2004 340 Transmission removal, without pulling engine thread.

mnm99

Well-Known Member
Oct 2, 2015
2,445
Long Island
Boat Info
2004 340 SeaRay Sundancer
Engines
Twin 8.1 Merc
Hi guys,
I thought I would post the process how I'm going to remove a V-Drive while the engine is still in the boat. I was told it can't be done, but I'm stubborn. So far all my clearances look like they will work. I'm going to do it a little different. First off I need to support the engine so it doesn't tip forward. The way I'm going to do this is with a beam from side to side with an additional support in the engine bay. Using a 500 lb come along just enough to take the pressure off the trans. Next is to add an addition I beam with another come along for the trans. There is a problem with separating, it's the trans mount. The way I'm getting around this is to remove the stringer bolt instead of the trans mount bolt. This will give me the ability to slide the trans back. NOW.. I have 4.25 inches from the back of the trans and the wall. In the diagrams I have the transmission mounting flange and the shaft is only 2.5 inches long(pic) so in theory I will be able to slide the trans back enough to disconnect from the engine. Then will have to go back and remove the bell housing. I'll keep you updated. So far I'm all unbolted and supports are built. The weekend after next is when I'm going to give it a try. ( WOW..I have a good camera. Don't mind the dirty engine and trans. Getting a good cleaning when done)
thumbnail (2).jpg
thumbnail (3).jpg
thumbnail (4).jpg
thumbnail (1).jpg
View attachment 62127
tr.jpg

View attachment 62129
thumbnail (5).jpg
 
Last edited:
Pretty ambitious and clever. I can’t wait to see how this plays out!
 
your challenge will be getting to the side and bottom bolts of the trans
 
Then will have to go back and remove the bell housing.

You need access to the dust cover bolts first to remove the dust cover before removing the rear housing
Also need to slide back the shaft coupling that 4 inches or so. That might cause the prop to hit the rudder.So you might have to remove the prop to get the coupling and shaft to slide rearward
By the time your ready you could have pulled it as a complete package with a boom
 
Then will have to go back and remove the bell housing.

You need access to the dust cover bolts first to remove the dust cover before removing the rear housing
Also need to slide back the shaft coupling that 4 inches or so. That might cause the prop to hit the rudder.So you might have to remove the prop to get the coupling and shaft to slide rearward
By the time your ready you could have pulled it as a complete package with a boom
Edit..Cover is removed.
 
Last edited:
The transmission has a splined snout on the input shaft so you will need to have the ability to wiggle the transmission from side to side and in a circular motion to get it free from the tortional coupler. You plan to leave the front engine/transmission mount in place is going to prevent much side to side movement. You may want to mark the engine/transmission mount bolts and nuts so you can remove the upper part of the mount connected to the transmission.

The ZF 630IV design is such that the shaft passes completely thru the transmission output flange and couples on the front of the transmission. I suspect the shaft on a 340DA will have to be pulled all the way back to the shaft tube to get the transmission clear of the end of the shaft. That will mean removing the shaft side of the coupler off and pulling of the prop and probably the shaft seal because the shaft will have to move back farther than the 4.25" it takes to clear the bulkhead in front of the transmission.....I"m guessing more like 8" to 10".

An ambitious back yard project for sure......good luck with it.
 
Not touching the side or bottom bolts. The 2 stringer bolts will remove the entire mount and bracket.

The trans is connected to the rear motor housing by 2 bolts and 4 nuts, You said to remove the trans and then the rear housing. It dosen`t work that way. There is a tin or plastic dust cover at the very bottom of the rear housing . Unless removed the flywheel will interfere with housing removal.
 
WOW will be following this ambitious project, good luck!
 
Not touching the side or bottom bolts. The 2 stringer bolts will remove the entire mount and bracket.

The trans is connected to the rear motor housing by 2 bolts and 4 nuts, You said to remove the trans and then the rear housing. It dosen`t work that way. There is a tin or plastic dust cover at the very bottom of the rear housing . Unless removed the flywheel will interfere with housing removal.

First let me clear this. A few of you mentioned the shaft. As of right now there is NO shaft in the boat. I took off the coupler and removed the shaft. It's in my garage right now. I have aligned my shafts a couple times before, so I know all about how to do that and what's involved.
Tell me about the dust cover. I'm trying to understand this. The trans is connected by 2 bolts and 4 nuts. Just say the engine was out of the boat for now. If those 6 were unbolted the trans should just pull out, right? Now the flywheel housing is connected to the block with 7 housing bolts. The housing shield should be able to be removed also bu reaching behind?? Either way I'll have access once I wiggle out the trans.
housing.jpg
housing1.jpg
 
Last edited:
I was thinking about that damn flywheel dust cover shield last night..lol. I ended up waking up at 4:30am this morning without my alarm. I don't have to be at work till 7am . I said what the hell..Put my cloths on in 40* weather, went out to the boat and 5 min later the shield was off. No sh**, that fast. Bring it on..Next challenge.. LOL.:D
Shield 2.jpg
Shield.jpg
 
Last edited:
Looks like it will work. Why are you pulling the trans?
This is why I'm pulling it. ( please all, let's not get into why it happened. No hydrolock ect..The starter was defective)

And to answer this question..Bt Doctor.."By the time your ready you could have pulled it as a complete package with a boom" My reason is, I can't go through the winter Knowing it has to get done, I'm impatient, And It will save me $700 for 1 haul less to the yard and time for the boom. AND..I was told it can't be done!
Flywheel.jpg
 
Not touching the side or bottom bolts. The 2 stringer bolts will remove the entire mount and bracket.

But, the aluminum part touching the stringer is really an aluminum angle with a piece of flat stock on the inside of the stringer as a backing plate. This means the stringers are captured between the port and stbd aluminum angles which substantially limits the ability to move the transmission separate from the engine or to move it away from the engine toward the bulkhead. The OP thinks he will be able slide the transmission forward to gain the clearance needed to separate the engine and transmission. I think some wiggling and even a slight rotation will be required to get the splines to release where he can separate the 2, and this will be difficult with the engine mount aluminum angles in place.

Maybe I'm wrong, but I've done this on a 450DA with HWS 800 IV/'s gears and the transmission had to be encouraged to separate from the engine by a good bit of wiggling and gentle persuasion with a pry bar.
 
But, the aluminum part touching the stringer is really an aluminum angle with a piece of flat stock on the inside of the stringer as a backing plate. This means the stringers are captured between the port and stbd aluminum angles which substantially limits the ability to move the transmission separate from the engine or to move it away from the engine toward the bulkhead. The OP thinks he will be able slide the transmission forward to gain the clearance needed to separate the engine and transmission. I think some wiggling and even a slight rotation will be required to get the splines to release where he can separate the 2, and this will be difficult with the engine mount aluminum angles in place.

Maybe I'm wrong, but I've done this on a 450DA with HWS 800 IV/'s gears and the transmission had to be encouraged to separate from the engine by a good bit of wiggling and gentle persuasion with a pry bar.

I totally understand what your saying. I'm sure I will be using a pry bar. I also may have to loosen up the side to side adjuster on the trans. That will give me the movement I need to wiggle. The angle bracket is on the outside of the stringer, Good thing. I'll have plenty of up and down wiggle. Well see soon..
tr.jpg
 

Forum statistics

Threads
112,948
Messages
1,422,818
Members
60,930
Latest member
Ebrown69
Back
Top