Volvo TAMD 74 with ZF gearbox ZF280A long delay engaging drive

[UK George]

I have a powerboat with 2 Volvo TAMD 74 EDC coupled to ZF Marine ZF280A gearboxes.

The issue I have is that the Starboard gearbox takes between 5 to 7 seconds to engage into forward or reverse gear after shifting the helm controls.

This issue started around 6 months ago when I notice it had a delay of a second or so longer than the port gearbox. This has steadily got worse and now being a 5 to 7 second delay.

Interestingly, It doesn’t have the delay dropping out of gear when the control is shifted back into neutral.

The delay time also tends to be shorter if either forward or reverse is selected once again within a second or so after returning to controls to neutral however, if left in neutral for more than 5 seconds, the delay returns to around 5 to 7 seconds again.

I have changed the gearbox oil with the correct grade and type according to the manual and cleaned the metal screen filter and magnet, this had a few tiny almost insignificant metal shards but was 95% clear, none of this has made any difference.

It has plenty of oil in the box and I checked level on the oil dipstick within 2 minutes of shutting engine down so the oil cooler hadn’t drained back giving a false “overfilled” reading (as per the ZF manual).

The gearbox has the electronic shift solenoids, the forward and reverse solenoids both make a “click” as soon as the helm controls are moved so there seems no delay with the signal from the helm controls.

Could these electronic control solenoids be sticking? Moving slowly?

Could the oil pump be failing to supply enough pressure?

(this boat is not fitted with gearbox oil pressure gauges)

Has anyone experienced this problem on here before and found the cause?

I would appreciate any suggestions as to where/what I should I be checking next?

Thank you in advance.

 

[scottie]

Check the oil pressure
Fitting even a temporary gauge on both boxes one at at time and comparing will give you an indication to start with
The fact that it’s one box and both gears does suggest that it’s oil related rather than solenoids

 

[Rikarde]

Have you switched the actuators between the engines - if the fault follow the actuator - it needs to be replaced..

 

[QBhoy]

Hi
I would try manually engaging gear at the gearbox it’s self. Bypassing the actuators etc. If it goes straight in, you know it’s not the box itself and related to the actuation.

 

[exec2k]

Could be gearbox inter cooler has a leak and releasing oil pressure needed to engage gearbox drive or actuators sticking / grabbing and slowly opening to the point of enough pressure engagement . Twin engines are there to exchange parts before purchase of replacements.

 

[volvopaul]

Could be gearbox inter cooler has a leak and releasing oil pressure needed to engage gearbox drive or actuators sticking / grabbing and slowly opening to the point of enough pressure engagement . Twin engines are there to exchange parts before purchase of replacements.

If the cooler was leaking you would see oil in the cooling water and the box would be empty in no time at all, so I’d dismiss that theory .

The ZF 280 wasn’t a great gearbox. Volvo specked it for the first D9 engines but sadly they totally miscalculated the very low down torque of the D9 matched to a heavy boat like the Broom 450 was a recipe for disaster , not too long after owners were being caught out with a box full of stripped teeth and heart stopping moments at sea on one engine praying the other would go the same way . The ZF 280 was right on it’s calculated limit for HP but no one calculated the torque Andy it’s torque that does the damage. The twin disc fitted to the same engin eisnt much better keeping MIT in business .

I’d say that the pressure is dropping and has caused the clutch plates to alter shape or buckle allowing too big a gap for the clutch piston to compress the plates. There are plugs on the valve block where you can tap in a gauge and measure the pack pressure under load this will tell you what’s happening .

 

[UK George]

Hi,

First of all, thank you everyone for your help and interest.

I have bought an oil pressure test kit from eBay last week (measures up to 500psi) and went to the boat to check these pressures.

From what I understand, there are 2 places to take a useful reading, one is on the back of the oil pump that should be a stable high reading, and the other is on the gear selector control unit located on the top the gearbox. there is a hex grub screw between the two control solenoids where a meter can be connected and then able to read the oil pressure to the clutches.

(If I am misunderstanding anything above, please feel free to correct me).

Unfortunately the hex grub screw in the control unit was so tight that as I was trying to carefully release this with gentle use of an impact driver, it just rounded the hex screw.

I guess I will have to remove the entire gear selector control unit now and attempt to somehow remove this grub screw.

I will at least first take a reading from the oil pump to see if that is generating the correct pressure (assuming that hex screw is more obliging).

Once again, thanks for the interest and suggestions, I do appreciate as I have limited knowledge with a gearbox leaving me slightly anxious going forward.



P.S. the solenoids on both Port & Starboard gearboxes make a "click" sound within a second of shifting the helm controls, so I am assuming that there is no additional delay programed into the helm throttle controls however, I will reread the manuals I have.

 

[jeni]

This is a long time ago did you ever fix the fault as we have the same fault on ours now

 

[Portofino]

They ought to have gearbox pressure gauges .Very useful to see .

