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Is Synthetic Gear oil a bad idea?

O

Oilbrnr

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I know that it is not a good idea to switch to synthetic oil on a high mileage engine due to a tendency to create leaks, but is the same true in say the SM465/NP205/diffs? The '77 I just got is has no leaks currently from these areas, and I just as soon keep it that way. I have a bunch of Mobil 1 that I run in my Dmax Sierra that I was thinking about using in the K5. Thoughts?
 
I live in your same valley . I run Redline Heavy Shockproof in my rear diff year round . If I can't find Redline the day I need it , I found Royal Purple works just as well . Thats for wheeling .

If it is open diff no wheeling the Valvoline/Mobil stuff at Autozone is fine :thumb:
 
Synthetics don't really "cause" leaks they just find the leaks that normal oil is to big to get through. I would definitly switch to syn. I run synthetic in my DD diesel and also have been running syn in my K5 offroad truck for a long time in the diffs, and now the motor.

Doing good maintenence is the key to longevity and using good syn. oils will help it even more.

Harley
 
going to buy some of this Redline Heavy Shockproof for my 1 tons, want to keep them around awhile! also bought the hub socket to repack the bearings..

question, is there a synthetic for grease, hubs nipples etc
 
i read somewere you need special rtv sealent or a new gasket for synthetic oil use. it eats away at std rtv from what i recall. :confused:
 
sweetk30 said:
i read somewere you need special rtv sealent or a new gasket for synthetic oil use. it eats away at std rtv from what i recall. :confused:
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Old tales die hard, no, synthetic lube is just not organic so it doesn't oxidize the same as the conventionnal oils and it's also produced in very low viscosity and high temp performance, the only problem is leaks and blow by if your engine is not tight, same with diffs and trannies/tcases.
I used all synthetic in my 79 van with very low miles engine/ axle.
My tranny was auto and at the time couldn't find any ATF synth, I did that for 5 years, I changed the engine oil once a year and never touched the diff lube just checked it.
I love it, less time to do changes longer intervals and better performance, I believe it's worth the money spent.
 
chevyguybc said:
i wasnt talking rear wheel bearings, i know they are lubed by the grease, i was talking front dana 60
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There is grease in a FF?
:rolleyes:

Guess I'm old school, but I always remove, clean, and hand repack tapered bearings. That way I know that they are still serviceable.
 
As eariler post said" Old Tails Die hard"
Back in the 70s When syn oils first came out they did not contain the aeromatics and other chemical compounds than perserve seals.
Syn oil was refined so pure that it dried out seals and caused leaks.
Oil companies soon corrected their mistake and put additives in Syn oil to perserve seals.
But the old tale of Syn oils causing leaks still lives on.
I have switched to syn oils in engine/drivetrain in various vehicles with well over 100K miles with no bad affects or leaks.
 
Using Synths in old design axles & T-cases shouldn't be a problem because axles & t-cases don't have high pressure pumps. Engines & trannies are are different story. Mine did leak.
 
Yes there is synthetic grease's. I know Amsoil makes them and I am sure you can probably find Mobil 1 & others too. I personally use water repellent grease for boat trailer wheelbearing for my front wheelbearings, aka Green Grease.

Harley
 
chevyguybc said:
going to buy some of this Redline Heavy Shockproof for my 1 tons, want to keep them around awhile! also bought the hub socket to repack the bearings..

question, is there a synthetic for grease, hubs nipples etc
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That is some kick arse gear oil. I use it in my K5 and have for about 6yrs. I am the one who turned Pauly onto it. The only downside to that oil is it isn't really intended for trucks that see alot of road miles. I DD'ed my K5 just fine with it though so as long as your not running a million road miles you should be fine.

I am stoked, I got word the other day Amsoil finally has a 75w-250 (same as Redline heavy) gear oil in the works. The redline is good stuff but now that I am an Amsoil dealer I get a discount on it when they bring it out. :D

Harley
 
Chevy305 said:
Talk to Tom (4by4bygod) he has the perfect solution for all your lube needs ;)

http://coloradok5.com/forums/showthread.php?t=192545
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Thank You Glenn ( not forgetting you either, Brent).. the thing about synthetic this versus dino that is that nowadays, ( thanks to the castrol court case ) anything can be legally called a synthetic. It's a marketing term, not an indicator of performance.

used to be, all synthetic meant was " highly refined" - all "highly refined" meant was that each molecule was "synthesized" to be the same size..that's why cheap oils "glop" when you pour them, ( varying molecule size )and real synthetics don't. they were also a superior oil for this reason. the oil got where it needed to go much more quickly, and you got a bit of a friction reduction.

FWIW, all lubes are petroleum..the difference is in point of origin in the carbon chain, and level of refinement. for example, PAO synthetics come from liquid natural gas molecules. mineral oil comes from the ground in carbonaceous liquid form and is refined into something useable..these are your group I, II, and III petroleum oils. Esters are a group above PAO's on this scale.

what's more important than labelling or marketing is formulation.. PAO oils without adequate esters will attack seals and cause leaks. both PAO and ester oils attract moisture.. even if you have the perfect balance of PAO and ester with no leaks, high heat will render the basestock unable to hold onto the EP additives ( and even they vary in quality and ability ) for any length of time, and any shock loads will hurt the lubricant as well. PAO's are not known for their ability to hang onto their additives.

Moly is especially susceptible to being " shattered" when a shock load is applied to a lubricant, and guess what oil companies are using to replace zinc, sulfur and phosphorus? sinterable metallics are not the answer.

for gear oil, you might be looking at a group II or III basestock, and that's just a mineral oil, that may not be refined to the point where all of the molecules are the same.. they're easier on seals, but they're not so good for reducing friction - unless you additize the crap out of them, and again, the amount of heat the oil can absorb will dictate how successful the additive is in doing what you want.

ester base gear lubes are nice on seals, but again, they do attract moisture - that's a big deal to some folks. the more expensive gear oils will have better tackifiers ( you don't want crap like lucas in there thickening everything ) but as always, heat is the enemy of additive retention.

important thing is to check out specification and msds sheets, and know the marketing from the science..

as always, you guys can buy what you want - just know what's going on with what's out there. If you want to see the next step beyond synthetics,as glenn says, the answer is just a click away..
 
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