Volvo D4-300 Transmission Problem

[rclarke246]

Transmission Problem on Volvo D4 -300

Hello,

I have a problem with my port side transmission on my 2016 Volvo D4 300 HP, 350 hours. Not sure of make/model of transmission.

Description:

1) Weeks ago, while cruising, experienced no thrust port engine forward or reverse. Discovered fairly major transmission fluid / leak around that transmission. Service company came and discovered a pin-hole leak in the cooling component on this transmission. Replaced this transmission cooling component on both engines.

2) After the replacement conducted sea trial of 30-50 minutes. All good. Seemed fixed.

3) Next outing, after about 1 1/4 hour running, variable rpm´s from 1,100-2,800, with the typical WOT of 3,500, experienced no thrust in either direction. Returned to port on starboard engine. Next day, with cooled system, had normal thrust.

4) Mechanics came for sea trial. Ran same route as 3 but couldn´t duplicate issue.

5) Next outing, 3-4 hours of normal operation. Fixed, I thought.

6) Outing Yesterday, typical 3-4 hour operation, all good except when docking I had no thrust again on port side. Changing helm station had no affect. No leak. Thrust returns when cool next day.

Normal (or even higher) RPM´s are there even when no thrust. Fluid level good, no burned fluid through all of this.

Any idea what is going on? Thank You

 

[twistedtree]

Assuming the transmission clutches are hydraulically operated, which would be indicated by having a cooling system, I think your next step is to get a pressure gauge on the transmission. Actually, two gauges. One for the system pressure, and one for the pressure at one of the clutches. Then next time it happens see what the pressures are. Also shoot the case temp to get an idea what the oil temp is.



No system pressure would indicate a pump problem, pressure relief valve problem, low oil but you have checked that, or some other internal problem.


System pressure but no clutch pressure would indicate pressure loss at the clutch itself, or a control valve problem. A control valve problem could be hydraulic, or it could be electric assuming solenoid control.


Both system and clutch pressure, but no clutch engagement would be an internal hydraulic or clutch problem.


I'd also look back to the pin hole leak and explore how it might be related. It most likely is related somehow. Perhaps, for example, something is causing an over pressure. That could have been the cause of the leak, but it's still over pressure which would lead to high oil temps and thinner oil that might fail to develop pressure at the clutch pack. That's just an example, of how all this might be related.

 

[rclarke246]

Twistedtree, Many thanks for this advice which I will share with the mechanic who's coming on Monday.