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woodrowskis 07-12-2011 07:24 PM

Sounds like rocks in my transmission
2002 Prostar 197 , 6.0 L with the ZF Hurth transmission

When in gear, transmission sounds like cement mixer at idle and barely above idle in both forward ands reverse. At first it was only in reverse. It is getting worse.
When I get up to speed it sounds fine unless the other noise is simpply covering it up.

I disconnected the the shift cable hoping that it needed adjusting and was not geting into to gear. However, the noise is still there without the cable connected and engaging the shift lever on the transmission by hand.

I looked at the fluid level. It is good. I ordered a filter and plan to change the fluid when it comes in. I did see all the comments about cleaning as opposed to buying but if that is the problem and it is this bad, I'll pay the $70 and get a new one. Can a clogged filter cause this sound? It seems possible since higher rpm (i.e. pressure and flow) seem to cure the problem.

Has anyone got any other ideas? It is sounding bad enough I'll bum a rides until I figure this out.

G-Star 07-12-2011 07:30 PM

How many hours on your boat?

Based on your description, my first guess would be the damper plate. Not terribly expensive, but a bit of a PITA to change out.

woodrowskis 07-12-2011 07:47 PM

right around 700 hours.

that would be cheap and I can do it. Any tricks to confirm without pulling the tranny?

G-Star 07-12-2011 07:59 PM

I'm afraid I don't know of any tricks. An experienced ear with a mechanic's stethoscope might help.

Jerseydave 07-12-2011 09:11 PM

I'm no expert, but if higher rpms make the noise go away, sounds like you need a damper plate. I wouldn't run her any more until you take care of it.

Be happy it's not a V-drive.....Prostars are much easier to work on.

dmminfla 07-12-2011 09:13 PM


Originally Posted by woodrowskis (Post 770869)
right around 700 hours.

that would be cheap and I can do it. Any tricks to confirm without pulling the tranny?

Pull the starter and look for metal shavings.

woodrowskis 07-14-2011 11:32 AM

thanks guys. I hope you are correct. I will pull the tranny in the next couple of days.
I will do my best to watch some posts to help others out and repay the favor.

I have had an 86 Mastercraft from 1989 til 2002 and and the 2002 from then until now.

trickskier 07-14-2011 07:02 PM


Originally Posted by dmminfla (Post 770898)
Pull the starter and look for metal shavings.


woodrowskis 07-15-2011 01:19 PM

I neglected to mention I do intend to pull the starter first.

I did have a starter failure on my 86 mastercraft and when I pulled it I found a piecce of spring from the damper plate. So I am familiar with this.
Question is, if I don't see anything, do I keep going?
I will be doing this tomorrow morning.

G-Star 07-15-2011 01:46 PM

Based on the "sounds like rocks in my transmission" comment, I think you've got not choice but to pull the transmission. Hopefully, as soon as you pull it you will just see a broken damper plate. If not, I guess your next step would be to crack the transmission and start looking for rocks. And you might as well replace your shaft seals if you've got the transmission apart.

But, I still think I'd take "Damper Plate" for "$400" please, Alex. Let us know how it works out.

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