replace damper ... or not??

[tmh]

We recently had our transmission go out on the way back from the Bahamas. Reverse works but forward does not. Fluid is new/fresh and up the the marks on the dipstix. So we sailed back to Pensacola, which is what sailors do!
I have a Hurst ZF 15 MA transmission and have ordered a new one.
Many of my fellow sailors on the dock say replace the damper while 'you are there'.
My mechanic says it is much more time consuming (i.e. more $$$) and asks if I would be willing to just do the transmission and leave the damper alone.
I would appreciate any advice from others who have been here before.
I have 2,400 hours on both transmission and damper that are original [2004]

Mike
#227 - Irish Ayes

[JohnNorton]

Mike: A great many posts/ discussions cover this topic pretty thoroughly. So many owners found the problem was in the damper plate, not the transmission. I'd read all you can before investing in a new transmission.

[tmh]

John,
Thank you.
So would a faulty/worn out damper prevent it going forward but still allow reverse?

Mike

[wolfe10]

No idea what your mechanic is talking about. Would LOVE to hear his explanation of all the extra labor!

Once transmission is out, replacing the dampener is very simple and quick.

Below is the procedure I used for replacing the dampener. Items 1-9 and 13-20 are the same for just transmission replacement or dampener replacement. Only 10-12 are "extra".

Damper Plate Replacement Procedure


1. Remove exhaust hose from muffler then from exhaust elbow and set aside. Dry water from shaft sump. Loosen/unscrew any connections that would be harmed by raising aft end of engine 5” fuel hose tie on ours. Remove small transverse filler piece forward end of aft berth to give more working room.
2. Make alignment marks on transmission output flange and on prop shaft flange.
3. Break loose the transmission to engine bolts, but do not remove.
4. Using 17 mm wrench, remove four bolts connecting transmission output flange and prop shaft flange.
5. Disconnect transmission shift linkage bracket and lay on engine compartment floor.
6. Using 15/16-inch or 24mm wrench/socket, remove nuts & washers from rear motor mounts.
7. Remove some of the engine compartment air exhaust hose and blower and push aside.
8. Using two 6-inch long 3/8-inch diameter carriage bolt with nut and fender washers sitting on top of small pieces of plywood to protect stringers, raise engine rear to gain sufficient clearance to remove transmission. This means the transmission and prop shaft flanges will barely pass each other when the transmission is pulled back from the bell housing. No need to loosen front engine mounts. The bolt was put through hole in the engine mount flange behind the hole the mount bolt goes through.
9. Remove six bolts holding transmission to bell housing then pry transmission loose using screwdriver at partially unscrewed bolts. Note that two bottom port bolts must be removed/inserted before transmission is fully splined up. Otherwise there is not sufficient clearance to insert later.
10. Using 3/16-inch allen wrench, remove five cap screws holding damper plate in place and remove damper. This requires turning over engine because only one or two screws can be accessed at any given engine rotation position. Note engine rotation is clockwise looking at engine from front. 15/16”crankshaft nut.
11. Clean bell housing and engine compartment

12. Install new damper plate using five set screws requiring 3/16-inch allen wrench. Use Locktite Medium Strength Blue which says allows for disassembly or adjustment with normal hand tools. Torque to: 100 INCH LBS.
13. Drain, flush and fill transmission.
14. Install transmission using six bolts with lock washers and 17 mm wrench. . Put Permatex Anti-Seize lubricant on transmission shaft splines before inserting into damper plate. Note that two bottom port bolts must be inserted before transmission is fully splined up.
15. Lower engine rear and, while doing so, simply push (or on starboard side, pull with string from the front of the engine) motor mount vertical bolts forward to line up with brackets on engine.
16. Install shift linkage using two bolts with washers and ½-inch wrench. Grease snap-on connector.
17. Install motor mount nuts and washers using 15/16-inch wrench. Also torque mount to stringer bolts
18. Check shaft alignment with .002 feeler gauge. Connect transmission output flange to prop shaft flange with four bolts with nuts and washers to front. Use 17 mm wrenches tighten bolts.
19. Install exhaust hose using two SS hose clamps each end.

20. Check transmission fluid level.