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View Full Version : Help with 1988 ProStar 190 transmission slipping


charlieaf92
08-20-2010, 12:04 PM
We just got back from a houseboat trip and unfortunately our boat didn't perform as expected. It is a 1988 prostar 190 that was purchased new and has about 790 hours on it. Up until now we have only had 1 issue (waterpump impeller) - other than that the boat has been bullet proof.

This trip the problem began to present itself in the no wake zone - 1 click into forward. After a while the boat no longer went forward and we had to increase the throttle to keep moving. The problem got worse as the engine (and I'm assuming the transmission) warmed up. After sitting for a while, it would work fine - but after running for a few minutes the tranny began to slip. It really became noticeable when we were wakeboarding - to get back to the houseboat we had to run the engine at 3k just to keep moving and it began to smell. After that we kept it docked the rest of the trip.

The fluid level is fine (first thing we checked) and the fluid is red (not milky).

edit - I just read that there isn't actually a torque converter. Any advice about where to look would be appreciated.

Thanks in advance
charlie

JLeuck64
08-20-2010, 03:39 PM
Yup had that experience happen to me years ago with a nautique I used to own... Slipped in forward gear, but reverse was still working. At least it got us back to the marina... eventually! I opted to replace that trans with a rebuilt one at the time, but looking back I probably could have handled rebuilding it myself. Just didn't have the time and it was the middle of the season out here. Sounds like you have lost the forward clutch pack for some reason. THAT reason needs to be determined so it doesn't happen again. Would hate to see you go through the expense of this repair to have it happen a second time.

I would start by disconnecting the cable from the shift linkage and checking the movement of the shift lever on the trans manually. The shift cable should be moving the lever on the trans fully into both the forward and reverse positions.

There is a port for checking the internal pressure of the pump also. With the correct pressure gauge you can install it directly to the trans to monitor pump pressure while shifting into forward and reverse. Some one else should be able to help with the expected pressures to see, hopefully...

Those are the basics, beyond that would require disassembly to inspect the internals.

Bruce Carr
08-20-2010, 03:53 PM
I had that exact same issue years ago. It turned out that the oil pump inside the trans was wearing out. The trans oil pump supplies pressure to the clutch pack holding the clutch plates tightly together. If the oil pump can not maintain enough oil pressure the clutch plates can slip causing the heat you noticed and of course preventing full transfer of torque to the prop shaft. The full rebuild kit came with a new oil pump gear and housing along with the new clutch plates and seals. The rebuild can be performed by the relatively skilled and equiped home mechanic. Replace the damper plate as well when you have the trans removed. Also, I believe on your year model 351W engine, you can easily replace the engine rear main seal when the trans is off.

charlieaf92
08-20-2010, 10:03 PM
Thanks for the response guys. I am going to get a rebuild kit. Is there a good source for quality rebuild kits that you would recommend? This is a velvet drive 1:1

Thanks
charlie

thatsmrmastercraft
08-20-2010, 10:51 PM
Thanks for the response guys. I am going to get a rebuild kit. Is there a good source for quality rebuild kits that you would recommend? This is a velvet drive 1:1

Thanks
charlie

Discount Inboard Marine is a great place to work with for most things you could need for your Mastercraft.

http://skidim.com/

charlieaf92
08-24-2010, 01:13 AM
Well I removed the transmission this evening and found the damper was destroyed. I am thinking now that this was the source of the problems.

Here are a couple pictures. One is of the plate damper itself and the other is of some of the metal inside of the bell housing - there was quite a bit of broken spring metal in it.

charlie

dgilbreath
08-25-2010, 12:34 AM
Where did youbuy your rebuild kit?

CruisinGA
08-25-2010, 01:38 AM
So are you going to rebuild the transmission or just replace the damper?

charlieaf92
08-25-2010, 11:41 AM
I haven't ordered a rebuild kit yet. I have a damper on the way that should be here Friday. Removing the transmission was about a 1 day project and not too painful, so I am thinking about installing the damper and taking it to the lake to test it and then decide whether or not to rebuild.

charlie

CantRepeat
08-25-2010, 03:54 PM
Does the transmission fluid look bright red or redish brown? Did you smell the fuild? Does it have an kind of a burnt smell? If either of these are true I would change the fuild before I bought a rebuild kit.

charlieaf92
08-25-2010, 03:55 PM
Does the transmission fluid look bright red or redish brown? Did you smell the fuild? Does it have an kind of a burnt smell? If either of these are true I would change the fuild before I bought a rebuild kit.

