[T2] link to Amsoil ASTM-D130 tests of gear oils safe for yellow metal synchros

[Robert Mann]

>foamy oil came out over nosecone, likely from vent hole? ...
> Could it be water in this fairly new oil?

     I don't know any agent other than water that can cause foamy oil.  It
is familiar in crankcase oil after a head gasket lets water in from a
coolant jacket in a *late* Brasilian bus.  Also it occurs early in one's
development of water-injection; it is possible to suck in too much water
which immediately causes foam.
     Can water have gained ingress during your bus's long rest?

RM

On Tue, Nov 22, 2016 at 9:49 AM, MUTS <muts at verizon.net> wrote:

> http://xlforum.net/vbportal/forums/showthread.php?t=1533539
>
> Add to list: NAPA 80-90 GL3-4 oil, part #75-210
> Sta-lube 85-90 Gl4 gear oil part # SL24239
>
>
> I have an 091 trans in a 75 bus that was likely changed to a valvoline gl5
> gear oil only a few thousand miles ago, but has sat when the was losing
> power (due to slipping clutch, changed a year ago, but then was leaking
> oil, then changed trans shaft and crank seals last month and on warmup (no
> axles attached yet) the engine oil leak is gone, but oil was seen to leak
> gear oil from above nosecone- lost over a cup- stopped engine, cleaned it
> up, ran it again to see start of leak and no more leak!   Oil filler plug
> showed level was below fill hole. Next day did same- warmup, foamy oil came
> out over nosecone, likely from vent hole? Stopping engine, cleaning it and
> running again- no more leak! Now pulled fill plug, level is at least an
> inch below hole, and finger came out with foamy oil on it.  Drained all the
> oil, looks clean, magnet showed one tiny sliver.  Could it be water in this
> fairly new oil? Based on local sources, will use the NAPA $5 a qt gl3-4 oil.
>
>    What I do not understand is the dual nature of my 091 trans- has a
> hypoid Ring & Pinion, but yellow metal in the synchros?
>
> These synchros  will be damaged by the 2x level of sulfur found in Gl-5 vs
> GL-4 gear oil made to protect modern manual hypoid gearboxes?  This level
> will prematurely eat the synchros and not let them grab.
>
> The amsoil test lists GL5 brands that pass the test as safe for yellow
> metal.
>
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