Loss of Reverse Gear in RT 25SC

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I’m on the Great Loop and two weeks ago, I lost my transmission while traveling between Alpena and Cheboygan, Michigan. I was cruising along at about 2500 rpm and felt a “stumble.” I pulled the engine back to idle and tried to assess what the issue was. I had no propulsion in forward or reverse. I was dead in the water. I called for a tow, which I have detailed in a Facebook posting in the TugNuts group, so I won’t go into it here. I was towed into a port with no maintenance facilities, and was not able to make contact with a mobile service person. They didn’t even call me back. I arranged to get towed to a marina in Cheboygan.

When the transmission oil filter was removed, there were obvious chunks of metal and shaking the filter sounded like a child’s rattle. Not a sound you ever want to hear. The parts guy at the marina contacts Volvo to find a replacement and there is only one available anywhere in the Volvo system, and it’s in Sweden…and it’s $10,400!!! Total cost for the repair was just shy of $12,000. For me, that was a trip ending amount. I would have to load the boat on the trailer and head home to the PNW.

It was up to me to find a replacement. Of course, the internet was the first stop with none showing up anywhere. I then tried finding a rebuild shop….4 to 5 months.

I remember reading on TugNuts that the Volvo box is made by ZF, and luckily the first ZF dealer I talked to was extremely knowledgably about ZF and Volvos. It turns out that the Volvo D3 transmission HS45A EC is a ZF 45A EC and unless you have a trolling valve, it’s a direct replacement. Unfortunately, the only one available right then was in Everett, WA and while we were trying to figure out the details, it was sold. The cost of the ZF, shipped to Michigan was going to be $3200. Quite a difference from the Volvo.

I had tried to make contact with RT at the beginning of this, and got a call back from Kenny Marrs. He went out to their storage container and happened to find a transmission left over from when they changed the engines in the last few 25SCs to 170 hp. I got it shipped to me and installed on Friday. It took the technician about 45 minutes to remove the old one, and about an hour and a half to prep and install the new one. When we went to start, we discovered that the engine was hydrolocked. We got that fixed and she runs fine, but I will discuss that in another thread.

The boat has less than 800 hours on it and has been regularly serviced, in fact less than 20 hours before this. I bought the boat with about 300 hours on it, so I don’t know of any previous damage, but there hasn’t been any since I’ve owned it. The solenoids were replaced with the new style 300 hours ago. We won’t know exactly what happened until I get it rebuilt sometime this next winter.

I hope you never have to go through this, but if you need a new transmission, I would recommend giving Mike Vogt, at Harbor Marine in Everett, WA a call.

Chris Boyd
2014 RT 25SC
Destined Nomad
Facebook Group: Destined Nomad

 

[trailertrawlerkismet]

Glad that you’re back on the water. Good call on getting ahold of RT and to Kenny coming thru for you. If you get to Traverse City and need anything, give me a call.

Jim F

 

[knotflying]

A good ending for you! And a big shout out to Ranger Tug for saving the day. A sad commentary for Volvo.

 

[BB marine]

Yes the HS 45A is a ZF reverses gear. It is amazing what Volvo marks up on their parts. They are really proud of their product. The ZF 45 A can be found used in the 1500.00 range but there are not many available because they are basically a throw way gear housings when damaged. I talked to Federal Marine service in the Chicago land area ( The owner has been in business for 45 years, if you had a Chris Craft with a Paragon you heard of them). They have been servicing ZF gears for years. He told me we don't rebuild many of the 45A series because the rebuild cost as much as a new one. Aluminum housings usually get damaged during a complete failure. He did tell me that the most common cause of failures is engine to shaft misalignment, the use of after market filters, improper installation of the filter during a fluid change and lack of recommended intervals of fluid change.

Installing the filter properly is easy but many service centers do not do it right. The filter must be installed to the cover slid on to the cover o-ring. Do not set the filter into the housing and fit the cover to the filter. There is a good chance of clutch failure if it is done this way. The reverse gear should be filled through the filter housing side and checked on the dip stick side.

Comparing an after market filter to a ZF filter will show you why you don't want to use after market filters. There is a noticeable difference if you really look at them.

Alignment!! If the shaft alignment is out it will greatly reduce the longevity of the reverse gear.

Cudo's to Fluid Motion getting you the gear.

I hope you have smooth sailing. We live in Lemont Il. Send me a PM when you get on this side of the Lake. We are closing on a boat that at Port Washington Marina, Wis. this week and plan to start heading to the Illinois River in about two weeks. Maybe we will see you out there.

 

[Rednuke1]

Anyone know who manufactures the reverse gear for the Volvo Penta D-4?

 

[BB marine]

Anyone know who manufactures the reverse gear for the Volvo Penta D-4?

ZF

 

[Rednuke1]

Thanks BB...

