In the early 1970`s Caterpillar changed it`s recommendation for the final drive oil in the D6c. They went from 140 weight oil to 50 weight oil. This a pretty big change in my view. Does anyone know why they made this change? Did they change for D5,7,8,9 too. Many moons ago when I did construction work full time our grease truck only had 10w, 30w and 90 weight. :beatsme
I never did change, Cat said the 50w would filter better in pump fed finals, I stayed with 80w-90w in the D8's I had. The trend has been for lighter lubes but it's hard to switch when you have history with a product. 140w seems heavy to me though.
Usually the bearings goes in the finals before the gears.The 50W lubs the bearings better then the heavy weight. If the bearing goes then the gear gets miss lined and takes a tooth off.So keeping the bearing in good shape is the key. I switched and have had good luck.If you have extreme temperature change it might be better to go higher or lower weight.Good luck:usa
I'm pretty sure it was when wet brakes appeared on the loaders. The discs were not compatible with gear oil so the spec was changed to transmission oil. I'm guessing the TTT oil spec was changed to standardise across the range. Also was there some question over seal compatibility with gear oil? I'm glad they did. Gear oil is terrible, stinky stuff.....
Final Drive Oil I'm reading the Lube and Maint instructions for the D6C 76A. Cat recommends Series 3 Crankcase Oil for the finals. Temp Range of -10F up recommends SAE 30. I have augmented each final with a gallon, or 20%, of motor honey. Either STP or Lucas. It really reduces noise and sticks with the bearings when the tractor sits for extended periods. The mechanic I have used for years said that the high sulfur gear oil and a little condensation will create a sulfuric acid problem within the final case and that etches the surface on the bearing cups which leads to their eventual failure. Once I started using this recipe I had very little trouble.
The old guys up in their 70's around here use that same recipe. They Get long life out of their finals.
Cat reccomends the TDTO-50 for the finals...whan I had mine worked on they put in 80-90 wt GL-5 Gear oil. I was a litte concerend since I've read that at least some of the GL-5 spec oils can cause corrosion on brass/bronze bearing materials. There's a lot of confusing info online about it so I don't know for sure if it's a real issue. (Are there are any bronze busings in the finals to worry about anyway?)
Those old oval track D6 machines dont have any brass inside. I really have not seen any horrible failures due to using 90 wt vs. 50 wt. and I have repaired alot of them in the last 15 years. My experience is if you keep good 50wt to 90wt oil in them and keep them full you will be ok.
Yair...we took delivery of our first D9's Cristmas Eve 1965 and the realy novel things for us (after many years of Allis Chalmers) was that they took thirty weight series three in all compartments, including the finals and they burnt black fuel instead of distillate.