Gear/Transfer Case Oil - Should I change 12 year old oils with low miles driven?

Yesterday after reading the responses on gear oil for my 3rd gen Taco; I got to thinking about my 2004 Ram 3500. I changed the Gear/Transfer/Manual tranny oils at 10K miles. It has 32K miles on it now. So I know based on mile driven those fluids are still good.

I was curious what fluids I had put in and looked in my log book. It was Amsoil and Mobil 1. But what surprised me was that change was done all the way back in 2010. So 13 years ago. Did not realize it had been so many years - next year I will have had that truck for 20 years!

Should driveline fluids be replaced just due to the length of time they have been in there? Is there condensation issues that come into play?

 

It definitely won’t hurt it.
If you have the money to do it, you should.

I’ve seen some differentials go 20+ years and 100k+ miles with out being changed. But that’s bad, real bad in the gear set. Just change it every 5 years or 30k miles. You might push it to 50k if you don’t tow.

 

I have always changed diff fluids based on mileage. I'll check the levels, condition of fluid and just run it until around 40k or so.
Now, if those diffs are ever submerged in water, then everything changes.
As far as the transfer case fluid, I usually inspect the level and condition and I'll change around 35-40k or so.
And honestly, I cannot tell you how many people run their trucks up near 200k and have not done a thing to the factory fill.

 

I've seen differentials rebuilt at a buddies shop that had over 100k miles with no oil changes. All the bearings in them were tapioca. I believe the gear oil should be replaced every 30k miles.

 

When was the brake fluid changed?

 

I did the brakes and put new brake fluid in within the last few years. I will have to look in my log book.

 

Yeah, if the brake fluid looks discolored, time to replace it, as it's hygroscopic. I changed my brake fluid in my last toyota after 10 years...it became yellowish brown appearing.