CAN'T GET TRANSMISSION OUT

[CaptFrankM]

I have a leak on the forward seal of my Velvet Drive 71 transmission, attached to a Cummins B3.3M engine. I need to get to the front end of the transmission. I have removed all of the bolts, connectors, etc, (except 1).

The problem is that I need the propeller shaft to move back about six inches in order to move the tranny back far enough to get at the front end. I cannot get the shaft to move more than about 3/4". Initially, I thought the problem was that I had a zinc anode too close to the strut, so I dove on the boat and removed the two furthest aft anodes, which should give me more than enough room, if I could get the shaft to slide back.

This transmission has been taken out four times by two different organizations, so I know that it can come out. I have tried putting a wedge between the transmission and the shaft coupling, tried pulling from underwater, used an air shim rated to 300 pounds - nothing has moved the shaft appreciably. Today, I jammed a piece of 1x4 between the couplings and put a 2 ton bottle jack about 2 feet away (against a bulkhead) and pushed the 1x4 aft - all I succeeded in doing was breaking the 1x4 (it may have moved 1/4 inch).

The other thing I have tried to do is to remove the plate that attaches between the engine and transmission, which is held on with a dozen Allen head bolts. I was able to remove all of the bolts except one, which is at the bottom inboard side of the plate. This one will not come out. I have tried using an electric impact driver, PB Blaster and a heat gun. Nothing is working. I can't get on it directly - it is between the engine stringers. I thought that maybe I had the plate at an angle, so I put back in some of the other bolts and tightened the transmission back into place. It took some of the pressure off, but the bolt still won't move.

I have run out of good ideas to get something (the transmission or the shaft) to move and am beginning to consider really stupid things. Before I do anything that I will end up regretting, I figured I would see if anyone had any ideas that I have not thought of yet.

Thanks.

[model 10]

Sometimes the splines on the trans front shaft wear into the splines of the drive plate. The only way to get it apart is to destroy the drive plate. Wedges between the bell housing etc will blow out the drive plate center hub.

[CaptFrankM]

I appreciate that - but my problem is that I can't get enough space to separate the two. The transmission actually moves back about 3/4", but then it runs into the propeller shaft. I am not really having trouble getting the transmission to disconnect from the engine - I just can't enough space to get the transmission free.

Thanks for your reply, anyway.

[longjonsilver]

Altho i can't help you with your particular problem, in my work in auto mechanics i have often thot that there was no solution. i have found that there always is a solution. Take a break, work on it later. There is no rush, is there? You WILL find a way to get the last bolt out
jon

[Sir_Crabs_A_Lot]

To get the shaft to move, you may have to put her on the hard and rig a couple 4"x4" fenceposts against the shaft log in an "A" configuration. Then use a come-along to drag it out. Just make D*MN sure there are NO things bolted to it first, like thrust bearings, zinc collars, flanges, etc.
Good Luck!

[Scubaseas]

Have any anti fouling paint on the shaft? If so remove it by sanding or by file. Maybe you are hanging up in the cutless bearing? Is the shaft bent?

[Scrimshaw4]

Do you have a pillow bearing on the shaft between the transmission and shaft log? If so you have to loosen its set screws. Have you loosened your packing nut / shaft seal? I had to use a slide hammer to back mine out so I could change my cutlass bearing. Just some thoughts.

[datapete568b]

Do you know if the 2 yards that remove the transmission in the past loosen the rear tranny mounts and raise the tranny up out of the way of the shaft coupler we need to do this to remove our transmission
Pictures would help
We use the tripod to lift the rear of the motor after loosening the front motor mount and removing the rear motor mount top nuts
If you do not touch the leveling not you will have no problem resetting the motor in place
We also used a crowbar and a block of wood to push the shift aft
Send some pictures it may Help with an idea

[Mike Banks]

Maybe there is a thrust bearing you have not noticed.

First rule of engineering--never force anything. If your propeller shaft will not slide back, there is a mechanical reason for it--you just have not yet discovered it.

Undo and remove the CV coupling if it has one. The thrust bearing will be bolted to a cross-member behind it.

[seabreez]

Originally Posted by CaptFrankM

I have run out of good ideas to get something (the transmission or the shaft) to move and am beginning to consider really stupid things. Before I do anything that I will end up regretting, I figured I would see if anyone had any ideas that I have not thought of yet.

Thanks.

That engine is not that heavy... you can loosen all motor mounts without playing with the adjustments for shaft alignment and then you can lift the rear of the engine until you have enough clearance... done that before...

[boden36]

If it has been done before, maybe go back to those who did it for some advice.


Regards,
Richard

[svninkasi]

Ive seen some creative rigging done ,

Rig up something around the rudder and block and pulley from that to the prop. Then run the line to a winch and pull it back.

[Scubaseas]

First rule of engineering--never force anything. If your propeller shaft will not slide back, there is a mechanical reason for it--you just have not yet discovered it.


X2. Finesse, not Force on anything moving/rotating and needing to be straight.

[CaptFrankM]

Thanks all for your input. I have gotten the shaft back about six inches, which should be more than enough to clear the tranny.

For those curious, I used a ratcheting tie down strap from Ace Hardware with a 1,000# WLL and a sixteen foot length. I went from the prop, around the rudder and back to the prop. I cleaned the shaft as clean as possible using open weave sanding tape. Then, I started ratcheting the strap in.

At first, I thought it wasn't working because the strap kept slipping. But then, I realized that the strap was slipping because the shaft was moving.

As an unexpected bonus, I had broken the prop free of the shaft and was able to remove it and bring it to the surface for cleaning and inspection.

All of this was done under the boat in about 8 -10 feet of water, using a Sea Breathe electric powered snorkel.

Once again, thanks for all the input. Now all I have to do is the rest of the job!

[Sir_Crabs_A_Lot]

Originally Posted by svninkasi

Ive seen some creative rigging done ,

Rig up something around the rudder and block and pulley from that to the prop. Then run the line to a winch and pull it back.

No,no, NO! NEVER attach anything to the rudder, most are not built to take the strain of a winch or such.