I used Mobil One Gear Lube (75-90w?) in my Alpha (behind a 350hp 454) and stored it last season then ran it a total of 3 hours and the fluid is black. Looks as though there is no water in it but I am truly puzzled why the synthetic would turn black. I have not run over 4200 rpm as I am still breaking in the motor. Do I stick with the Mobil One or change to Mercruiser or Redline? I am heating the Alpha so bad that I need a drive shower? I am running in 60 degree water right now.....
Thanks,
Ken

Redline or Amsoil for the gearcase/upper drive!!! What did Merc ever do that put 350 HP into an alpha??? A good synthetic for sure + a drive shower and smart driving or you will break it. --- Jer

I rebuilt a 330 last year and upgraded the cam (ultradyne), cubes (.060" over), and compression..... (9.5-1)....350 is my best guess...I'll be driving real gently as I am laid off and only have until mid July to do my boating

ken
the temperature required to break down mobile 1 gear oil would not happen in your alpha. i would guess contaminents. you may want to check for leaks. if no leaks, the clutches. good luck.
Fran

If so what should I use to flush the internals f the drive out with???
Ken

Clutches in an Alpha??!? If there is no evidence of metelflake in the old oil I would just drain thoroughly over a 24 hr. period in a warm invironment and refill with Redline or Amsoil Race 75/90. --- Jer

jpclear
yep, i should probably have used a term other than clutch in an alpha to avoid confusion since it doesn't have the type cluthes a bravo has. it has a cluth dog instead. how about, the place where the metal to metal contact takes place when an alpha bangs into gear?

Your Mobil 1 gear lube may have already flushed the drive and thats why it turned black

Ive never had a problem with Mobil1 but I would throw a load of inexpensive gear lube through it and let it run on the hose for awhile then drain again and refill with whatever you chose to go with. I saw Penzoil has a synthetic drive lube at Walmart. Does anyone know anything about it ?

jpclear..........actually Searay had them on the 32Pachangas. They were painted white. They also painted the BBC's a different color. (I forget what they called them)