2005 390 W 5.9LC QSB Gearbox Running Hot

[suss1173]

I am running our boat up the coast and experienced a temperature alarm on the Port ZF80 gearbox. We verified the alarm with an IR gun and the box is running at 270 when running @ 80 % load.

After pulling into port we verified a few things.
Water to hyd Oil Heat exchanger is clear and operating properly.
Looking at the hyd system pressure it seems to be running lower than Starboard motor.
Port 60psi idle in gear
Star 110psi idle in gear

Making the assumption the sol were not fully shifting the spool we swapped them with the good motor and no change.

We are down to either the hydraulic pump or ZF gearbox.

Would the hydraulic pump head be the only reason we would have lower pressure? Or is there something mechanically in the gearbox that would also cause this symptom. Our theory is the clutches are slipping since we are below full lock pressure. However the oil looked good and did not smell burnt after running for a while before realizing it wasn't a faulty temp sensor.

Any advise would be appreciated.

 

[Strecker25]

Can’t help with your question but I’ve read that these guys are great and will assist over the phone. Might be worth a try

http://www.marinegears.com/contact.php

 

[ttmott]

High temp is from two things - lack of cooling water to the Hx and/or slipping clutches. And 270 degrees is way too high.
I would say first to check the ZF service documentation and find out what the hydraulic acceptable pressure range is; however, it looks very low to me.
Low pressure could be attributed to a couple of things:

• Plugged filter element; if the filter is becoming plugged with clutch material then it is a self-eating watermelon and the gear needs to be rebuilt/replaced.
• Hydraulic pressure regulator has debris hanging it open or the spring has failed.
• There is a suction pressure air leak and the hydraulic pump can't pressurize consequently the clutch packs cannot engage fully. The typical culprit is the filter access cover.
• Incorrect hydraulic fluid was put in it.

 

[johnq29]

I am running our boat up the coast and experienced a temperature alarm on the Port ZF80 gearbox. We verified the alarm with an IR gun and the box is running at 270 when running @ 80 % load.

After pulling into port we verified a few things.
Water to hyd Oil Heat exchanger is clear and operating properly.
Looking at the hyd system pressure it seems to be running lower than Starboard motor.
Port 60psi idle in gear
Star 110psi idle in gear

Making the assumption the sol were not fully shifting the spool we swapped them with the good motor and no change.

We are down to either the hydraulic pump or ZF gearbox.

Would the hydraulic pump head be the only reason we would have lower pressure? Or is there something mechanically in the gearbox that would also cause this symptom. Our theory is the clutches are slipping since we are below full lock pressure. However the oil looked good and did not smell burnt after running for a while before realizing it wasn't a faulty temp sensor.

Any advise would be appreciated.

I am running our boat up the coast and experienced a temperature alarm on the Port ZF80 gearbox. We verified the alarm with an IR gun and the box is running at 270 when running @ 80 % load.

After pulling into port we verified a few things.
Water to hyd Oil Heat exchanger is clear and operating properly.
Looking at the hyd system pressure it seems to be running lower than Starboard motor.
Port 60psi idle in gear
Star 110psi idle in gear

Making the assumption the sol were not fully shifting the spool we swapped them with the good motor and no change.

We are down to either the hydraulic pump or ZF gearbox.

Would the hydraulic pump head be the only reason we would have lower pressure? Or is there something mechanically in the gearbox that would also cause this symptom. Our theory is the clutches are slipping since we are below full lock pressure. However the oil looked good and did not smell burnt after running for a while before realizing it wasn't a faulty temp sensor.

Any advise would be appreciated.

Can’t help with your question but I’ve read that these guys are great and will assist over the phone. Might be worth a try

http://www.marinegears.com/contact.php

 

[johnq29]

I am running our boat up the coast and experienced a temperature alarm on the Port ZF80 gearbox. We verified the alarm with an IR gun and the box is running at 270 when running @ 80 % load.

After pulling into port we verified a few things.
Water to hyd Oil Heat exchanger is clear and operating properly.
Looking at the hyd system pressure it seems to be running lower than Starboard motor.
Port 60psi idle in gear
Star 110psi idle in gear

Making the assumption the sol were not fully shifting the spool we swapped them with the good motor and no change.

We are down to either the hydraulic pump or ZF gearbox.

Would the hydraulic pump head be the only reason we would have lower pressure? Or is there something mechanically in the gearbox that would also cause this symptom. Our theory is the clutches are slipping since we are below full lock pressure. However the oil looked good and did not smell burnt after running for a while before realizing it wasn't a faulty temp sensor.

