Inconsistent shifting into forward gear

[Kyle Ewing]

I have a 1990 (hull #1010) with almost 1300 hours on the M25XP and Hurth transmission that doesn't consistently shift into forward gear.

Recently we motored or motor sailed most of the 300+ miles back from Mackinac Island, including 15 hours straight from Grand Haven to Chicago.  The only transmission problem was occasionally when cold it would hesitate for a few seconds before engaging in forward gear.  This never happened when warm.

The morning after the 15 hour motor we went out and it took a few tries to engage forward gear.  This past weekend the same thing.  At dock I adjusted the shifter linkage and changed the transmission fluid twice.  Before changing the fluid was a dull red and at the proper level. 

Symptoms:
•   Reverse always works.
•   About half the time the engine doesn't fully engage in forward.  When it partially engages the prop spins and moves the boat at only 1-2 knots regardless of engine speed.
•   To engage in forward I bring the engine back to idle then reapply power.  I don't have to touch the shift lever.

I have some decision points I'd like your input on:
•   When to address-- Do the symptoms indicate a major failure is imminent or gradual decline in reliability?  I know sooner is better.
•   Do myself or hire out.  I know the entire engine will have to move forward into the galley to service the transmission.  I'm confident I can do it, especially after replacing engine mounts last year, but may have to have it done due to time.  I figure two days of my time, day 1 removing the engine and transmission.  Day 2 reinstalling and aligning.
•   Repair or replace—Do the symptoms indicate a new/rebuilt transmission is needed or is there a serviceable part that will return reliability?  Could it still be a cable issue?  Any miracle cures?  I understand the damper plate should be replaced regardless.
•   If I replace the transmission, rebuild or go with a ZS 6 or ZS 10?

What is happening inside the transmission to cause this, a slipping clutch, bad springs or bearings preventing it from engaging, or something else?

Thanks in advance for your ideas!

[prh77]

Just helped a friend with the same problem....fwd clutch was shot. Think about it....you spend all of your time in foward gear. Mack Boring did the rebuild for $800 with a 1 yr warranty. Same symptoms, cloudy fliud, PO never changed it.

[prh77]

And yes, we did the damper plate, $120 compared to $ 300 FROM UNIVERSAL. Same MFG, do some research on this site.

[prh77]

Looking at your post one more time.....yes, check the cable rigging, disconnect at xmission and shift by hand at shift lever. Make sure you are all the way in gear, if tranny still slips, time for plan B.

[Ron Hill]

Kyle : I'm going to guess that you have a Edson stainless shifter and that your shifting lever does not have enough throw to get it completely in gear.

You have slipping clutch plates in FWD.
 
With a cold transmission disconnect the shifter cable at the transmission. Then start the engine and hand shift the transmission lever into fwd (move it aft!).  If there is no slippage and it goes into fwd gear smartly, then you've got an adjustment problem.  Drop the shifter cable attachment into the bottom hole on the shifteing lever on the transmission (you might even have to lengthen the shift cable?)

If you decide on a new transmission I'd go for the ZF10 and NOT the 6.  If you have to remove and replace the transmission I have a almost new M25XP damper plate (less than 100 hrs) I'll sell for $75. 

Good luck

[Kyle Ewing]

Thanks all for advice.  Finally got around to disconnecting the linkage and unfortunately symptoms remain the same.  I'm starting my search for a new transmission.  Advice for a source would be appreciated.

Kyle

[Dave DeAre]

Kyle,
ZF transmissions are available at a good price from Harbor Marine in Evertt , WA. Google Harbor Marine.
They apparently also sell new transmissions on Ebay as Hotrodspee

Google ZF-10 transmission

Good luck!

[Kyle Ewing]

I have a new ZF10M and damper plate from Harbor Marine and will install it this weekend!   

When disconnecting the exhaust before pulling the engine, will I have to remove the exhaust riser or just disconnect from the muffler and work the engine out with it attached?  I want to have a spare exhaust flange gasket on hand if the exhaust has to come off.

[Stu Jackson]

Kyle, you'll need to disconnect the riser from the manifold, not the muffler.  The riser could actually stay in place and leave it connected to the muffler.  It should be easily moved aside to be able to clear the engine.  Buy two green gaskets, they're all of $5 apiece, 'cuz the stud holes are very, very close to the edge of the gaskets and need to be installed very, very carefully.  If you blow one, you'll have another right at hand.

[Ron Hill]

Kyle : If you are just going to lift the rear of the engine to remove the bell housing with the transmission - just disconnect the exhaust at the muffler.  Also you can leave everything connected except the main negative ground wire(attached to the bell housing).

That's what I did when I replaced my rear engine mounts.  A thought

[Kyle Ewing]

Ron--Interesting idea about only raising the back of the engine.  I stared at it for awhile and couldn't figure out how to get the bell housing off with the clearance I have.  I have grand plans to clean the engine, replace hoses, etc. While apart.

Stu, thanks for confirming what I feared--I dislike taking the exhaust flange off. 

I'll take pictures and let everyone know how it goes!

[Ron Hill]

Kyle : The only reason that I mentioned rasing the rear of the engine is that it's a "hell of alot of work" to remove and replace the engine. 

I've done it with the old engine 3 out and 2 back in, not including the installation of the new engine. Did 98% of the work myself!!  A thought

[Kyle Ewing]

The replacement went well.  The steps at http://c34.org/bbs/index.php/topic,293.0.html were generally accurate.  Total time was about 11 hours.  I was suspicious when I didn't have to burp the engine after draining coolant to remove exhaust flange and replace some hoses, but engine warmed to 160 and stayed there for 20+ minutes of motoring at 2500 rpm.

The only surprise was not expecting split washers on the damper plate screws.  We made a trip to the store for new ones as the originals came out flat.

Special thanks to all the contributors on this board!  Again you've given me the confidence to complete a challenging project.  I took pictures and plan a detailed write-up.

[kable]

" I took pictures and plan a detailed write-up"

How is the detailed write-up coming along? ;>)
I think I have a dead transmission and probably need a rebuild or new.
I can't do it myself but would like to learn/share w/ a mechanic I find.

-kable

[Kyle Ewing]

Here are pics.  This would have been a good blog entry but I didn't turn out to be the proficient blogger I thought I would...

Tranny is still working well ten years later.  I change fluid every fall and periodically check for discoloration and it's always pink with no noticeable discoloration.