Gear case

[Dani1989]

Good day I was having problems with a big bang and couldn’t figure it out. So I changed the oil in the lower unit and had ALOT of shavings and a lot stuck to the screws. So I took the gear case apart and found that the clutch dog looks to have been the possible problem I just don’t see damage to the gear which I thought would also have damage. Would this be the reason ? And what is causing the clutch dog to do this. The forward is worse than reverse. But both show some damage.

 

[jimmbo]

I would the Gears are Shot, as there are several teeth with what look like Gouges and chipping, the Clutch Dog is worn, I suspect the Bearings are also going to show Galling. Most Common Reason for Lower Unit Damage, is people "Easing" it into Gear. Shifting needs to be very Quick with no Hesitation

 

[alldodge]

The dogs look like they have been shifted slowly for some time

The one gear has a mark in it but doesn't give me a worry of failure

Some of the metal may be coming from the upper

Is Merc gear lube being used?

 

[Scott Danforth]

the pinion is toast, the dog clutch is toast. with that much metal running around in the gear case, assume the bearings are toast.

 

[KJM]

the pinion is toast, the dog clutch is toast. with that much metal running around in the gear case, assume the bearings are toast.

Agree on the clutch dog and likely bearings, but do you really think the pinion looks that bad? The teeth aren't rounded off and I don't see how a few little dents in the mating surfaces would affect performance, but I'm not a mechanic.....

 

[Dani1989]

The dogs look like they have been shifted slowly for some time

The one gear has a mark in it but doesn't give me a worry of failure

Some of the metal may be coming from the upper

Is Merc gear lube being used?

Yes. When I changed the oil it came out clean. But this time around (maybe an hr of water time) it drained out black.

 

[Dani1989]

I would the Gears are Shot, as there are several teeth with what look like Gouges and chipping, the Clutch Dog is worn, I suspect the Bearings are also going to show Galling. Most Common Reason for Lower Unit Damage, is people "Easing" it into Gear. Shifting needs to be very Quick with no Hesitation

I didn't know about the quick shift as I'm a new boater. Thank you. Also can you help me with where the damage is on the gears when I inspected they looked fine and I don't see any gouges but this is all new to me. And which bearings are you talking about where would I find these so I can send pics and get help?

 

[Dani1989]

the pinion is toast, the dog clutch is toast. with that much metal running around in the gear case, assume the bearings are toast.

I think I'm gonna have to clean up the gears and pinion and repost pics because I'm having difficulty see what all you guys are seeing as gouging. Where would I find the bearings? All of this has happened within about an hr of running the boat. I had changed the lower unit oil and it was clean and then went on water for an hr and it just got to the point of grinding and not going into gear. Then I got home and changes oil and it was black.

 

[Dani1989]

Quick question after watching a video. Is there suppose to be a spring in this spot. Because there wasn't, and on a video I just watched a guy had a spring in there could be a cause of a diff motor size, but just another question. Thanks guys for all your help.

 

[Chris1956]

What brand, year and HP motor? SEI may make a brand new gearcase, for the price of replacing those gears, bearings and dog.

 

[Dani1989]

What brand, year and HP motor? SEI may make a brand new gearcase, for the price of replacing those gears, bearings and dog.

1989 90hp Johnson v4

 

[Chris1956]

OK, see if SEI makes one. I know they make replacements for my '98 Johnny V6. Pay attention the the driveshaft length. My '98 has the 2 piece driveshaft, and the SEI replacement reuses the upper driveshaft.

 

[alldodge]

First gear pic (middle one) between 1 and 2 o'clock is the mark I was referring to

 

[Dani1989]

First gear pic (middle one) between 1 and 2 o'clock is the mark I was referring to

I'll clean them up and resend pics. Sorry guys

 

[racerone]

No spring in there.-----Make sure shift rod is set at correct height on re-assembly.

 

[Dani1989]

No spring in there.-----Make sure shift rod is set at correct height on re-assembly.

Okay. Thank you. Do you happen to know why the gears and clutch dog would not fully be engaging? It seems like the clutch dog was just skimming the gear the way it is damaged.

 

[Dani1989]

New videos.

 

[Dani1989]

OK, see if SEI makes one. I know they make replacements for my '98 Johnny V6. Pay attention the the driveshaft length. My '98 has the 2 piece driveshaft, and the SEI replacement reuses the upper driveshaft.

I'll take a look. Thanks.

 

[racerone]

Shift rod height was likely not set.----A common mistake.

 

[Grub54891]

Clean to you and clean to me are two different things. You can wipe the dirt with a q-tip, its not clean. A little hard for me to see damage unless it's cleaned and dry. Brake clean and a wipe down isn't to hard.