Any advise would be appreciated.

Good Evening,
I just had an identical experience with my 05 390.
What was diagnosis and fix for your high temp alarm and low gear pressure?
I’m hesitant to call Cummins until I’m positive the repair is above my means!
Thanks in advance for your time!

 

[suss1173]

Good Evening,
I just had an identical experience with my 05 390.
What was diagnosis and fix for your high temp alarm and low gear pressure?
I’m hesitant to call Cummins until I’m positive the repair is above my means!
Thanks in advance for your time!

If you are having transmission issues, you do NOT need a Cummins tec, you need a transmission tech. Ultimately my issues was a bad transmission. The clutch's were shot. Best guess as to the cause of this, was that the prior owner money shifted the boat (shifted from forward to reverse at higher RMP and load). But I have no way of verifying exactly what took place.

My low pressure issues was due to very fine particles (from the warn clutch's) getting caught in the pump and this would take out the pump. The elevated temps was due to the clutch's being worn out. Do you currently have low pressure? (you should have 350psi under load) or just elevated temps? If it is just a temp issue, I would first make sure you don't have a plugged cooler (this could be something for a Cummins tech or diesel mechanic). If you want to talk, PM my your info and we can talk it through.

 

[johnq29]

If you are having transmission issues, you do NOT need a Cummins tec, you need a transmission tech. Ultimately my issues was a bad transmission. The clutch's were shot. Best guess as to the cause of this, was that the prior owner money shifted the boat (shifted from forward to reverse at higher RMP and load). But I have no way of verifying exactly what took place.

My low pressure issues was due to very fine particles (from the warn clutch's) getting caught in the pump and this would take out the pump. The elevated temps was due to the clutch's being worn out. Do you currently have low pressure? (you should have 350psi under load) or just elevated temps? If it is just a temp issue, I would first make sure you don't have a plugged cooler (this could be something for a Cummins tech or diesel mechanic). If you want to talk, PM my your info and we can talk it through.

Good Evening Again,

THANK YOU for taking the time to reply!
My starboard gearbox was running 350 PSI with a temp of 111 degrees.
My port gearbox was running 114 PSI with a temp of 199 degrees, which triggered the alarm.
This was an odd occurrence as its run perfectly for the 6 years I've owned it.
Heres where I'm wondering what went wrong:
I had my 1000 hour service performed by Cummins 2 weeks ago and the fluid in both transmissions was changed.
The alarm tripped on my first extended cruise afterwards and I'm wondering if changing the fluid sealed my fate.
This morning I pulled the filter and found particulate and a relatively large piece of clutch plate, which indicates the unit is toast. I spent the day trying to locate a new ZF 85 IV with a 1.6 gear ratio to no avail.
Any info on who you used for your parts and repair would be much appreciated!
Thanks again for your reply! This forum has been a HUGE help over the years!
I can be reached daily at (616) 299-1007 and my name is John.

 

[suss1173]

Good Evening Again,

THANK YOU for taking the time to reply!
My starboard gearbox was running 350 PSI with a temp of 111 degrees.
My port gearbox was running 114 PSI with a temp of 199 degrees, which triggered the alarm.
This was an odd occurrence as its run perfectly for the 6 years I've owned it.
Heres where I'm wondering what went wrong:
I had my 1000 hour service performed by Cummins 2 weeks ago and the fluid in both transmissions was changed.
The alarm tripped on my first extended cruise afterwards and I'm wondering if changing the fluid sealed my fate.
This morning I pulled the filter and found particulate and a relatively large piece of clutch plate, which indicates the unit is toast. I spent the day trying to locate a new ZF 85 IV with a 1.6 gear ratio to no avail.
Any info on who you used for your parts and repair would be much appreciated!
Thanks again for your reply! This forum has been a HUGE help over the years!
I can be reached daily at (616) 299-1007 and my name is John.

 

[suss1173]

Hi, John. I will try to reach out to you tomorrow. However, I would agree, that based on the chunk of clutch in the filter, that it is time for a rebuild. My guess is that the particles took out your pump and that is the reason for low pressure. But, who knows what took the clutch out???

I would reach out to Rick at East Coast Marine Transmissions in NJ (732) 991- 0694. He is a wealth of knowledge, honest, and fair. He can also ship a rebuilt unit or possibly find you a new one. Also Bay Diesel in VA is a great source for any Cummins or ZF parts, including the pump that you need. IIRC it was about $1,400 for the pump last summer.

Sorry you are dealing with this and I will help anyway that I can.
Regards,

Michael S.