Carver Owners Forum

Unfortunately the unthinkable happened!
The transmission oil cooler failed and I have a tranny that has to be replaced.
I had come back from a 2 hr cruise and checked the oil levels on the transmissions. The port side required 1/2 quart while the starboard read empty. I checked again and did not get a read so I tried adding fluid. As I was adding, the fluid was finding its way to the bilge and I knew something unfortunate was going on. My mechanic came down and determined that the fluid was not leaking out but rather the tranny was filled with water and the fluid had no where to go. Per the area marine transmission specialist, I pumped out the water, filled to top with fluid and flushed 2x going into forward and reverse. It seemed to be working and thought that I dodged a bullet.
I took her out for a run in order to change the fluid yet again but after about 20 minutes, it quit.
How does one avoid this mess in the future? Do any of you folks preemptively change the oil coolers for both transmissions and engines? I owned my last boat for 19 years, never changed the coolers and never had an issue.
All I know is that the lousy $140.00 oil cooler is gonna cost me about 5K!
I would be interested in knowing how you guys approach this.
Thanks.

denpooch wrote:Source of the post
I pumped out the water, filled to top with fluid and flushed 2x going into forward and reverse. It seemed to be working and thought that I dodged a bullet.
I took her out for a run in order to change the fluid yet again but after about 20 minutes, it quit.

Sorry to hear that, but I'm confused about what happened when "it quit". Did the tranny stop shifting? stop going into fwd or rev? lock up?

Hey KM. When it quit, the transmission would not respond to forward or reverse. It was like shifting when the engine is no running.
BTW, the tranny guy said that once contaminated I would have to pull the tranny. He knew... I was hopeful.

Bad luck there man....I agree with you about how to avoid it......I know all of my previous boats and maybe yours had the trans coolers on the suction side of the raw water system. Current one is like yours .
Before you went back out did you change out the cooler ?

Hi Bud,
Yes I did change the cooler, however, I did so after two 12 quart - idle at dock and change gear - flushes. I thought that I would be ok because it was working at the dock.
As we all seem to be subject to this problem, does anyone have suggestions on how to best avoid this from happening to any of us? One thought is to check tranny fluid after each use.... but even that will be after the fact.
Thanks.

I believe if the cooler was on the suction side ( between the thru hull and the pump ) it would have been virtually impossible for the trans to pull in the amount of water you experienced. Now that said, I am thinking these shared sump v drives may require a fair amount of cooling surface to keep temps under control, that may be too restrictive for the suction side and can only be on the pressure side.
Now after some thought perhaps one of the contributing factors could be an actual restriction ( buildup ) in the cooler causing the raw water pressure to be somewhat higher than normal there by overcoming the trans oil pressure....how did the inside of yours look, could you see how it failed ??..that seemed to be lot of water .
It really does seem to be a design problem. I have the same set up.

I couldn't tell from looking into the end of it.
I think that the oil cooler and fluid pump in some ways work independently. Check out page 60 of this manual; http://www.crusaderengines.com/wp-conte ... 510018.pdf
The transmission pumps the fluid 'into - out of' the cooler while the engine impeller draws the raw water through the transmission oil cooler. (there is also the gas cooler and engine oil cooler in series) It is easy to imagine that if there is rot in the fluid tubes or some catastrophic failure within the exchanger, the tranny circulation pump will draw raw water into the transmission. The loop will then send the fluid into raw water side of exchanger and out the exhaust.
I may be wrong but that's how it looks to me.
In speaking with Carver, this seems to be a standard design formula.

Bad luck there, it's unfortunate.

denpooch wrote:Source of the post....
How does one avoid this mess in the future?.....

The way to avoid this is to treat it with the same mindset as the engine coolant heat exchanger; in a salt water application, after 5-7 years, you're running on borrowed time, so replace before major damage occurs. Oil coolers are no different.

Yes Viper I think that has to be the way to avoid these expensive issues. I will immediately change out the engine oil coolers along with the non-affected tranny cooler. Next Spring I will do the engine heat exchangers before she goes in.
As a matter of clarification in earlier posts when I was speaking about flushing the engines, I did bypass the oil cooler by creating a loop outflow to inflow on the transmission fluid line. After the two flushes in this fashion I replaced the oil cooler.
Thanks to all for the conversation.

denpooch wrote:Source of the post I couldn't tell from looking into the end of it.
I think that the oil cooler and fluid pump in some ways work independently. Check out page 60 of this manual; http://www.crusaderengines.com/wp-conte ... 510018.pdf
The transmission pumps the fluid 'into - out of' the cooler while the engine impeller draws the raw water through the transmission oil cooler. (there is also the gas cooler and engine oil cooler in series) It is easy to imagine that if there is rot in the fluid tubes or some catastrophic failure within the exchanger, the tranny circulation pump will draw raw water into the transmission. The loop will then send the fluid into raw water side of exchanger and out the exhaust.
I may be wrong but that's how it looks to me.
In speaking with Carver, this seems to be a standard design formula.

Just for my clarification....do you not have the trans v- drive assembly pictured on page 58, that would be the same as mine.....in any case good luck with your trans change , hope they do a good job for you.