Would blackstone oil analysis tell me if used gear oil was yellow metal safe?

[victorforge]

I'm going to replace the gear oil in the transmission/transfer case on my dad's '63 CJ5. No one knows when it was changed since it was originally my grandfather's. To give you an idea, the differential oil was black. It doesn't see much use and only drives around the farm. I noticed driving it that it's impossible to downshift. It clicked when researching that the brass synchronizer is likely worn out, possibly from a non yellow metal safe gear oil being used. I have no idea how the fluid looks. I ordered VP classic 80w90 GL4 for the transmission change and Mobil 80w90 GL5 for the differentials. Would Blackstone be able to tell me if the previous oil was yellow metal safe?

 

[bullwinkle]

If it wasn’t there would be high sulfur numbers & a high amount of brass component elements (copper & zinc) in the UOA.

 

[kschachn]

If it wasn’t there would be high sulfur numbers & a high amount of brass component elements (copper & zinc) in the UOA.

High sulfur numbers?

 

[berniedd]

High sulfur numbers?

Maybe he means if higher sulfur concentrations in the UOA are found, then it's likely GL5 oil was used and not GL4.

 

[kschachn]

Maybe he means if higher sulfur concentrations in the UOA are found, then it's likely GL5 oil was used and not GL4.

I just haven’t seen a spectrographic analysis that includes that element.

 

[hrv]

I'm going to replace the gear oil in the transmission/transfer case on my dad's '63 CJ5. No one knows when it was changed since it was originally my grandfather's. To give you an idea, the differential oil was black. It doesn't see much use and only drives around the farm. I noticed driving it that it's impossible to downshift. It clicked when researching that the brass synchronizer is likely worn out, possibly from a non yellow metal safe gear oil being used. I have no idea how the fluid looks. I ordered VP classic 80w90 GL4 for the transmission change and Mobil 80w90 GL5 for the differentials. Would Blackstone be able to tell me if the previous oil was yellow metal safe?

Give them a call...

 

[BigCahuna]

I've read in a few places they recommend a gl-5 if there are no yellow in the trans, and to use gl-4, if there is. Way back in the day I had a '61 Willys Jeep pickup that didn't have syncos in the trans. That thing had to be shifted just at the right RPM ,or you won't get it in gear. I would try to find a service manual for your Jeep to see what they called for back in the day. Unless the oil has been changed recently, I'm not sure they could tell you what that oil was if it's original.,,