Transmission Oil Coolers

[Freedomskeeper]

I replaced both transmission oil coolers today. It is an easy procedure and the cost was reasonable. I used parts from Mr. Cool.

In my case, and I imagine most are similar, there were 2 hose clamps to remove and replace, two hydraulic lines to remove, and two screws holding the unit to the transmission. I also drained and refilled the transmission fluid.

I was forced into action after the the starboard cooler failed. I first noticed strange white "foam" coming from the starboard exhaust when I started the engine. We stopped at a local sand bar for awhile  and when we got underway and I noticed the white "foam" again and a few minutes later there was a strange hum coming from the boat. When I pulled the transmission out of gear to maneuver at a fuel dock (with 3 knots of current) I got a surprise. My starboard transmission was not responding! Upon inspection it was full of water after one of the cooling tubes failed and allowed transmission fluid to mix with the raw water.

I drained the water from the transmission and completely filled the case with ATF to displace any residual water until I could replace the damaged parts.  Several fills and flushes later all is well. There does not appear to be any damage to the transmission and it is working as it should, but time will tell.

Now I will have to replace the oil coolers before an expensive failure happens!!!

[Freedomskeeper]

   

[Strongpersuader]

I replaced both transmission oil coolers today. It is an easy procedure and the cost was reasonable. I used parts from Mr. Cool.

In my case, and I imagine most are similar, there were 2 hose clamps to remove and replace, two hydraulic lines to remove, and two screws holding the unit to the transmission. I also drained and refilled the transmission fluid.

I was forced into action after the the starboard cooler failed. I first noticed strange white "foam" coming from the starboard exhaust when I started the engine. We stopped at a local sand bar for awhile  and when we got underway and I noticed the white "foam" again and a few minutes later there was a strange hum coming from the boat. When I pulled the transmission out of gear to maneuver at a fuel dock (with 3 knots of current) I got a surprise. My starboard transmission was not responding! Upon inspection it was full of water after one of the cooling tubes failed and allowed transmission fluid to mix with the raw water.

I drained the water from the transmission and completely filled the case with ATF to displace any residual water until I could replace the damaged parts.  Several fills and flushes later all is well. There does not appear to be any damage to the transmission and it is working as it should, but time will tell.

Now I will have to replace the oil coolers before an expensive failure happens!!!

Very good heads up post, glad you figured it out in time. This site is awesome!

[Uhehner]

I suggest you also change that rusty hose clamp while you are there. Use a magnet to make sure the clamp is all stainless.
Capt. George

[Freedomskeeper]

I suggest you also change that rusty hose clamp while you are there. Use a magnet to make sure the clamp is all stainless.
Capt. George

All clamps were replaced. I should have noted that the picture was of one of the old coolers. I also cleaned surface corrosion and applied a rust inhibiting coating where needed.

[Freedomskeeper]

As an update......The transmission on the side that the cooler failed (starboard) would operate normally for about 15-20 minutes then start slipping. It appeared that the transmission was loosing hydraulic pressure.

As the final step in maintenance on the transmissions I changed out the filters. After a test run all seems to be normal.

I hope that this helps someone in the future