NEW PRM 750D gear overheating and MFG not responding

[Flyguy1967]

Cummins 6BTA Repower complete and went for sea trial.

Arrived at the boat and mechanic on the phone with supplier trying to troubleshoot why starboard gear was 125F at the dock (port was reading 80F) - both gears are new.

We were told by the supplier to go for the sea trial and if the gear reached 200F, shut it down and head back.

Engines ran great and cool (all coolers taken to radiator shop, boiled and rodded) but starboard gear got too hot (200F) and got warmer at idle on way back so shut it down until we needed to dock.

Pulled gear and delivered to suppler for troubleshooting.

Looked inside case and all is good. Pressure tested, good. Bench tested, got hot but PRM said in-spec. Mechanic, supplier and Cummins rep (who happed to be at the supplier's shop), all pow-wowed around the gear, staring at the gear, and came up with some ideas to try to keep it running cool because PRM, at this point, will not replace.

Ideas include: increase RPM on engine to increase flow, increase diameter of cooling hose, get larger cooler. What is not making sense is the port gear, with same size hose and cooler, runs cool as a cucumber.

What are my rights? What can I demand? We are picking up the gear tomorrow to try the "fixes" but then what if that does not work?

Any suggestions as to possible issues with the gear that have not been thought of or how best to deal with this situation would be most helpful!

 

[STB]

Were there any similar concerns before rebuild?
Are there any tight angles with the fluid hose?
Were the hoses and fittings replaced?
Do the engines run at the same temp?
Are the two installations exactly symmetric?

I'd check the oil for loss or dilution, just to be safe.

I'd put an IR thermometer on the coolers and see how their external temp compares on each side. It might give you a small hint.

I'd check the raw water intake thru hull, seacock, impeller, and discharge seacock(if present) and thru hull, as it is easy to do.

I'd pull that cooler and double check that you didn't get unlucky and it clogged with some debris from installation, etc.

Then I'd disconnect the hoses at both ends and blow them out and run a wire through them or stretch them tight and look for light (if either is possible). I'd be concerned about debris or internal delamination.

Just sideas. was.

 

[FF]

New castings can sometimes be less than perfect. As suggested

disconnect the coolant intake and discharge for both trannys.

Then use a hose to see the water flow on the "good" one and shift over to see the hot one. A bit of water in the bilge as you switch the running hose over is no big deal.

 

[twistedtree]

I would press PRM for a swap of the entire unit while it is out of the boat. If it got hot on the bench then something is wrong. Maybe it wasn't out of spec on the bench, but it clearly was once in operation. Your supplier should be on your side with this since they are presumably eating the extra labor for the remove and replace of the gear box.



Remind them what the front page of their web site says:


"All gearboxes are supplied with a no quibble two year warranty which demonstrates the quality of our products."


So why are they quibbling over this?