The Stovebolt Site Forums The Shop Area Driveline Milky Gear Oil???

I needed to check my tranny oil level and much to my surprise I had milky gear oil. Since I just got it back from the shop and the put all new gaskets in it I would think they drained it and put new oil in. I know it was parked out in the rain for a while but the transmission was out while the rebuilt the motor. How else could my tranny oil get milky? Do they make a milky looking 90 weight oil?

Thanks in advance.

.. no milky looking 90 wt. that I know of or have seen.

I guess I need to call and ask if they even changed the tranny oil. Good thing I have a good spare 4 speed. I suspect the P/O left this truck out in the rain for 3 years with a bad windshield and the water just ran down the dash and into the shifter housing. No wonder my tranny is so dang loud. Although the shop did replace all the gaskets, or so they said.

Any suggestions on how to rinse it out?? Just swap the 90 and drive it, and repeat???

Drain it, and pour in 2 quarts of Diesel fuel and maybe a quart of 90 weight. Run the engine with the trans in neutral for 15 minutes or so and drain it. Virtually all the water contaminaztion should be gone, but the rust damage to the gears will still be there. Since water is heavier than gear oil, the cluster gear would have been partially submerged in water for a long time. The grease and water wouldn't have emulsified until you ran it awhile.
Jerry

I did what you suggested!! Thanks. Now I want to know if putting in 600 weight would be okay?? It was suggested that my tranny would quiet down. He even sold heavier grade gear oil. Any thoughts??

Thanks, Dan

600 weight? Is that a typo? Normal gear lube thickness is 90, and some of us use 85W-140 synthetic gear lube, but I've never heard of using anything that thick in a transmission! If gear noise is a problem, it might be wise to use an additive like Lucas oil stabilizer along with the gear lube, but I don't think extra-heavy lube is a good idea. For one thing, it consumes a lot of power just to stir up thick lube, and a stovebolt engine doesn't have enough extra power to deal with a lot of parasitic power drain!
Jerry

Jerry, No typo. The guys at Hagen Hiway auto parts had it on the shelf and swore by it. In fact he told me not to use 90 wt. Since I just put 40 dollars worth in my tranny I was a little gobsmacked. I'd never heard of anything that thick either. He even had 1200 wt.

I'll stick with the 90.

600W [not "weight"] is steam cylinder oil and is what was used for straight cut gearboxes back in the 20's and 30's, and some of the oldsters at ChevyTalk use it for their 20's cars [model A & T folks too]

Bill

OK- - - -now I know why Model T's had a habit of pulling forward when the engine was started in very cold weather even with the planetary transmission in neutral. It was not uncommon for one to trap someone against the front wall of his garage until the oil warmed up enough to push the car backwards after hand-cranking the engine. Smart drivers learned to jack up one rear wheel before cranking up a cold one.
Jerry

Sorry for asking but what is the difference between "w" and "weight"?

the name of the product is "600W", the W does not stand for "weight", which refers to the SAE viscosity rating, see here, or the link I posted above from Mobil [I believe Shell also has 600W] - also Penrite and Lubriplate make a 1200W that's called Steering Box Lube

Bill

At one time, "W" stood for "winter". For instance, a 20W-20 motor oil was tested for flow rate at 0 degrees C. (32F) and again at 100 degrees C. (212F). A 10W-30 oil has the same flow characteristics as a SAE 10 oil at the cold rating, and lubricates like a SAE 30 oil when hot. Its physical thickness DOES NOT change with temperature, only the lubricating capability.

85W-140 gear lube flows like SAE 85 oil when cold, and has the lubricating capability of SAE 140 when hot. Apparently, the "600W" does not follow the old SAE rating system, which involved timing the flow of oil through a fixed-size orfice at various tempertures. Faster-flowing oils got a lower numerical rating- - - -SAE 10 flows fast, 30 is slower, and 140 is VERY slow!
Jerry

Huh!!!!

So is the term 30 weight or 90 weight wrong? Is this something I made up?? Or is this a common misnomer?

yes, a common usage, and the single number ratings are referred to as "straight weight" [and the two-number ones are 'multigrade' ], but as Jerry points out, the 'W' really means winter, for the cold viscosity rating .... SAE oil standards are different now than when they started, about the 20's-30s, when they were classed as 'regular' premium' and 'super', and the 600W stuff under discussion pre-dates the SAE standards

Bill

600wt is about the same visc as the modern rated 160 gear oil, but it has no sulphur and plays well with water, and stupid high temperatures.


The T planetary trans, shares the engine oil, in most cases 30wt. 30wt is mighty thick when cold! In winter, I always used 10-30, but in the summer, it falls out too fast.

The rear end is where the 600wt goes. Or, like in my TT, it goes into the two aux trannies, and the worm drive rear end. I buy my pails of 600wt at the local Esso Bulk Plant.