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velvet drive transmission problems

Printed From: CorrectCraftFan.com
Category: Repairs and Maintenance
Forum Name: Engine Repair
Forum Discription: Engine problems and solutions
URL: http://www.CorrectCraftFan.com/forum/forum_posts.asp?TID=50818
Printed Date: November-22-2024 at 2:33pm


Topic: velvet drive transmission problems
Posted By: apesofdoom
Subject: velvet drive transmission problems
Date Posted: August-06-2022 at 2:01am
Hey guys I'm in look for some help with my transmission before I put it all back together again. 

The short back story. I had low transmission fluid and the forward clutch pack burned up. I pulled the transmission out rebuilt it with a rebuild kit. Mostly everything looked to be in good shape besides the forward piston. It had been wearing on the input shaft snap ring and didn't have a bevel anymore. I cleaned up the bevel and reassembled the transmission. I everything felt smooth and was in working order when I reassembled the boat. We took the boat out for a test run and it worked great with no issues. The next time we took the boat out we went about 5 miles from the dock and after stopped we lost forward, we still have reverse though. Forward still kinda worked but it was just enough to keep up with the river's current. I didn't want to push the transmission to see if I could build pressure to see if I could get it work. Something was wrong and I didn't want to overheat the transmission again. luckily we got towed in back to the dock.

I was unable to test the transmission pressure as I was having difficulties removing the plug and was going to be pulling it out again to figure out what happened. I disassembled the transmission again today to see what was wrong. The fluid did have some metal in it again but to my surprise the forward clutches are still in good shape! At this point I'm going to replace some of the major components like the oil pump because I want to make sure it has adequate oil pressure. The big concerning factor is the metal that I was seeing is coming from the forward piston again, and I will be including pictures of what I'm concerned with. What I don't understand is why my forward piston is rubbing so bad and eating it's self alive. I'm afraid that if I replace the forward piston the new one will just do the same and eat itself. 

Here is a few pictures of some parts that I am concerned about. 

   
I am also curious my shifter selector valve if is in good shape. The cooler sleave does still slide easily. My main concern is with my forward piston is wearing like it is. I have checked my bushings in the output shat and they are not spun or have any grooves in them. I have it all torn apart right now so if there are anything I should take a picture of to check, let me know. 
 



Replies:
Posted By: fanofccfan
Date Posted: August-06-2022 at 8:34am
Did you replace the damper plate as well when you put it back together?  Many years ago i had a pump that looked like yours.....a little fuzzy metal on the gear and gear case......my damper was bad and I was too uninformed to know that it should have been replaced.  This was before the internet thingy was around so I had no one I could really ask.  I think by the time I got everything in running order a semester of college was about half the cost of the education I received from that 1990ish repair.  OuchLOL  The bad damper was putting excessive load on the input shaft and grinding the pump which in turn put metal in places it didnt belong.

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2004 196 LE Ski 1969 Marauder 19 1978 Ski


Posted By: KENO
Date Posted: August-06-2022 at 12:35pm
Considering how those grooves look in the pump housing and on the gears, I'd be wondering if your Forward and Reverse adapter that the pump mounts to is nice and smooth or all grooved up too.

The grooves allow discharge flow to short circuit to the suction side and reduce your pump output pressure and that's not a good thing.

How's your brass thrust washer?


Posted By: MrMcD
Date Posted: August-06-2022 at 1:01pm
After a failure like yours that puts metal into the tranny fluid all Trans shops advice to replace the Oil Cooler and Oil Cooler lines because metal will be trapped in those items.  Once you start the boat and use it that trapped metal finds its way into your rebuilt tranny and causes damage.  In Trucking and Automotive this is standard procedure.   I have not heard of any boat companies pushing this advice but my bet is it still applies.   Did you at least flush the trans cooler and lines?   Hope you figure this out quickly.
Mark


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Posted By: Gary S
Date Posted: August-06-2022 at 1:26pm
Originally posted by MrMcD MrMcD wrote:

   I have not heard of any boat companies pushing this advice but my bet is it still applies.  

Here you go Mark from Skidim-

Description:
This is a NEW transmission not Rebuilt. The 71C (10-17-XXX) is normally used with GM or Ford small block engines. 4" Diameter output shaft coupler and 26 splined input shaft. Uses Dexron III trans fluid. Pump is indexed for LH rotation, we can reindex to RH no charge, please remind us in the comment section.
*Factory warranty is void without a new or recently replaced cooler.


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http://www.correctcraftfan.com/diaries/details.asp?ID=1711&sort=&pagenum=1&yrstart=1966&yrend=1970" rel="nofollow - 69 Mustang HM SS
95 Nautique Super Sport


Posted By: Gary S
Date Posted: August-06-2022 at 1:28pm
Or Ebasic Power- A New cooler must be used when replacing your transmission!

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http://www.correctcraftfan.com/diaries/details.asp?ID=1711&sort=&pagenum=1&yrstart=1966&yrend=1970" rel="nofollow - 69 Mustang HM SS
95 Nautique Super Sport


Posted By: apesofdoom
Date Posted: August-06-2022 at 1:52pm
Originally posted by fanofccfan fanofccfan wrote:

Did you replace the damper plate as well when you put it back together?  Many years ago i had a pump that looked like yours.....a little fuzzy metal on the gear and gear case......my damper was bad and I was too uninformed to know that it should have been replaced.  This was before the internet thingy was around so I had no one I could really ask.  I think by the time I got everything in running order a semester of college was about half the cost of the education I received from that 1990ish repair.  OuchLOL  The bad damper was putting excessive load on the input shaft and grinding the pump which in turn put metal in places it didnt belong.

haven't looked at the damper plate. The motor and transmission didn't have any abnormal vibrations when it was running so I didn't think to look at it. I would think it would cause extra forward pressure on the transmission. 


Posted By: apesofdoom
Date Posted: August-06-2022 at 2:01pm
Originally posted by KENO KENO wrote:

Considering how those grooves look in the pump housing and on the gears, I'd be wondering if your Forward and Reverse adapter that the pump mounts to is nice and smooth or all grooved up too.

The grooves allow discharge flow to short circuit to the suction side and reduce your pump output pressure and that's not a good thing.

How's your brass thrust washer?

The brass thrust washer looks fine to me but I could be missing something. As for the other side of the oil pump, you can see where it has been riding but its definitely not as bad as the oil pump itself. My fingernail doesn't get hung up like it does on the pump housing. 


Posted By: apesofdoom
Date Posted: August-06-2022 at 2:06pm
Originally posted by MrMcD MrMcD wrote:

After a failure like yours that puts metal into the tranny fluid all Trans shops advice to replace the Oil Cooler and Oil Cooler lines because metal will be trapped in those items.  Once you start the boat and use it that trapped metal finds its way into your rebuilt tranny and causes damage.  In Trucking and Automotive this is standard procedure.   I have not heard of any boat companies pushing this advice but my bet is it still applies.   Did you at least flush the trans cooler and lines?   Hope you figure this out quickly.
Mark

I did flush the cooler and lines before I put it all back together. ok, ill order a new cooler and lines for when I put it back together. That's not a big deal. 


Posted By: FFImarine
Date Posted: November-11-2022 at 10:04pm
You have a problem that your just not seeing it’s best to send it to me for a rebuild cause odd issues like this are quite tough to diagnose with just pictures. I have replacement pistons in stock so let me know if you figured it out

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You break it I’ll fix it



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