Good question. The fluid looks pretty good - still a red color with maybe a hint of brown. I think changing the fluid while we have it out is definitely a good idea and I will do that as well.

Thanks
Charlie

CantRepeat
08-25-2010, 06:49 PM
Good question. The fluid looks pretty good - still a red color with maybe a hint of brown. I think changing the fluid while we have it out is definitely a good idea and I will do that as well.

Thanks
Charlie

Sweet.

I had some slippage in my 92 about 4 years after I got it. Change the fuild and it lasted about 4 more years before I had to rebuild it.

Good luck.

charlieaf92
09-01-2010, 12:26 AM
Well - we put the transmission back in with fresh fluid and a new damper plate and took the boat out tonight to test it.

At first, things felt good - but after a bit of driving we found that one click forward wasn't engaging. If we gave it a bit of gas, it would start going forward though.

One click backwards seemed to engage reverse correctly - but it wasn't happening with forward.

There may have also been some minor slipping when cruising, but it was difficult to tell. We did do a few slalom runs without any major noticeable issues.

So - any ideas? I suppose the linkage could be out of adjustment, but I don't think that is likely because we didn't mess with it.

Is there a way to visually tell if the clutches are bad? I think we are going to pull the tranny again this weekend and take it apart.

Thanks
charlie

Bert
09-01-2010, 12:45 AM
Well - we put the transmission back in with fresh fluid and a new damper plate and took the boat out tonight to test it.

At first, things felt good - but after a bit of driving we found that one click forward wasn't engaging. If we gave it a bit of gas, it would start going forward though.

One click backwards seemed to engage reverse correctly - but it wasn't happening with forward.

There may have also been some minor slipping when cruising, but it was difficult to tell. We did do a few slalom runs without any major noticeable issues.

So - any ideas? I suppose the linkage could be out of adjustment, but I don't think that is likely because we didn't mess with it.

Is there a way to visually tell if the clutches are bad? I think we are going to pull the tranny again this weekend and take it apart.

Thanks
charlie

Likely just needs to be adjusted. Did you try shifting into gear with lever on tranny? Just an idea to rule out cable adjustment.

charlieaf92
09-01-2010, 12:50 AM
Likely just needs to be adjusted. Did you try shifting into gear with lever on tranny? Just an idea to rule out cable adjustment.

Unfortunately we didn't think of that until we were on the way home. Is it possible to perform the test with the boat on the trailer?

charlie

Bert
09-01-2010, 12:55 AM
Unfortunately we didn't think of that until we were on the way home. Is it possible to perform the test with the boat on the trailer?

charlie
Gotta be in the lake. Is it a long way? I guess you could do it as long as you are watering the strut bearing.

charlieaf92
09-01-2010, 12:56 AM
Gotta be in the lake. Is it a long way? I guess you could do it as long as you are watering the strut bearing.

Its about 30 minutes each way - plus time putting it on and off the trailer. But it is easier than pulling the tranny again.

Thanks for the help - I'll try to make it out this week and give it a shot.

charlieaf92
09-05-2010, 08:30 PM
Quick update...

We took the piston/cylinder that is connected to the shifter arm out and cleaned it.

Then, we took the boat back to the lake today. At first, everything seems great - but once it is warmed up forward doesn't engage without pushing the throttle more. We tested moving the shifter arm manually to rule out an adjustment issue and had the same results.

It seems that forward is the problem and reverse works pretty much like it should.

Any ideas? From what I know it seems like it is an issue with the forward clutch and needs a new one. We are going to pull the tranny tomorrow and start to open it up.

charlie

T'sProstar
02-09-2014, 06:21 PM
Mine is doing the same thing after I moved the cable when replacing the floor. I'm going to make sure the cable goes back to the regular position but what type of oil or tranny fluid goes in? Thanks

mikeg205
02-09-2014, 06:24 PM
Mine is doing the same thing after I moved the cable when replacing the floor. I'm going to make sure the cable goes back to the regular position but what type of oil or tranny fluid goes in? Thanks

velvet drive or ZF hurth - but dexron III I believe - so Castrol Transmax Dexron VI works - dont use 100% synth.

charlieaf92
02-09-2014, 07:35 PM
Update for anyone else having this problem. It was due to the pump being worn out. After replacing the pump gears everything worked great. If we had had a pressure gauge and followed the trouble shooting steps it would have been obvious that the pressure was out of spec. Would have saved a lot of headache.

Razzys Wagon
02-09-2014, 10:33 PM
umm, im at 740 on mine.....think ill change the fluid before I go out this season.....just to be safe,,,