Transmission cooler...need advice

jackson

jackson

Member
Nov 20, 2006
171
Narraganset Bay
Boat Info
2002 310DA
Engines
350 MAG Horizons/V-drives
My port side shift cable just started getting a little stiff when shifting. I checked the tranny fluid and it is very milky. I will replace the cooler tomorrow, and do the other side as well even though the fluid likes fine, and change the fluid a few times to hopefully clean it all out. My question is, because this seems like it just started and I haven't seen major issues, will I be good to replace the cooler, the filter and fluid? Can I get away without pulling and inspecting the tranny at this point? I have also found a little black around that side exhaust port. (It is the ZF Hurth 630V)
 
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Yes. Just drain it thru the plug in the bottom, not by a dipstick pump. Let it drip over night. Then refill with fresh transmission fluid and go run the boat long enough to get the transmission warm......like an hour +. Drain it again just as before then refill with fresh transmission fluid. THen before you winterize the boat, run it for an hour os so and drain the fluid and fill with fresh transmission fluid before putter her up for the winter.

Aalso, if you have a washable filter screen, then you only need to soak the filter overnight in mineral spirits while you are draining the transmission.
 
fwebster said:
Yes. Just drain it thru the plug in the bottom, not by a dipstick pump. Let it drip over night. Then refill with fresh transmission fluid and go run the boat long enough to get the transmission warm......like an hour +. Drain it again just as before then refill with fresh transmission fluid. THen before you winterize the boat, run it for an hour os so and drain the fluid and fill with fresh transmission fluid before putter her up for the winter.

Aalso, if you have a washable filter screen, then you only need to soak the filter overnight in mineral spirits while you are draining the transmission.
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Awesome....exactly what I was hoping to hear. Thank you!
 
I just went thru this.
You're not going to get anything big enough to catch all the fluid especially if its milky.
Water is in there also so the fluid level will be higher.
I unscrewed the dipstick to let the vacum vent then screwed it back in.
Used a red solo cup undid the drain plug and would screw it back in when cup was almost full.
Leaving the dipstick in won't let air in so the fluid will not rush out when plug is undone.
I had to drain and refill 4 times until fluid was clean.
I changed my filter also.
 
Did this last year. Same issue. Did I couldn't even tell you how many fluid changes. But I'm still up and running a couple hundred hours later. I would replace with Mr coil trans coolers. Remember if u have oil coolers I would change them as well. The same amount of water flows through them as does your trans coolers and there basically the same thing so they might let go soon as well
 
Thanks guys. I'm going to tackle this over the next couple days. I picked up the tranny cooler today, but went with Mercruiser. Not cheap. I wasn't sure if I should go with aftermarket so went with Mercruiser. I did see the Mr. Cool coolers online and they were a lot cheaper.
 
Thank you for all the help so far. Here is the update...I replaced the cooler and changed the fluid 6 times, filter once. Fluid looks excellent. I was shifting fine at idle speed, but when I put it under load it was skipping and had no power. After that it seemed to not be shifting even at idle speed. After it cooled down a little it was shifting at idle speed but seemed to be very weak. I couldn't hear it engage like normal and didn't have much power. Is it possible that it could be the pump? I am doubting that I did that much damage to the transmission itself to cause this. If it is the pump, can that be changed without pulling the tranny? Or am I better off pulling it and having it looked at. Thank you!
 
jackson said:
Anything seems to be possible lately, but no, I used Dex III ATF.
Click to expand...

Did u add the proper amount of fluid? Remember you have to add extra fluid because you removed the cooler as well. Try adding fluid even if you think you are over filling it and c if u get your power then.
How long was there water in your trans?
 
Xplicitlnck said:
Did u add the proper amount of fluid? Remember you have to add extra fluid because you removed the cooler as well. Try adding fluid even if you think you are over filling it and c if u get your power then.
How long was there water in your trans?
Click to expand...

Thank you for the advice. I will check the fluid again for the hell of it. I did speak with a local transmission shop today and described the issues. They believe it will most likely need to be rebuilt, or if the pump is bad then a new transmission. I think the water had only been in there this season and I've only put a few hours on it before the issue, so I didn't think it would cause that much damage.
 
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