Starboard engine stuck in forward gear. ZF 280 IV Transmission

All was fine then while pulling anchor yesterday Starboard engine stuck in forward gear. ZF 280 IV Transmission fluid lever is full, clear, clean not smelling burnt ......
Shifted slowly forward neutral several time but still in forward ..... shifting to reverse stalls engine ..... lost for words here. Any simple suggestions to look at or items to check before call in a transmission expert, do not want to look to dumb nor have someone come in ans just say .. Well it is bad and you have to change out trany... HELP Please !

Same thing happened on a friends boats 2 years ago when trying to dock. Transmission just locked up in forward. No one would rebuild it. New replacement 8k. If it were my boat I would have pulled it myself, tore it apart and at least tried to fix it.

Typically that’s bad. That’s how these fail but I’m betting your cooler went bad and you have contamination. What did your last sample look like?

On the Cummins B-C series i hear if you are on original gear coolers its only a matter of time before they fail (particularly in salt). They are pretty inexpensive from Mr. Cool. I'll be doing mine in the off season while doing the aftercooler service, cheap insurance. The new ones come with zinc's which should help. Best of luck and hopefully the tranny isn't toast.

It would seem your forward clutches are warped and will not disengage. Consequently, when put in reverse, both forward and reverse are engaged thus stalling the engine. Heat is the culprit and heat is caused by partial engagement of the clutch pack and continual slipping of the clutches. A couple of things can cause this such as; low hydraulic pressure, air in the hydraulic system, less than full engagement from the shifter and sector valve.

Also I meant to respond earlier but they are totally rebuildable. All parts are available.

Well SOME TIMES YOU ARE LIVING IT JUST RIGHT and It seems that after a complete night is not sleeping flipping, flopping and turning I went back down the dock to see where my next investment was being diverted to ..... Once again surveyed the situation and took Mr. Hottoddies approach, meet the bull head on and lets just see what we have here! This Boat id clean we traveled a lot with it, just finished 1500 miles in May 2019 did a few very short trips locally and was making plans to head to Tampa in a few weeks till the spring and then up to Nashville for the summer..... If we need to do this replacement lets do it. Well of course I could not get a Transmission Mechanic to come over, he was tied up and MAYBE next week if I was lucky. Well I needed to clean up the boat after the Blue Angels weekend trip anyway and Mr. Hottoddie said tackle yourself! Thinking yep we can do this .... but while cleaning the Bridge I was thinking we drive this boat so carefully and maintenance is normally done well before it is call for, Transmission fluid is CLEAN, Filters are Clean, this is an electronic shifting system not mechanical system. Lets start with the simple things first and work up to building a hoist system to pull the tranny. ....... Well I must have had the luck of the Irish (although being Italian I would take any Luck available). No more suspense here look at the photos and it will be a lesson to remember. ..........................

Wasp Mud Daubers

completely blocking all the electrical gear shift switches .... Oh and the on the throttle side we had some Mud as well but not as much...Live and lean here only cost a loss of a full nights sleep and about 6 hours bridge cleaning work. Ah now for a good nights sleep.
THANK everybody for chiming and I hope my lesson learned will help some one in the future!

So what’s damage did they cause?

As for Damage !
well the major one was only the lost of one nights sleep, but it could have been catastrophic.
we were running on only one engine while docking and the wind was up at 15-18 kts, 1 million and 2 million yachts docked to the starboard and Port of my slip. Once again thankful that we went the extra cost and had add stern thruster installed awhile back as well as the larger amp Hr battery to the bow thruster.

No really.... at this time we see nothing wrong except that I do have to get back under both the shift and throttle covers with some long cotton cleaning swaps and completely clean out the small sticky pieces of daubber mud which were stopping the micro roller switches from sending the electrical signal to the solenoid valves on the transmission for forward and reverse. SO my lessen learned here start with the simple stuff and work up to the major components.

Chubby said:

As for Damage !
well the major one was only the lost of one nights sleep, but it could have been catastrophic.
we were running on only one engine while docking and the wind was up at 15-18 kts, 1 million and 2 million yachts docked to the starboard and Port of my slip. Once again thankful that we went the extra cost and had add stern thruster installed awhile back as well as the larger amp Hr battery to the bow thruster.

No really.... at this time we see nothing wrong except that I do have to get back under both the shift and throttle covers with some long cotton cleaning swaps and completely clean out the small sticky pieces of daubber mud which were stopping the micro roller switches from sending the electrical signal to the solenoid valves on the transmission for forward and reverse. SO my lessen learned here start with the simple stuff and work up to the major components.

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Now that is a new one for the books; so both reverse and forward switches were engaged at the same time?

No think what was happening was that the forward gear switch was stuck on from the daubber mud and would not release and the Glendinning system has a fail safe switching relay so that if one switch in engaged (stuck on) and you move to the other switch the Glendinning actually shuts that engine off. At least that is the way I understand the circuit and this is exactly what way happening to me. Forward was stuck on and every time I shifted to reverse the engine would stop running......

I found a source for these switches and posted it up about a year ago...they are cheap as I recall...