 

[jeni]

I agree! Had a 3-7 second delay for ages. One engine will go into reverse but not forward! swapped solenoids it works but not under load then packs up again. Swapped acurators over to exclude them but now cannot clear fault codes! It appears to be a common fault.

 

[Elessar]

I have a powerboat with 2 Volvo TAMD 74 EDC coupled to ZF Marine ZF280A gearboxes.

The issue I have is that the Starboard gearbox takes between 5 to 7 seconds to engage into forward or reverse gear after shifting the helm controls.

This issue started around 6 months ago when I notice it had a delay of a second or so longer than the port gearbox. This has steadily got worse and now being a 5 to 7 second delay.

Interestingly, It doesn’t have the delay dropping out of gear when the control is shifted back into neutral.

The delay time also tends to be shorter if either forward or reverse is selected once again within a second or so after returning to controls to neutral however, if left in neutral for more than 5 seconds, the delay returns to around 5 to 7 seconds again.

I have changed the gearbox oil with the correct grade and type according to the manual and cleaned the metal screen filter and magnet, this had a few tiny almost insignificant metal shards but was 95% clear, none of this has made any difference.

It has plenty of oil in the box and I checked level on the oil dipstick within 2 minutes of shutting engine down so the oil cooler hadn’t drained back giving a false “overfilled” reading (as per the ZF manual).

The gearbox has the electronic shift solenoids, the forward and reverse solenoids both make a “click” as soon as the helm controls are moved so there seems no delay with the signal from the helm controls.

Could these electronic control solenoids be sticking? Moving slowly?

Could the oil pump be failing to supply enough pressure?

(this boat is not fitted with gearbox oil pressure gauges)

Has anyone experienced this problem on here before and found the cause?

I would appreciate any suggestions as to where/what I should I be checking next?

Thank you in advance.

If it’s the pump it will be equally slow going into forward and reverse.

I had this issue and it was the control box on the top of the gearbox.

I had a spare from a broken gearbox and that cured the problem immediately.

You can test if the problem is electronic by taking the actuator off and putting it into gear manually. Google that if you don’t have the manual.

That faulty control box is now being diagnosed by Colin Ryan to see what the cause was as I have a friend with the same gearbox and the same problem.

Hopefully once my friends boat is sorted I will have a spare, working control box. I also have two spare and brand new actuators.

You could borrow these for diagnosis.

Hopefully it is this external box because it is a 5 minute job to swap them.

On an old box I had an oil way inside the box break up which stopped the oil pressure getting to the clutch. The gearboxes are rebuildable and parts are available but with long lead times and so I put a new box in to avoid missing boating time (which is why I have spare bits!)

[just seen this is an old post so that was a waste of typing time!!]

 

[volvopaul]

If it’s the pump it will be equally slow going into forward and reverse.

I had this issue and it was the control box on the top of the gearbox.

I had a spare from a broken gearbox and that cured the problem immediately.

You can test if the problem is electronic by taking the actuator off and putting it into gear manually. Google that if you don’t have the manual.

That faulty control box is now being diagnosed by Colin Ryan to see what the cause was as I have a friend with the same gearbox and the same problem.

Hopefully once my friends boat is sorted I will have a spare, working control box. I also have two spare and brand new actuators.

You could borrow these for diagnosis.

Hopefully it is this external box because it is a 5 minute job to swap them.

On an old box I had an oil way inside the box break up which stopped the oil pressure getting to the clutch. The gearboxes are rebuildable and parts are available but with long lead times and so I put a new box in to avoid missing boating time (which is why I have spare bits!)

[just seen this is an old post so that was a waste of typing time!!]

Ha ha , great reply though

 

[andy59]

Yep , thanks Elessar for the informative reply, still valid no matter when the thread started

 

[Captainslt]

I have a late ZF 280-a gearbox attached to TAM 75p engine.
I had the exact same problems with a five second delay on the starboard forward gear. When I remove the solenoid, there is a fine wire gauze which was clogged with metal fragments. On removing the fragments, cleaning the solenoid and reassembling the system works well. Whilst this solves immediate problem, the fundamental problem was where the metal filings were coming from? in my case, I suspect either a bearing, or clutch Is failing……….

 

[volvopaul]

I have a late ZF 280-a gearbox attached to TAM 75p engine.
I had the exact same problems with a five second delay on the starboard forward gear. When I remove the solenoid, there is a fine wire gauze which was clogged with metal fragments. On removing the fragments, cleaning the solenoid and reassembling the system works well. Whilst this solves immediate problem, the fundamental problem was where the metal filings were coming from? in my case, I suspect either a bearing, or clutch Is failing……….

Clutch plates failing unfortunately

 

[hinch]

I have a similar issue on tamd74 engines with zf gear boxes both engines 3-4 seconds before engaging drive in either forward and reverse. what confuses me is both engines are identical in behaviour so its not like i can say its solenoids or oil pressure on one side over the other. not sure what the issue is at this time but i like the thought maybe its the gause getting clogged so maybe I'll just pop the solenoids out first and check see if that helps.