is this just a spec? are does this have synthetic in it? need some for my trans in a 85-90W. I have read not to use a synthetic in the older 4-speeds any truth?
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Re: GL-5
Lyndon, GL-5 is an API specification for gear oil. It could be fossil or synthetic base or even a blend of the two. I would not hesitate to use synthetic if I was going to change the fluid. If you are just adding I would stay with standard oil. You would gain nothing by mixing the twoDick Whittington -
Re: GL-5
The GL-5 spec is called out for virtually all hypoid gear axles and is also called out for vintage manual transmissions.
Go to www.api.org "in your garage" to learn more about motor oil and gear oil specifications.
All "car guys" should understand them and there's nothing complicated about it.
DukeComment
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Re: GL-5
In my experience the only "bad" thing regarding synthetic oil is that it will leak where dino juice wont. Adding it to a medium to high mileage component will most likely result in a leak at the seals. The synthetics have smaller molecules vs the old reliable rotted plant/animal matter made by mother nature. So it will find all the "holes" before regular oil will. If a component is rebuilt to spec. with new seals and seal surfaces by all means use it after a short break-in period with regular oil. I like the benifits of synthetics, but learned the above the only way there is to learn-the hard way of course.Comment
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Old Wive's tale or do you have
specific evidence to back this up? In my experience, this is a much-perpetuated old wives tale that has no credible evidence that this actually happens. I bet this gets passed around by word of mouth better than most myths. Can you support this statement?
Fwiw, I use synthetic gear lube in 72 Corvette as well as my 79 Mercedes diesel without leakage. Now, I am not foolish enough to call a sample of one, proof that synthetics don't leak, but I am happy with them.
GaryComment
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Re: Old Wive's tale or do you have
I was told by a phone tech not to use Mobil 1 in a older corvette, that it would leak. now he could be just passing on bad infor also. but he did recomend me using the delvac as what Duke preaches on here. this was last summer when I called ask Mobil.Comment
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Re: Old Wive's tale or do you have
I was told by a phone tech not to use Mobil 1 in a older corvette, that it would leak. now he could be just passing on bad infor also. but he did recomend me using the delvac as what Duke preaches on here. this was last summer when I called ask Mobil. call and ask them.Comment
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Re: Old Wive's tale or do you have
The one trouble with email is that you can't hear the tone of the question. My point in asking is that I BELIEVE this to be a myth without basis, only because I have read this here and over at the forum where anything goes (CF) . I haven't found anyone that can show a study, document or anything verifying that this is an issue.
GaryComment
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Re: Old Wive's tale or do you have
Being a mechanic most of my life,my experience is that adding/changing to synthetic (or blends) oil where organic oil has been originally in mid to high mileage/hour machinery you can almost always count on a leak at a seal where there was little to none before the change. A seal and its seal surface that has taken its "set" with organic oil wears the two components in a certian manner to promote the sealing of the oil. There is usually a groove in the metal and the seal mating surface has worn a bit too. Synthetic oil with its smaller molecular make-up will find its way through this area. They are usually thinner in viscosity which further promotes leakage. This applies to everything from lawn mowers to semi trucks to 20,000 cubic inch Waukesha natural gas engines. Then sometimes there is a seal incompatibility issue where the rubber will react to the synthetic oil,more so in hydraulic systems. It sounds like I dont like synthetic oil,on the contrary. The benifits of synthetic out weigh the dino juice 10:1 in my opinion. I have lab results,oil analysis,extended oil change intervals,dynomometer peak hp/torque graphs and experience that prove this. That said, you can run it all you want it shouldn't hurt anything unless something runs dry from a leak, but be prepaired to oil down the car and the enviroment. The only way I have sucessfully stopped this in a component such as a diff housing, trans output shaft,main seal etc... besides a rebuild, is to replace the seal, pack grease behind the new one before installing it(general rule here) and putting a CR "speedy" sleeve over the seal surface. 'Have done so quite successfully a number of times. Another way around this if your looking for added protection but dont want to go around and reseal everything is to run an additive such as Prolong, Slick50 or Lucas. I have used all 3 with great success. Machinery that started life with synthetic oil should remain with it for the life of that machine. That's another story. I ditto everyone on the Delvac, Rotella "T", Caster Oil, Valvoline and other "high end" HD comercial oils. I swear by Schaeffer Oil products. Expensive but they use a better base than the garden variety oils. Hope this clears the air a bit and was helpful.Comment
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Re: Old Wive's tale or do you have
well said, amen brother.Comment
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