gear oil 80w90 vs sae 90

[moemoe]

Can I use 80w90 in my bottom end oil? and what is the difference between the two, I ask because walmart has castrol 4L 80w90 jug on for 12.99, and I honestly do not know the difference between the 2. thanks moe

[lookinforwalleye]

Can I use 80w90 in my bottom end oil? and what is the difference between the two, I ask because walmart has castrol 4L 80w90 jug on for 12.99, and I honestly do not know the difference between the 2. thanks moe

 

I don`t know the difference either but use what the MFG. says to use in my case SAE90

[DanD]

I wouldn’t use automotive gear oil in the bottom end.

Here’s a short description of marine grade gear lube.

I’m not saying use Pennziol; it just happened to be what I found for a description.

 

Dan.

 

PRODUCT DESCRIPTION

PENNZOIL MARINE® OUTBOARD GEAR LUBE and PENNZOIL MARINE® HIGH VISCOSITY LOWER UNIT

GEAR LUBE are special marine grade formulations designed to withstand high amounts of water contamination. Both

contain stable extreme pressure additives and corrosion inhibitors to protect gears and bearings subject to corrosion by

water seepage. Special antifoam agents insure excellent lubrication to all gears and bearings under the severe churning

action of marine gear cases.

[cheaptackle]

Hopefully Bernie will chime in and let us all know if this is right - I believe the SAE90 has a lower operating temperature range application and the 80w90 a higher one (like in a diesel engine or other "heated" use"). The 80w90 would rely on the higher temperature to help in flowing whereas the straight 90 flows at lower temperature.

 

Michael

 

And Bernie says the anwser is....?

[OhioFisherman]

Don`t quote me on this but I believe the W denotes a winter grade of lubricant. As it get colder oil thickens and doesn`t flow as well until it warms up. The reason for mixed grade oils like 5w30-10w30 in automotive engines, flows like 5 weight, protects like 30? You don`t usually see boat motors operating in the extreme cold like car or truck engines though, and the gear case is usually submerged in water that is at least 32 degrees f or warmer. I would be leery of using something that isn`t manufacturer recommended?

 

It was a fairly common practice at some of the trucking companies I worked at to take a sample of the gear case oil (transmission) and send it to a lab for testing. Unusual amounts of metal particles in the oil could indicate a lubrication problem or abuse.

 

Most of my car engine experience is on small block chevy`s, older one. A the oil pump was driven by the distributor which was gear driven by the camshaft. A slot on the bottom of the distributor fit on the oil pump and drove it. I had always been told that most engine wear occurs on start up, the oil drains into the sump and a brief lag until oil pressure build and it starts flowing. A cold day and thick oil makes it harder to flow. Don`t race a cold engine, let the oil warm up so it can flow well.

 

I have never had a lower unit apart, just my guess that there is no pump, the gears are either submerged in oil or splash lubricated.

[Roy]

Paul is correct.

 

http://www.upmpg.com/tech_articles/motoroil_viscosity/

[hirk]

NEVER!! use anything but marine gearcase oil.The Penzoil blurb spells it out for you.

[Fisherman]

Hopefully Bernie will chime in and let us all know if this is right - I believe the SAE90 has a lower operating temperature range application and the 80w90 a higher one (like in a diesel engine or other "heated" use"). The 80w90 would rely on the higher temperature to help in flowing whereas the straight 90 flows at lower temperature.

 

Michael

 

And Bernie says the anwser is....?

Step away from the oilcan, the lower the number, the thinner the viscosity, ie, 80 flows easier than 90 at the same temperature

[Tybo]

No you can't use 80w90. this oil is made for open gear case. it will swell once you go over the operating temp for the oil.The lower unit is a closed gear case,sae90

has agents add to help prevent swelling from heat.

Marine grade has agents in it for if the oil leaks out. It break down faster in water..

[vinnimon]

Can I use 80w90 in my bottom end oil? and what is the difference between the two, I ask because walmart has castrol 4L 80w90 jug on for 12.99, and I honestly do not know the difference between the 2. thanks moe

no,use whats recommended by the manuf.80w90 or 75w90 syn is used in tranies, diffs and wheel end bearing esp on heavy trucks and trailers.I have thought about it as well since I can get for free to a degree.I use merc gear lube, a 1 ltr bottle $14.80.