Can oil analysis determine if the previously 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?

 

[sds911]

Call or email the lab. You might be able to tell by comparing the add pack of the UOA to the add pack of a gl5 VOA posted on the forum. But, my guess is it depends on how long your fill has been in the vehicle.

Definitely sounds like a synchro or other parts replacement or rebuild is likely. I had similar issues with the 911 and fluid changes did nothing to improve a known issue. After taking it to 4 different dealers was finally warrantied under CPO. And sure enough synchros were replaced.

 

[MolaKule]

@victorforge No $30 analysis can tell you that and I doubt BS could tell you since they don't have the needed instrumention.

I think the synchro's are worn out.

At the time grandpa put lube in there GL-5 gear oils were not safe for copper-alloy synchronizers. Today, they are.

A '63 tranny probably used a 90 grade so a modern synthetic 75W90 MTF with a GL-4 rating should suffice.

Here is a list of 75W90's:

1. Amsoil MTG
2. Redline MT-90
3. Castrol Syntrans Multivehicle 75W-90
4. Castrol Syntrans Transaxle 75w-90
5. Ford XT-75W90-QGT (Carries a GL-5 rating as well)
6. Ford MOTORCRAFT® Full Synthetic Manual Transmission FluidXT-M5-QS
7. ACDelco 10-4059 GL-4 75W-90 Manual Transmission Fluid
8. RAVENOL TSG SAE 75W-9
9. LIQUIMOLY 75W-90 GL4
10. PENNZOIL 75W90 GL-4
11. Motul MotylGEAR 300 GL-4/GL-5
12. HPL Manual Transmission Life 75W90 16.8 cSt

 

[ceecbtg]

Blackstone may be not, but you can do other analysis or laboratory with basic contaminants, additive package and cooper corrosion test. If this oil was even right one for your old gearbox, after 20-30 years could show really bad results and corrosion, but at least you can see interesting info.

Your actual oil selection seems ok to me (if car asks for these specs).

 

[Jetronic]

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?

If it wasn't there would be loads of copper in the analysis.

 

[victorforge]

I bought a 1953 M38A1 with the same transmission as that cj5 a few months ago. The previous owner had the trans professionally rebuilt by a mechanic I was familiar with. Well, I was checking the level since it's been leaking a little when its hot. Gear oil was full of brass particles. It could be either break-in related or not yellow metal safe. I'm emailing Blackstone to see if they can determine if it was yellow metal safe or not.

 

[tasch72]

The type and amount of sulfur in gear oil determines yellow metal compatibility. I have never seen a UOA identify sulfur content.

 

[Chris142]

If you are trying to downshift to first it likely won't. The early T-98,T-18 etc did not have a synchronized first gear anyway.

 

[victorforge]

If you are trying to downshift to first it likely won't. The early T-98,T-18 etc did not have a synchronized first gear anyway.

That I'm aware of. The cj5 downshifts fine to 2 and 3 now.