Tranny went BOOOM!!

(parkcityxj) · (parkcityxj) **Join Date: Mar 2001** 06-05-2005, 2:49 PM

So I finally got the carb finally dialed in and she was running the best she ever has until..... Four of us each got a set in and I was pullin up a rider, all of a sudden... Booom and then nothing. Of course I had to get towed in.

Tranny fluid was good and there was no indication what so ever that the tranny was going to go. I can freely spin the prop by hand too

It's a Velvet Drive 1:1. Hopefully I don't need an entire new tranny... Any suggestions before I tear it apart tomorrow?

(peter_c) · (peter_c) **Join Date: Sep 2001** 06-05-2005, 4:01 PM

Check the coupler connections to the trans...

(parkcityxj) · (parkcityxj) **Join Date: Mar 2001** 06-05-2005, 4:41 PM

It's def someting on the inside of the trans. I can hear it making noise whie spinning the prop. Something surely broke while under load. Never had any trans problems before and always changed/checked the fluid regulary.

powerstroke 06-05-2005, 5:03 PM

i think there is a shear pin i would check that first!!!!

(thane_dogg) · (thane_dogg) **Join Date: Jun 2002** 06-05-2005, 6:56 PM

pray it's the shear pin.

(parkcityxj) · (parkcityxj) **Join Date: Mar 2001** 06-05-2005, 7:05 PM

Thanks for the replies. What does this shear pin do and where is it located?

The thing that is weird is that I only had the sacs 1/2 full because we were trying to conserve fuel and it was running strong prior to breaking.

(Message edited by parkcityxj on June 05, 2005)

(riverdog) · (riverdog) **Join Date: Dec 2004** 06-05-2005, 7:38 PM

It might be the damping plate between the tranny and motor has let go. It connects the motor and tranny and has springs in it to dampen the shock when the boat is put in gear. Mine went on my old supra without warning one day. Pulled the tranny and it was a cheap and easy fix. Hopefully thats all it was. Good luck.

(rodmcinnis) · (rodmcinnis) **Join Date: Sep 2002** 06-06-2005, 2:06 PM

The Velvet Drives that I have torn apart didn't have any shear pin inside. Inspect the coupler between the shaft and the transmission carefully. Depending on your setup and transmission you may not even be able to see the transmission shaft as it could be entirely covered by the coupler.

The trannys that I have torn apart were all direct drive units, and I remember them as having the coupler bolted to the end of a splined shaft. Unless the coupler just plain broke then there isn't anything that could shear.

It is also possible that your coupler isn't on a splined shaft but rather a keyed shaft. It is possible that the the "key" that pins the coupler to the transmission shaft has sheared off, which is like having a shear pin but it wasn't intended to work that way. If it has sheared, you might get away with just replacing the pin, but it might have really messed up the coupler and/or transmission shaft.

When the engine is running, do you hear any sound from the transmission when you shift from forward to reverse? If the transmission was still coupled to the engine then I would expect to hear some gear whine, especially when you shift to reverse. If there is no noticable noise, then I would concur with Peter regarding the coupler. I have broken flex plates before so I know it can happen.

If you get any reaction from the transmission at all, and you are sure the the output shaft is not spinning then something dramatic has happened inside the transmission. I have rebuilt a couple of these, and I can't imagin what it could be. I can imagin losing forward or reverse, but not both at the same time.

If you are a "do it yourself" kind of guy then I would recommend that you start by pulling the shaft and removing the coupling from the transmission. Completely, not just separating the coupling.

If the problem turns out to be the flex plate (engine to transmission connection) then replace it and assume that it was a faulty flex plate.

If the problem was with the shaft to transmission coupler then check the shaft alignment carefully when you put things back. If things don't line up well then the constant flex and strain will eventually break something.

If something inside the transmission broke then I don't know what to advise. I would expect clutches to burn out long before something broke.

Rod

(jrandol) · (jrandol) **Join Date: Mar 2004** 06-06-2005, 6:25 PM

Does it make a rattling sound? If so, I wager a dampener plate. $95 part and about 2 hours of labor, 1 if you know what you are doing.

(parkcityxj) · (parkcityxj) **Join Date: Mar 2001** 06-06-2005, 9:28 PM

Well after about 6 hours of monkeying around, mainly scratching our heads, pulling the engine and tranny I found this to be the problem. Is this the flex plate?

(riverdog) · (riverdog) **Join Date: Dec 2004** 06-06-2005, 9:44 PM

Thats the dampening plate. Yep

(peter_c) · (peter_c) **Join Date: Sep 2001** 06-06-2005, 11:57 PM

Gotta love that easy/cheap fix :-)

Nice job calling it Rod!

(ralph) · (ralph) **Join Date: Apr 2002** 06-07-2005, 12:16 AM

$90 Yay!
http://www.skidim.com/prodinfo.asp?number=R140001

(parkcityxj) · (parkcityxj) **Join Date: Mar 2001** 06-07-2005, 12:18 AM

Thanks for help guys! Any idea what would have caused this? I'm assuming just old age, it is almost 20 years old.

Any reccomendations on where to get it cheap?

(jrandol) · (jrandol) **Join Date: Mar 2004** 06-07-2005, 4:28 AM

Skidim is your best bet as they usually stock them and they are fair priced. Looks like you have a Ford 351 or 302 Engine right?

(rodmcinnis) · (rodmcinnis) **Join Date: Sep 2002** 06-07-2005, 4:25 PM

I haven't seen a flex plate break like that before. I would have expected that to make a hell of a noise whenever the engine was running and you put it in gear!

My dad's boat broke a flex plate once many years ago, but it ripped the entire center secion free leaving only small pads under the bolts that held it to the flywheel.

Glad it wasn't anything super expensive! Just get a new one and get back to boating by the weekend!