1999 Freightliner FL70, 70k mi, Shell Dentax S50

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George7941

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FL70TrannySept08.jpg



I will be replacing the oil with a fresh batch of Dentax S.

I have a related thread here https://bobistheoilguy.com/forums/threads/foam-in-transmission-oil.93581/


Is 174ppm of iron an 'urgent' level for gear oil? After all, there is no oil filter. Truck is driven by various drivers and I expect the iron is from the synchromesh dogs clashing.

Only Aluminium I know of is the gear case itself, there are no moving parts involving aluminium. So, why do I have 156 ppm of Al?
 
Hi,
George7941 - I sometimes have difficulty with the Lab Tech's informations on UOAs - especially in transmissions and axles!
Sometimes even the Blackstone UOAs on petrol engine outcomes contain comments that are simply misleading and/or downright wrong!!

In MY judgement the wear metal levels in this "Mid Range" FS Eaton axle set are not out of order at all and do NOT call for an urgent OC. I would continue to run the lubricant and further monitor the aluminium uptake rate

If the lubricant has been changed I would then monitor the aluminium uptake rate after about 30k

I suspect that the aluminium uptake rate is a feature of the particular metallurgy used in this axle set

The levels of other items are within bounds as defined by Eaton

Shell's Dentax is a top level axle lubricant!
 
We see UOAs from motorcycles that share engine oil with the tranny reach 50+ ppm of iron (and elevated aluminum as well) and that's considered normal.

The lab comments refer to an oil filter. Um, do they think they're looking at ENGINE oil?? I agree with Doug, the lab's comments are all-too-often far from the mark.

How many changes has this tranny seen? One? None?

I would think in a tranny this large and heavy duty, that gears rubbing on each other with such force would cause them to polish each other slowly over many tens of thousands of miles and produce this kind of wear ... and I wouldn't worry about it. If this oil has been changed a few times already and was in use 20,000 miles or less, I'd be worried.

I think in the other thread you said something like 65,000 miles? If this is factory fill or 2nd fill, I wouldn't worry about it too much.
 
I wonder why the lab did not do any viscosity tests.

At least now you know water did not cause the foaming.
 
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Did you tell them this oil sample was from a manual transmission?

If this was for 65K miles, it looks good.

But no TAN or viscosity reporting doesn't really tell us much about the final condition of the fluid itself.

I would contact Terry Dyson and send a sample to him and then have him give you a full report. He has an extensive database of analyses.
 
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Yeah, I told them it was from a tranny.

The 'Compartment' is listed as transmission in the Lab Report displayed in my post.

I expect that they would have tested for viscosity and TAN if I had paid for a level 2 analysis.
 
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