R 25 Classic Twin Disk

[peterd@btsi.tv]

I am new to the Ranger Tug world. I have purchased a 2009 25 Classic with the Cummins 150 and Twin Disc transmission. My problem is that in neutral the prop shaft still turns about 20-30 RPM. It is enough to creep the boat along and makes docking a bit tricky. I have checked the oil it is clear, and appears to be at the proper level. I have heard of putting a pressure gauge on the transmission, has anyone done this?

I have also fiddled with the linkage and as I slowly move the lever the shaft slows a little but then goes in gear. I can't find a position where it fully stops.

The oil smells OK, no burn smell.

Ideas and information would be greatly appreciated.

 

[Bruce Moore]

Bumping post delayed in moderation queue.

 

[Ralf H]

Hi Peter,

Forgive me if I am a little late to the party (have only been with the company for 7 years and am not 100% familiar with the older boats) but I do not have any recollection of us having Cummins engines on our boats. The early boats were delivered with Yanmar engines. Having said that, I have not heard of any creep issues like you have described and would therefore recommend consultation with the manufacturer. From your description it does appear that the issue may be with the shift linkage, but that still needs some diagnosis. Sorry that I can't be of more help at the moment, but please let us know if you have any additional questions on this.

Cheers,

Ralf

 

[scross]

Ralph,
The 150 hp Cummins-Mercury QSD Diesel engine was an option for the R25 Classic between 2008 and 2010 I believe. There are a fair number of R25 Classics of that period which have that engine.

 

[knotflying]

Did you check to see if the prop was turning because of engine engagement or just water passing by the prop? Current and wind while in idle will make the prop turn

 

[NorthernFocus]

Not sure what happened to my reply to this topic. It was there but now it's gone. I'll try again.

We have the same boat, same engine. The gear spins fast enough when run out of the water that I feel compelled to stick a brush handle in the wheel to stop it to avoid potential wear on the packing. But in the water it barely rolls. Fiddling with the shift linkage brought no joy but since it's not an issue with the boat in the water I quit worrying about it. Marine gears rolling a little with no load is not unusual and typically not a problem. But if it's spinning enough in the water to move the boat it is certainly an issue.

If you have a marine gear shop in your area and are a DIY guy the gear doesn't weigh much and is fairly easy to pull. The labor of pulling/re-installing the gear is probably at least half the cost of the job.

 

[peterd@btsi.tv]

Further info on this. It is pushing the boat and showing prop wash at the stern. I tried to stop the shaft with gentle (then firm) pressure from my foot on the shaft with no results. I worked with the linkage and it slows slightly as I approach reverse but then goes into reverse without stopping the forward turning.
I am working with a dealer in Houston on getting pricing for a rebuild, they initially had a hard time finding info on this as a MG 5005A, however I have found that it is the same as something called a Technodrive TM345A which is frequently offered packaged with small Cummins and BetaMarine engines. The disturbing part of this is that according to the manufacture the max input to the transmission should not exceed 110KW which is only 82 HP. The same spec lists a max HP of 130 for short duration. My engine is a 150.
In the 500 hours or so of operation, this transmission has been removed and repaired at least twice. I am now wondering if this is a result of overpowering?
I have also come to understand that a certain amount of rotation in neutral is not unusual for hydraulic transmissions.

Would love to hear from other owners of this engine/gear combo on their experiences.

 

[NorthernFocus]

I think you did hp conversion backwards. 110 kw = 146hp. We're at 1800 hours and counting on original transmission

 

[peterd@btsi.tv]

Thank you Northern Focus. You are correct, I did the math backwards. have you ever noticed the shaft turning in Neutral?

 

[NorthernFocus]

Thank you Northern Focus. You are correct, I did the math backwards. have you ever noticed the shaft turning in Neutral?

Yes ours turns slowly per my comments a couple posts back.

 

[peterd@btsi.tv]

As a final note on this. I was able to find a new-old transmission in stock at Mercruiser. Cost was less than a rebuild. Inventory tag indicated a test date of 2011. Unit was clearly new, unpainted and unused. Very well kept, no corrosion or anything on it.

I had the unit installed and all is well. No more turning shaft. Digging thru the service records for the boat I found references to replacing the drive plate AND clearing lines wrapped around the shaft and prop. It occurs to me that this could have been the cause of the transmission problem. Operating the transmission in gear with the prop and shaft impaired might overheat the clutch plates and warp them.

So my conclusion is that a correctly operating transmission should not be turning. FYI cost was about $2800 thru Crowley marine. Last check indicated one more in stock. They call it a Technodrive 345A, ID plate on new one said Twin Disc MG 5005A just like my old one.

 

[Levitation]

I have the same boat and tranny as the OP. In neutral it does not push the boat around. Usually it does not turn at all or just slowly creep a slow partial turn now and then - which I attribute to viscous coupling. I suspect your preliminary diagnosis of warped clutch plates is correct.

 

[PanaSeaAh]

Have the same boat, driveline and trans. It will "drift" in the forward direction in neutral, but not enough to move the boat. Glad you have found a fix. Have about 470 hours on ours.