Transmission Temps

Took the boat out to view the Eclipse on the Tennessee River. Awesome, no really awesome.
Drove an hour upriver, anchored couple of hours and drove home. About 50 minutes into the return trip the port transmission oil gauge climbed to 220 degrees while stbd remained at 150.

Dropping RPM's to enter marina, the temperature dropped along with the RPM'S to 140 port and 120 stbd.

Went into the engine room to shoot with the infrared gun, which is my practice every hour anyway, and at the transmission dip sticks on both the temperatures were 140.

Prior to trip, oil clean and honey colored. Port showed full prior to starting and Stbd was down between the low mark and end of dip stick. What kind of oil does it take? Also, no evidence of leaks out the breather, at the filter, or tracing the cooling lines.

No misbehaving shifting. Getting into my slip is a lot of shifting work cause the aisle is 75' for the 56' boat. No slipping and no delay moving into gear.

Also I really think the cooling system needs to be flushed. Brown crude floating on top of the coolant. Thin crust. Any body know of someone in Chattanooga greater area besides D D who could do the work? I think it is beyond my rookie expertise.

Thanks in advance as always.
mark

Look up "Diesel Don". He's good, but not cheap. Also you might shoot the transmissions while underway, They may be OK and the gage is wrong. I use 40 weight in my M-15's.

Bobk

I use same oil In my ZF's as I do my 12v71's, straight 40w

I know on our 12-71 trannys have a max operating temp of 210 degrees with 40W oil. I agree take mechanical temp reading to verify the findings. You may need to take a look at your cooler and see if its functioning properly if that is an accurate reading.

This boat has 8v92ti and I think allisons. Anybody know normal operating temps at 1000 rpm's? And what is the right oil weight? Thanks

If you have Allisons then they should run in the 150 range and oil should be straight 40wt or 30wt if you run in colder weather. Oil levels shouldn't fluctuate so you may have a leak. Make sure you are checking the oil in the same conditions. The level will be different when cold and after they are run. Temp could be a dirty or bad oil cooler. I'd get the coolant flushed ASAP. Crud in your coolant can ruin your engines and be a sign or other problems. Might want to have the coolant analyzed for contaminants. Only use Detroit coolant. If coolant types have been mixed you can get a nasty brown sludge. I'd do a proper engine flush and start with fresh Detroit Powercool.

That s big temp differnce.

Allisons take straight 40 like the engines but must be checked warmed up and which engine at idle. If you read the original marks on the dipstick cold and engine off, the level will be lower than it should be. What you can do is check it warm and running than after it cools mark the dipsticks for a cold reading. If I remember right, it will be about an inch above the full mark

What is odd is that despite being low you had no delay in forward.

How about engine temp, where they not th same? And water flow out the exhaust, same ?

If engines temp and flow are the same then I'd suspect and internal problem is make the gear run hot, not a cooling flow issue

Thanks for the insight, I'll do the tests when up there next week. This weekend going to NY for wedding.

If cold would be above the full on the dip stick than the port engine would be about right.
Since the stbd was below low when cold, it perhaps is leaking it somewhere.

I did notice after shutdown at the dock a slight oil sheen on the remaining water coming out of the exhaust on the stbd but not on the port. Would a leak in the oil cooler be a potential cause? Could I top off the transmission and watch the level, if it continued to dissappear than perhaps the oil cooler needs to be replaced.

mark