Do I have this right. GL5 yellow metal.

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expat

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Just for clarity.
I have a Diff in a RWD car that has Yellow metal thrust washers. The original spec is for GL4 which is a little difficult to come by.

My understanding is: GL4 is largely considered obsolete and for 'Rear ends' GL5 is now the norm.
However, GL5 may incorporate twice the sulphur EP additive of GL4 which may cause problems with yellow metal components.
But this has not too much an issue, as yellow metal is now seldom used in modern rear ends.

Some GL5's may have Buffers to counter the effects on yellow metal. But there is no requirement within the GL specification for this. ie. It is up to the manufacturer, and their 'word' it is yellow metal safe.
 
Yellow metal is a phosphor coating that increases rust resistance. Not as good as galvanizing but better than bare metal.

Not sure what is in it that makes it not yellow safe though. Must have a reaction with the phosphor coating.
 
Originally Posted By: spk2000
Yellow metal is a phosphor coating that increases rust resistance. Not as good as galvanizing but better than bare metal.

Not sure what is in it that makes it not yellow safe though. Must have a reaction with the phosphor coating.


I understand yellow metal to be those that contain copper and have a yellow color. Brass and bronze are two common types. http://www.machinerylubrication.com/Read/28958/ep-additives-effects

expat, I share your thoughts about the ambiguity of all of this. GL4 can be found if one cares to.
 
I think it's not really a concern. How many vehicles out there with the wrong fluid. I don't ever hear of any problems associated with it. skipping a fluid change probably does more damage. Just my opinion though and not one with any proof
smile.gif
 
mobil unofficially steer you to automatic or engine oil (refer to your car manual)so if you use their delvac atf sanctionned by allison test tes 295
You shouldnt have yellow metal problem (this test is a 300hour test all along allison will cause all kind of mayhem to mke yellow metal behave in unwanted ways. If an oil has a tes295 allison number? Dont sweat it. Its hard earned.but remember if you need gl-5 look for a sae j2360 oil.they dont cover the same market.mobil simplified yellow metal with atf non yellow metal with gear oil
 
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Originally Posted By: abycat
I think it's not really a concern. How many vehicles out there with the wrong fluid. I don't ever hear of any problems associated with it. skipping a fluid change probably does more damage. Just my opinion though and not one with any proof
smile.gif



I'm pretty sure I suffered from the use of the wrong oil a few years back.

I was restoring a Triumph that was in good running order, and I just wanted to change the Diff oil.
On this car,there was no drain plug, so I pulled the diff, split the case, drilled and fitted a drain plug and re-filled with GL5 not knowing any better.

During the course of the next 5 years the diff developed a clunck between drive and over run. It got so bad I drained the diff. The gear oil came out Green.
On inspection the planetary gear thrust washers that are a copper alloy, had disappeared, except for a few nuggets left in the diff case.
 
Originally Posted By: beanoil
Interesting blurb on GL4 here.. GL4/5 differences
I think if your spec is GL4, stay with it. You've only got a few choices though.


That link was written by Richard Widman, he often posts on this site.
The article was written for a Corvair forum and mainly adresses the un-suitablity of GL5 (even if Buffered, if I read it correctly) in Synchromesh transmissions. To me, he also seems to say that buffered GL5 'could' be used in place of (specified) to GL4 in non transaxle differentials. (as I have)

Maybee I'm a little slow here, but it seems unclear.
 
Originally Posted By: expat
Originally Posted By: abycat
I think it's not really a concern. How many vehicles out there with the wrong fluid. I don't ever hear of any problems associated with it. skipping a fluid change probably does more damage. Just my opinion though and not one with any proof
smile.gif



I'm pretty sure I suffered from the use of the wrong oil a few years back.

I was restoring a Triumph that was in good running order, and I just wanted to change the Diff oil.
On this car,there was no drain plug, so I pulled the diff, split the case, drilled and fitted a drain plug and re-filled with GL5 not knowing any better.

During the course of the next 5 years the diff developed a clunck between drive and over run. It got so bad I drained the diff. The gear oil came out Green.
On inspection the planetary gear thrust washers that are a copper alloy, had disappeared, except for a few nuggets left in the diff case.



Could this be a case of excessive clearances within planetary were not restored then?
 
On rebuilding the diff, the only worn parts were the yellow metal thrust washers.
But all the bearings were replaced because of all the thrust bearing bits passing through them.

There was no noise from the rear end before I changed the oil, and then the sound developed over some years.
 
no official cred! why you think i use mobil delvac1 in engine ? because it has the creds .its like me saying to you : dude i tell you trust me if you put this can of coconut oil in your application you will be trilled by you car behavior!you would be like ? where is the proff ? do you have allison number ? or something else official? your word? sorry lawyer dont care too much about those sadly
 
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Originally Posted By: yvon_la
no official cred! why you think i use mobil delvac1 in engine ? because it has the creds .its like me saying to you : dude i tell you trust me if you put this can of coconut oil in your application you will be trilled by you car behavior!you would be like ? where is the proff ? do you have allison number ? or something else official? your word? sorry lawyer dont care too much about those sadly


Can I get that in English and with punctuation? I'm too tired to sort that mess.
 
Originally Posted By: Joshua_Skinner
Originally Posted By: yvon_la
no official cred! why you think i use mobil delvac1 in engine ? because it has the creds .its like me saying to you : dude i tell you trust me if you put this can of coconut oil in your application you will be trilled by you car behavior!you would be like ? where is the proff ? do you have allison number ? or something else official? your word? sorry lawyer dont care too much about those sadly


Can I get that in English and with punctuation? I'm too tired to sort that mess.


Give the guy a break, he is from Quebe!
 
Originally Posted By: Joshua_Skinner
Answering my own question: "MTL, MT-85 & MT-90 are not for use in differentials with hypoid gears"

Look at the Red Line 75W90 NS GL-5 Gear Oil. "Improved copper corrosion protection to prolong synchro life"
http://www.redlineoil.com/product.aspx?pid=47&pcid=7


I'm not sure "Improved copper corrosion protection" really cuts it.

To me it kind of suggests:
It won't eat away your copper alloy parts as quickly as the old stuff!
 
+1

I'm not sure "Improved copper corrosion protection" really cuts it.

ya the better question is ,can it pass the tes-295 yellow metal corrosion test ( even if only unofficially)
 
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