D6B Finals Lubrication Options

Folks,
I am looking for insight around the proper gear oil selection for the finals a D6B.

The dozer was recently purchased with little history on when the oils were last changed throughout the different components (i.e. engine, transmission, finals, etc.). My plan is to systematically attend to replacing the lubrication for each of these components.

I am starting with the finals and have been reading conflicting information on this site that I hope folks can clear up and finally provide a definitive recommendation.

My questions are:

1. Can I indeed use the modern 80w-90 GL-5 gear oil in the finals or not? Will the new oils deteriorate the bronze parts? Is there any bronze to worry about in the finals?

2. If I cannot use a GL-5 gear oil, do I look at GL-1 or GL-4? If I must, where can I get a GL-4 that is in the $60 per 5-gallon range, where I can find the GL-5 oils?

3. What are the brands of oils people are using and where are you getting them?

Thank you—I look forward to being part of this community as begin to work with and maintain my ‘new’ D6B—so I can start pushing some dirt with it!

Also—if you folks know of good mechanic to do onsite work in the Bonners Ferry/Sandpoint area, I am looking for a reference for those things that I cannot do myself (e.g. new cone seals on the finals, etc.).

Thank you

-Rolf

i suggest you first drain and flush the finals with diesel then refill. in your situation as you learn more about your tractor just get cat oil for the finals and transmission. i would stay with the type GL4 with proper visc for temps.

I use 85-90w GL-5 oil in all my old cats finals, been using for 20 years or more ,no problems. This doesn't make it right but it seems to work for me.

Bursitis, thank you for the guidance. It was my plan to execute your suggestion--it makes sense to get the years of sludge out and check for the quantity of metal bits before I put new gear oil in.

I am still deciding on the gear oil selection--again, still getting mixed suggestions. I am hoping for more conversation around this old topic.

Thanks again

-Rolf

Ah--oil questions again--you will get many many opinions! here is mine for whats it worth--I have used 85-90 Gl5 in all of my old machines in the transmission and final drives. a couple of my newer machines call for SAE 50 motor oil in the finals--look in your maintenance manual for guidance