View Full Version : Tran Problems/

07-10-2012, 10:07 AM
Hey Guys,
Picked up my first mastercraft 91 prostar the other day and got it out on the lake. the trany seems to be slipping some. rpms are up to 2000 before the boat seems to even move, as the rpm's reach about 3000 the boat will "launch" sometimes making a slipping noise as it leaves. I checked the fluids and have water in the trany for sure. pumped that out about 3 times and it seemed clear. back out to the lake and the boat moved at about 1200 rms and seemed good for a short period but then started back slipping shortly afterwords. I figure I have larger problems after reading some of the threads, the boat takes on alot of water(can run the bildge as much as 5-6 min to get it empty. Further inspection of the packing around the shaft showed where the prior owner used calking to try and stop the water flow. I feel like that would be the place to start but not real sure. im hoping that i don't need a trany this early in. Just looking for some pointers. Thanks for taking the time out of your busy day to answer my thread.

07-10-2012, 10:38 AM
You might want to start with getting the manual from the link below.


07-10-2012, 11:14 AM
Welcome to the forum.

Sounds like you need new shaft packing or may just need to tighten the shaft packing nut.

Pics of the location of the caulking would help, but self diagnosis is easy. Just pull the rear floor panel and put it in the water if it's in the shaft area you will be able to see it quickly.

Is the tranny fluid still clear?

07-10-2012, 11:21 AM
spoken like a pro! Or you could just come over to the house and help me your only 45 min away! The caulking is around the plate. Tranny fluid shows signs of more water but im sure I didn't get it all. Changed it 3x but never out on the lake after it was warmed up.