Perkins T6-3544 Transmission Oil Question

I have two of the subject engines and associated transmissions.

I found the starboard transmission oil level to be at the bottom of the dip stick. The oil was clear and about the color and consistency of new motor oil.

I found the port transmission oil level to be at the full marker on the dip stick, but the oil was a light tan creamy color. The oil felt a little thicker than the oil in the starboard engine but had a very rich oily feel.

I would appreciate any wisdom about my findings.

Thanks for your help.

Likely water in the transmission oil. A failed cooler is the normal suspect. Do not run the boat until problem solved. Many consider the transmission cooler a throw away item before they start leaking. Change the oil nd filter asap, remove the cooler and hook the hoses together and run the engine at the dock in forward and reverse. Repeat oil and filter change and run briefly again in gear.

Hopefully no strange sounds are heard. Replace both coolers and use the “good” one as a spare. Sample oil from both sides once you’ve flushed water out. Good luck.

What sunshades said, just noting that you may not have q meaningful transmission oil filter. Many are just a screen.

MrCool.us has those coolers.Russ and Brandon there have sold me all of mine for 2 boats.

Will my engine oil coolers go next?

The engine has a triple heat exchanger. The transmission oil cooler section in the middle had already been replaced by a 2"x12" copper cooler. It was installed before the sea water pump. This is what is leaking sea water into the transmission oil on the port engine.

The engine oil cooler is at the start of the triple cooler, connected to a hose from the sea water pump. The turbocharger after cooler is at the end of the triple cooler, before the sea water goes to the manicooler.

What is your experience with the engine oil cooler and the after cooler failing? And, are there preventive measures I can take to extend there lives? What about the manicooler?

I can buy a dual cooler to replace my copper transmission oil cooler. It would cool both the transmission and engine oil.

The triple cooler replacement costs $4300. The dual cooler costs $517. The copper transmission cooler costs $147.

Thanks for your help.

Transmission Oil Coolers

Lenco also has the coolers.

Thanks

It is really hard to say without seeing them, and maybe in them, at least for me. Condition is everything.

The best thing to do is to periodically (every few years) take them off, clean them as needed, inspect them, and maybe have a shop pressure test them. For the big coolers, that is rarely done, at least by most, but more commonly and frequently done for the smaller ones. And, in between, keep an eye on things and maintain as needed.

But, this is one of those things where personal philosophy and type of use matters a lot. The balance between PM, boating, and the rest of life tends to be a very individualized one.

I pumped out the transmission and filled it with about 1.5 quarts of ATF.

About 1 cup of ATF dripped out of the transmission from an area below the rear transmission seal. I used a fiber optic camera in an attempt to verify where the drip was coming from but could only isolate to a low point under the rear of the transmission, below the seal. I will check the shifter's rubber seal in hopes that it is the problem.

I purchased a new Lenco transmission oil cooler and will complete the installation this AM. Bye the way, Jesse was great. I ordered the wrong unit and Jesse sent me the correct one without waiting for the return of the erroneous cooler.

Once I have installed a new low oil pressure switch, I will run the engine and operate the transmission in forward and reverse. I will place a oil absorption pad below the transmission to catch any ATF. Then I will know more. If the leak continues, I will likely need to replace the transmission's rear seal.

It is a BW and I hope I can change the seal while in the water.

I also intend to pressure test the old oil cooler. I am not 100% convinced it is the reason for the water in the transmission. I have pressure washed the engine and could have forced water under the cap into the transmission by accident.

Flush out the contamination thoroughly!

Is the rear seal of my BW Velvet Drive bad?

I ran the engine with the tranny in forward and reverse, then pumped out the contaminated ATF.

I filled the transmission with 2 quarts of ATF with a plastic paint container setting under the rear of the transmission. The next day I found 12 oz of ATF in the container. This leaves about 52 oz of ATF in the transmission.

The dip stick gauge shows about half way between low and full.

The transmission shifted positively and smoothly in both directions.

I am getting ready to run the engine again to verify I got all of the water out of the transmission.

The last time I ran it, no additional ATF came out of the transmission.

Your thoughts are appreciated.

Although it is certainly possible that the dilution thinned the oil causing it to leak, it seems more likely to me that it merely caused it to leak more rapidly. I suspect it is still leaking, maybe just more slowly.

Keep an eye. In my observation the biggest cause of these transmissions needing to be rebuilt, sometimes exhaustively, in recreational units is operation with low fluid due to unrepaired leaks.

Pulling it apart to inspect and reseal is expensive. Pulling it apart to rebuild is more expensive.

PNM said:

I purchased a new Lenco transmission oil cooler and will complete the installation this AM. Bye the way, Jesse was great. I ordered the wrong unit and Jesse sent me the correct one without waiting for the return of the erroneous cooler.

Click to expand...

Which Lenco? The trim table and controls folks?

I rebuilt a Velvet Drive myself as a preventive maintenance task. It seemed to run fine, oil looked good but it was getting on in years as it was 26 years old.
Upon disassembly I saw the the reverse cylinder had a rust area in an approximate 60 degree arc on the upper part of the cylinder that was preventing the cylinder from moving evenly in the bore.
I fixed it with emery cloth and put it all back together with some new parts, etc.
I took the tranny to an "experienced timer" who probably rebuilt a couple hundred VD gears to do a bench test.
He did and it was fine but during the encounter he talked about these trannys.
He told me that if water ever gets into the reverse cylinder, the only way to get it out is to turn the tranny upside down and drain it out.
I don't know if that really true or not, but this gentleman knew his stuff.
I changed my tranny coolers often after that discussion.
YMMV.

https://www.lencocoolers.com/ from NY, USA.

Changing the Rear Seal on a BW Velvet Drive

I found a great video on utube showing exactly how to change the rear seal. However, I am in the water and don't think I can move the prop shaft to the rear about 6" to remove the hub spline.

I have heard I can jack up the rear of the Perkins 6.354 to clear the prop shaft hub and replace the seal.

Any experience or recommendations about this idea will be appreciated.

After you get the new seal in, do a couple more flushes/run/flush, looking for milky oil.
Don’t forget to test the cooler ASAP, and remember that the bargain priced copper coolers are not noted for their longevity!

Jacking up and engine to get access to a rear seal

Thanks, much!

Do you have any recommendations regarding jacking up the engine to get access to the rear seal, while in the water?

Remove the top nuts, but don’t move the lower nuts on the mounts.
This should help put you in the ballpark for realignment after it all goes back together.
Sometimes it’s feasible to lift the mounts with the motor, but either way, alignment should be checked after.
I’ve done minor engine lifts with just a crowbar and some scraps of wood, just keep it coming up equally in small increments.
The propeller shaft should slide back enough to remove the shaft side coupling, saving a couple more inches.

Lifting rear of engine to replace reduction gear seal

thanks