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Skipper
10-03-2010, 01:38 PM
After an afternoon of skiing I thought I smelled burning transmission fluid. Sure enough, when I lifted the motor box I found a faint trace of transmission fluid on the side of the transmission and a small amount in the bilge below the transmission. It appeared to be coming out of the vent on the transmission. I am about to clean up the mess and try to figure out what happened.

I suspect that the transmission must have been getting hot to force fluid out the vent, especially when it smells burned. So I will start with the transmission cooler. The engine temperature remained normal at all times. So I am not sure how the transmission cooler could affect only the transmission but not the engine?

1995 Prostar 190
Standard EFI engine
Hurth 1:1 transmission
3 blade ACME prop

Any help would be greatly appreciated.

Angry Bill

Skipper
10-03-2010, 02:22 PM
What I have found so far:

1. The water strainer was clean and free of any obstructions.
2. The transmission cooler was clean and free of any obstructions.
3. The transmission fluid level was just less than 1/2 quart high.

I removed the extra transmission fluid to get it level with the dipstick. (not me, the one that mounts in the transmission).

I suppose the next check is to disconnect the transmission lines at the transmission and determine whether or not fluid flows through the transmission cooler? But I dunno?

I plan to replace the transmission fluid with new stuff and ensure that the level it correct. (I replaced it about 15 engine hours ago and I thought I put in exactly what I took out, dunno?)

Beyond that, I am at a loss on this mystery.

Any takers?

FrankSchwab
10-03-2010, 02:35 PM
Check for water in the transmission fluid. Perhaps the trans cooler has a crack internal that's encouraging water to enter the transmission - that would explain the high level.

/frank

ted shred
10-03-2010, 04:44 PM
If the transmission was overfilled, that will make it come out the vent. I had this quite often until I quit having the dealer service my boat and started doing it myself.

If it wasn't overfilled, then I would do what Frank said. Check for water contamination.

Skipper
10-03-2010, 06:10 PM
Used the suck pump to remove the old transmission fluid. No signs of water contamination. Put the new stuff in right to the level on the stick. I'll see what happens after the next couple of engine hours. If it gets more fluid in it again, then it must be a crack internal to the transmission cooler. Thanks for the advice. Ski well.

oldairboater
10-03-2010, 09:27 PM
Don't know about yours but my manual says to run the engine---shut down the engine and wait a few minutes then check level. I actually marked my dipstick for level when boat hasn't been ran. Now I just put back what I took out in volume --check the dipstick sitting there and then run the boat wait a few minutes and check the dipstick again. Hoping all three measurements work.

coz
10-03-2010, 10:08 PM
Don't know about yours but my manual says to run the engine---shut down the engine and wait a few minutes then check level..

Mine says warm the engine to operating temp then shut down and check imidiately to get the correct level.

JimN
10-03-2010, 10:12 PM
After an afternoon of skiing I thought I smelled burning transmission fluid. Sure enough, when I lifted the motor box I found a faint trace of transmission fluid on the side of the transmission and a small amount in the bilge below the transmission. It appeared to be coming out of the vent on the transmission. I am about to clean up the mess and try to figure out what happened.

I suspect that the transmission must have been getting hot to force fluid out the vent, especially when it smells burned. So I will start with the transmission cooler. The engine temperature remained normal at all times. So I am not sure how the transmission cooler could affect only the transmission but not the engine?

1995 Prostar 190
Standard EFI engine
Hurst 1:1 transmission
3 blade ACME prop

Any help would be greatly appreciated.

Angry Bill

When was the last time you cleaned out the oil cooler?

JMann
10-03-2010, 10:23 PM
Mine says to drive around and check the fluid immediately after running (not just warming the engine you need to warm the transmission).
If you didn't check your fluid with the transmission warm you may have over filled causing the fluid to blow out the vent. I will refill run around for 5 or 10 minutes then check, add if necessary.

oldairboater
10-04-2010, 10:01 AM
Your right--looked at my manual again says run engine. Shut down and check level immediately. I never hurry doing it. Mine says warm the engine to operating temp then shut down and check imidiately to get the correct level.

Skipper
10-04-2010, 07:09 PM
When was the last time you cleaned out the oil cooler?

Is that the transmission cooler that is connected to the intake hose and has two lines connected to the transmission? I have a pre-cooler water filter that I clean after every trip to the lake (usually only small deposits of pine needle sized debris) and I disconnect the water line at the transmission cooler to connect a water line to flush with fresh water every trip.

Skipper
10-09-2010, 09:12 PM
Ran the boat for several hours this afternoon. Checked the transmission fluid level after the first set and it was right on the line. Still had a small amount of transmission fluid venting out the vent. Really starting to bring out the angry in me.