automotive rear 90 wt oil in ocean pro gearcase

[crazy charlie]

I drained the gear lube in my 95 150 ocean pro in the fall and I didnt have time to get the proper gearlube to replace it with.I took some 80 or 90 weight automotive rear end lube that I had in my garage from a long time ago and filled the gearcase so it would not be empty for the winter.I am just getting around to changing it to the correct lube.I have no intention of leaving the automotive stuff in there but how bad would it be assuming that there are no leaks and the lower unit is in perfect condition??????

 

[Paul Moir]

Re: automotive rear 90 wt oil in ocean pro gearcase

As long as it's got the API GL-5 rating you have the right stuff to prevent wear & foaming. It just won't have the anti-corrosion additives and won't do well with water added.

 

[crazy charlie]

Re: automotive rear 90 wt oil in ocean pro gearcase

Thats kinda what I was figuring Paul.I got a few gallons of this stuff 20 years ago from a friend that worked at a Pontiac dealer.He pumped it out of what looked like a 20-30 gallon barrel.At the time I had an alpha drive that started leaking and I didnt have the money to have the boat hauled and repaired so I just added the fluid to the resovoir as needed.He said that" if its good enough for a Trans Am rear,its good enough for your boat".Fortunately I was ambitious the year before and added the resovoir to my boat.No plans on leaving it in the Ocean Pro,just curious.

 

[Texasmark]

Re: automotive rear 90 wt oil in ocean pro gearcase

Well, For all my life, OB motors used a "Hypoid" lower unit oil. Now what does Hypoid mean? I have no idea. I just checked in the "Webster's New Collegiate Dictionary" and it's not even listed.<br /><br />So a couple of months ago, I am in WW getting some goodies and run across a wall full of Pennzoil Marine Products. Lo and behold is a 100% synthetic marine gear lube that meets (exceeds) the requirements of all the big engine mfgr's and of all things is GL-5 rated, plus has some marine superlatives like low foaming and sticky additives so they say.<br /><br />Now who am I to question the integrity of Pennzoil. Not about to. They have earned our respect.<br /><br />Apparently the marine lower unit has 2 big problems.<br /><br />1. Water intrusion which means that the lube has to remain stuck to the metal to keep the water away.<br /><br />2. Bubbles (foaming) caused by a small gearcase with a small amount of lube running at a high rpm.<br /><br />So now what?<br /><br />I dunno.<br /><br />Best bet is to drain your auto stuff out before using and install the recommended fluid from your OEM...since they test these oils and should know what kind of results to expect.<br /><br />Now the Pennzoil Marine 100% syn GL-5 that I installed is staying till drain/change time. <br />I'm not draining it out, for now.....but when I do, I have some Merc premium to install. <br /><br />My 2c.<br /><br />Mark

 

[Paul Moir]

Re: automotive rear 90 wt oil in ocean pro gearcase

Hypoid refers to hypoid cut gears. Hypoid cut gears are like a bevel gears; they turn the direction of rotation 90 degrees. But if you ever heard an old truck with straight cut bevel gears you know the problem. They whine badly. The solution is to cut the teeth in a helix so that tooth engagement is smooth rather than abrupt like with a bevel gear. These are the kind of gears that you find in an outboard.<br />Now, with a car's rear differential there's good reasons to have the input shaft out of line with the two output shafts which lead to the wheels. This makes for a variation on the spiral gear, which is called a hypoid gear. The hypoid gear's teeth slide one against the other quite a bit as the gears rotate, so the thin oil film that prevents wear on the gear teeth is normally wiped away. So those type of gears need extreme pressure additives, which help hold the oil film to the gear's teeth when they slide, and as I understand it also have ingredients to help control the damage to the teeth if the oil film is wiped out.<br /><br />So for some reason, outboard manufacturers feel they need the EP additives in hypoid gear oil. I'm sure they've got good reasons, I just don't know what they are. The API GL-5 rating is for hypoid gears in high speed or high torque conditions. GL-4 is for automotive hypoid gears run at moderate loads. The modern outboard L/U lube specifications I've seen refer to GL-5. Some insist on synthetic and lower weights like 75.<br /><br />I'm sure the OilDoc can explain this stuff a lot better and probably a lot more accurately. But I find it interesting stuff. The EP additives are, I guess, sulpher and chlorine based which give hypoid gear lube that distinct stink. I've heard that in some situations it can be corrosive because of them.<br /><br />Gear type link with pictures:<br /> http://science.howstuffworks.com/gear4.htm

 

[seahorse5]

Re: automotive rear 90 wt oil in ocean pro gearcase

The lube called for in your Ocean Pro is not a hypoid 90 gear oil. Yamaha, Suzuki, and earlier Mercs used it, but Johnson and Evinrude use a semi-synthetic that is "thinner".<br /><br />Just drain it out and use the original Ultra HPF oil for best results.