 

[Mr Ben]

Mr BB, I to have a 25sc with the 45. I changed my fluid and filter this spring with about 200 hrs. I'm sure it had never been done. The fluid looked like the new stuff I put in. Im not sure of the brand of filter used. It was supplied by FM. I don't recall any special instructions as to how to place the filter in the housing. Seems to me it dropped right in as it came out. I do recall the cover is kind of a hokey set up IMO. Its has a big groove in it where the big fat o ring sits. The whole thing is kind of a friction fit . I know I had trouble with it, but it seems its not under pressure and just kind of seals the top. I do not recall any special instruction about which hole to put the new fluid in. Once the new fluid is in place and reads proper on the dip stick good is good no? I also own a Porshe and there is a lot of vodoo and special methodology that goes into working on those, is that the case here? When I bought this I weighed the diesel vs outboard. I knew the engine was basically disposable. Speed was not a concern so I figured I could repower for half the cost of an outboard. I found NIB d3 150 onIine for under 10k, did not consider the reverse gear. I'm really happy with the set up. The engine runs like a sewing machine at low rpm. I do wish it had a little more power. I had thought about a chip since the same engine makes 180-220 with some different software and maybe a bigger turbo etc. Just thinking outloud, I'll stick with what I have. I do appreciate you sharing your knowledge with us. I see you purchased a new vessel and are starting a new adventure. I hope you will continue to stay in touch and and post from time to time. Now i'm wondering if I need to go pull that goofy cover off and see if I installed something wrong. The fluid is right where it needs to be on the stick, and it goes forward and reverse without any weird noises. Please advise.

 

[BB marine]

I don't recall any special instructions as to how to place the filter in the housing. Seems to me it dropped right in as it came out.

Filter should have come out attached to the cover held to the cover by the o-ring fit. Filter should not be dropped in. Filter should be installed to the filter cover for a proper seal and fit.

I know I had trouble with it, but it seems its not under pressure and just kind of seals the top. I do not recall any special instruction about which hole to put the new fluid

The filter housing operates at a negative pressure; the gear-rotor oil pump draws oil through the filter from the filter's center through the filter's media to the outside of the filter. If there is a leak in that O-ring the oil will mix with air and will be detrimental to the pump pressure, clutch plates, and valve body.

I do not recall any special instruction about which hole to put the new fluid in

Owners manual and service manual - Measure out the correct quantity of oil and fill the reverse gear via the oil filter housing.






How to renew the lubricating oil of the ZF 45 A reverse gearboxNote: When the lubricating oil of the reverse gearbox is renewed, the filter element should also be renewed.
1.Turn the filler cap (W1) counter-clockwise with a 6 mm Allen Key (W2) and remove the cap together with THE FILTER THAT IS ATTACHED THE THE CAP
2.As there is no drain plug, the lubricating oil must be removed with a pump (X1). Connect a hose (X2)to the pump. Push the hose into the suction tube (X3) and down to the bottom of the housing. Operate the pump to remove the lubricating oil; approximately 2,0 litres (3.3 pints) 2.1 US quarts
3.The outside diameter of the hose must not be more than 16,0 mm (0.625 in) SUCK THE OIL OUT OF THE FILTER SIDE OF THE REVERSE GEAR.
4.Add 2,0 litres (3.3 pints) 2.1 US quarts of ATF transmission fluid, see Section 9. ADD THE OIL INTO THE FILTER SIDE OF THE REVERSE GEAR
5.Pull the filter element off the filler cap. Fit the TWO NEW 'O' RINGS ON TO THE CAP AND PUSH THE FILTER ELEMENT ONTO THE FILTER CAP
6.Fit the filter and filler cap assembly and turn the Allen Key clockwise to fasten the filler cap.
7.Turn the handle of the dipstick (Y1) counter-clockwise to release the dipstick. Remove the dipstick.Clean the dipstick and check the level of the lubricating oil. The level should be between the minimumand the maximum marks (Y2). Add more lubricating oil if necessary. Insert the dipstick and turn the handle clockwise to fasten it.
8.With the gear lever in the neutral position, run the engine at idle speed for a few minutes. This willensure that the lubricating oil has circulated around the oil cooler and its pipes. Stop the engine and check the oil level again. Add more oil, if necessary. Insert and fasten the dipstick. Caution: Some oil could flow back from the oil filter after the engine is stopped. This could cause the oil levelto be over the maximum mark on the dipstick. If this occurs do not remove the excess oil.Note: In service the level of the oil can be checked with the oil hot or cold. Always check the oil level beforethe transmission is used.

At this point you do not have any issues so the filter must have aligned with the ring and sealed. It is best to stall the filter to the cap to confirm it is sealed properly. You can use this information the next time you change the filter.

 

[Mr Ben]

Now I am wondering, I did this in early May along with the engine service. As I recall the cover came off and the filter was sitting the basket or transmission housing. I dropped the new one in and replaced the big o ring on the cover. I do not recall a secound o ring. I found an exploded parts diagram. I see it now. its still unclear how that attaches to the cover. I suppose it would be easy enough to go across the street where I keep the boat and pull the cover off again. It may be that it all went together as it should, but maybe not. The part I remember struggling with was getting the big o ring back in the housing. Maybe I was fighting the little one inside as well. I know I put the filter in the basket not on the cover as that is how it came out. I don't recall where I pumped from and added to. I did use close to the amount called for. I am right up to the full mark on the stick without screwing it in as the book says. Im going on 80 hours since I did this. I am still working up to changing the fuel filters. The book says do not prefill the filters. On all my other diesel engines I always prefill the fuel filter. My air filter looks clean from the outside. This is somewhat of a learning experience. I like working on my own stuff. I was a certified marine mechanic back when GPS was a military secret. Anyone remember radio direction finders and that new age loran C. Flathead gray marine were common.