefully checked the gear shift cable and the lever it connects to on the gearbox and can see no problem or difference between forward and astern modes.

The boat is still in the water but we have checked the prop ( 3 blade fixed ) and can see no problem there.

At the beginning of last season we did top up the fluid in the gearbox which appeared to be very low, i.e. there was no level showing on the dip stick when we checked it. The manual called for "ATF Type A" but we could not find that so used Castrol ATF Dex II. The engine and gearbox worked perfectly all summer until " out of the blue" the loss of drive in forward gear occurred - it did not occur while underway / in use - so far as we can tell it was fine when she was moored up at the end of one trip but then short of power at the start of the next.

Does anybody have any suggestions as to what the problem might be?

A few years ago the boat was being moved by a yard in Scotland and one of their engineers felt that the clutch was slipping. The yard drained the transmission fluid, replaced it with diesel and then ran the engine for a brief period, which apparently solved the slippage problem. Is that maybe worth a try?

Thanks for your help.

I used to have a Hurth 100 and had similar problems years ago, wasted two months trying to sort it but in the end it was a new box, if your gearbox cable contol and gearbox arm are operating
then its the gearbox mate, I also assume you never ran the gearbox with no oil in, as that's fatal.

However as you may know (or may not know) Hurth was taken over by ZF transmissions, so I fitted their ZF10M gearbox which is an straight swop and almost exact the same gear ratio, (I now run on slightly less revs than before).

However IF you take the gearbox out I suggest you check the clutch or drive plate as its better known as if that is wearing change it at the same time otherwise you end up having to
strip everything out again sooner rather than later.

Also of Interest I use Castrol ATF oil Dex III for years and I follow ZF advise and that is I change the oil every 100 hrs engine running time or 12 months whichever comes first.

Others are correct you do not measure the oil dip stick screw IN, you just drop it in the top and check and do NOT overfill it.

Hope this might help

Mike