Difference Between Rotella T1 40W and T 40W

Is there any difference between older Rotella T40W and newer T140W? Can I mix the two?

You can always mix the same viscosity oil. You can also mix with 30wt if in a pinch. Just don't put multi-weight oil in.

I would check the API tag first. If your a Detroit musher, CF-2 would be the ratting on both pails.
You should have no problems mixing them then.

Yep DDs.