Pinion Gear Carnage

[Ryan00TJ]

Background......

Built a new Alpha 1 over the winter. Used GLM lower gears and HD 1.50 upper gears. Shimmed per the FSM and it's set up right. Ran great all summer and gears were broken in per GLM instructions. At 82 hours on drive I noticed gear oil resevoir bottle offcolor. I pulled drive and found water contamination. I replaced all seals and fixed problem. I then totally pulled drive apart and cleaned all parts along with case. Gears were fine at this point. Reassembled and refilled with oil and went back to boating.

A few days ago, 125 hours on drive. I pulled the boat and drained the lower unit oil and the magnet was covered with metal. I pulled the drive apart and found everything ok except the pinion gear teeth have started to come apart and scall as you can see in the pics. All pinion teeth except three are like this. The F gear and R gear are ok. Upper gears are ok.

Did the water mixing with the oil hurt the gear and then it started to wear? Anyone have any ideas or similar experiences? I use Mobil 1 Syn 75W-90 and change it religiously at 25hr intervals. Drive shower on drive.
355ci 400hp SBC


I have a spare Alpha 1 with HD upper gears also so I threw it on so I can still enjoy these late Sept 80* boating weekends.

I plan to replace the lower gears over the winter with a new set of Merc gears and will redo the bearings as they got some metal pushed thru them.

[Panther]

Almost looks like the gear wasn't properly hardened. I'd have to see what the other two gears look like, that's not many hours... Setting the pinion depth is the most important part of setting up the Alpha lower.

I've seen a lot of alphas go thru worse and they were fine.

How much power?

[MOBILEMERCMAN]

It's hard to see with the picture. But a couple things come to mind, I don't think the mobile one is designed to tolerate water, Merc syn is a better choice and what do the odd three teeth look like. Can you take some more pictures maybe a straight on shot? Did the gears show any water marks at 82 hours?
Jim

[Panther]

Originally Posted by MOBILEMERCMAN

It's hard to see with the picture. But a couple things come to mind, I don't think the mobile one is designed to tolerate water, Merc syn is a better choice and what do the odd three teeth look like. Can you take some more pictures maybe a straight on shot? Did the gears show any water marks at 82 hours?
Jim

Jim, good point on the Mobil 1, I didn't think of that!!!

Have you tried the Amsoil Marine Gear Lube yet? It's designed to mix with water.

[Ryan00TJ]

I'll take some better pics of the pinion. Engine made 426hp thru dyno headers. With the marine manifolds probably 400+ or -. The three undamaged teeth showed a good wear pattern with no scalling like the others. I did not notice anything out of the ordinary at the 82 hr mark when the water contamination took place.

I've been using the M1 for 5 years or so now and previous drive internals looked great but this is the first time water has even leaked in and mixed with the oil. When I drained the oil the water and oil was not seperate. It was a milky cloudy yellow mess. I plan on switching back the Merc Syn or the Amsoil. I'm also going to use new Merc gears to replace these to take any quality issues out of the equation.

Thanks guys!!

[JIMG]

I've seen problems w/ GLM gears. Use OEM and you will have a longer life expectency.