Syn vs dino gear lube?

[disturban]

What are the advantages of running synthetic gear lube vs dino gear lube? Our truck has about 160k on it now, we bought it used with 80k on it and I changed both diffs at 100k with dino 80w90 Gl5, I am thinking of changing them again but the synthetic is so expensive however I off road a lot and tow a lot with this vehicle and I really would like to avoid changing diff fluids every 80k so would switching to a synthetic allow me to extend my change intervals? Is there any other benefits to using syn? It went 80k on dino twice and shows no sign of failure so I am wondering if I should just stick with the cheapest dino I can find and change it again in a few years?

 

[Rob_Roy]

In over-the-road applications synthetic fluids (and high end conventional) offer reduced operating temperate, longer seal life, better flow in cold weather, and extended drain intervals. With that said, if you do a lot of off-roading you will probably "condemn" the gear oil with water or dirt before wear metals get too high. Synthetic gear oil will not do you any good if the diff. gets contaminated with water.

Personally I think 80k is a stretch with low-bid gear lube in a towing/offroad application. I would probably drop it out every 30-40k, but that's just me.

A common drain interval for synthetic gear oil in light trucks is 50k in severe service, 100k in normal service.

 

[Eddie]

I see no reason to change what has worked well for you.

 

[mechtech2]

Every 80K? That's a good long time!
I'd stick with your dino.

 

[Doug Hillary]

Hi,
disturban - You are well advised to stay with a Mineral lubricant, it has served the purpose well!

Synthetic gear lubricants work very well and perform better than their Mineral sulphur based cousins. This is shown in less deposits resulting in longer seal life. Bearing and gear life is typically enhanced too and a great benefit is the lower operating temperature - this tells its own story! It could be argued that the drive line is the very best application for synthetic lubricants in the Auto Industry and a sygnificant contributor to better fuel economy and the better use of resources due to longer OCIs

Changing from long term use of a Mineral gear oil to a Synthetic can introduce issues such as seal weepage etc.

 

[artificialist]

Non-synthetic gear oil usually isn't available in 75w90 or 75w140, and those viscosities are an improvement if you drive in extreme cold.

Also, it would be less likely to shear into a lower viscosity oil, protecting you better at high temps.

 

[INDYMAC]

Originally Posted By: artificialist
Non-synthetic gear oil usually isn't available in 75w90 or 75w140, and those viscosities are an improvement if you drive in extreme cold.

Also, it would be less likely to shear into a lower viscosity oil, protecting you better at high temps.


Valvoline offers 75W90 and 85W-140 petroleum based GL5 gear oils and are readily available at AP stores.

 

[mechtech2]

Originally Posted By: Doug Hillary
Hi,
disturban - You are well advised to stay with a Mineral lubricant, it has served the purpose well!

Synthetic gear lubricants work very well and perform better than their Mineral sulphur based cousins. This is shown in less deposits resulting in longer seal life. Bearing and gear life is typically enhanced too and a great benefit is the lower operating temperature - this tells its own story! It could be argued that the drive line is the very best application for synthetic lubricants in the Auto Industry and a sygnificant contributor to better fuel economy and the better use of resources due to longer OCIs

Changing from long term use of a Mineral gear oil to a Synthetic can introduce issues such as seal weepage etc.


Nice.

 

[disturban]

I think I am going to switch to synthetic. I will just change the pinion seals and axle seals when I drain the old fluid, it is not that hard of a job and all seals will cost about $50.

My goal is to never have to mess with the diffs again and I hope to get another 100k out of the truck, I think that is reasonable as I have maintained it very well and at 160k it does not leak or use any fluids at all and mechanically it is in perfect condition and everything works like it should.

 

[artificialist]

Originally Posted By: INDYMAC
Originally Posted By: artificialist
Non-synthetic gear oil usually isn't available in 75w90 or 75w140, and those viscosities are an improvement if you drive in extreme cold.

Also, it would be less likely to shear into a lower viscosity oil, protecting you better at high temps.


Valvoline offers 75W90 and 85W-140 petroleum based GL5 gear oils and are readily available at AP stores.


That is why I said USUALLY isn't available.

 

[Y_K]

You may look into Chevron Delo ESI line of gear oil. Or Mobil Delvac 1. Both offer very long life and superior protection to the OTC offerings.

 

[MetalSlug]

AMSOIL Synthetic Gear Lube SAE 80W-90

 

[abs]

For some available options, check my last post in this thread.

My OEM fill was a dino 80w-90 and I created an list of some of the more well known options available to me in the 80w-90 and 75w-90 weights including viscosity differences at 40C and 100C. At the moment I'm leaning toward Delvac 75w-90 since it is a certified synthetic and meets the requirements for long drain intervals for a number of manufacturers. However, there are many good options available. The 80w-90 Delo also is certified to meet many of the same specs and is said to provide synthetic like performance but is dino based and less costly. I know less about the other options, but all the product data sheets are available online with a simple search.

 

[mongo161]

I just picked up 6 quarts of Mobil 1, 75W-90, Synthetic gear lube for the Differentials and transfer case in my T4R. I plan on changing out the fluid very..... soon weather permitting.

I ordered on line and picked up at Advance Discount Auto parts. Use the discount code VISA and get a $30 discount on a $75 purchase. I ordered 6 Quarts of Mobil 1 Gear Lube and 2 Quarts of Mobil 1 ATF to get to $75.

I plan on changing out the ATF in the fall to Mobil 1 so I'll start stockpiling a few quarts here and there. It will take about 14 to 16 quarts to have the fluid exchanged in my T4R.

So...I'll buy a few here....then I'll buy a few at another time until I get to my 16 Quarts.

 

[mongo161]

I had checked out the Walmart, in NJ, to see if I would save any money by buying the SuperTech Gear Oil.

The answer was no. There is no savings by going to my WM.

The SuperTech synthetic Gear Oil 75W-90 was a only a "Blend Gear Oil" at $4.XX a quart. The full synthetic gear oil was $11.XX a quart and a higher weight like 80W-140.

So by going to advance and buying the Mobil 1, 75W-90, Full Synthetic with LSD....the cost per quart, after online coupon code discount was less than $5.50 a quart. The normal price is almost $10 a quart.

IMO...if Mobil 1 in 75W-90 Synthetic is what you're looking for....Advance is the best deal with buying on line, using the coupon codes and picking it up at the local store.

 

[spasm3]

I thought i would bring back this thread.

I just had my rear end rebuilt by east coast gear. They recommend that i use dino oil as opposed to synthetic. They claim it does not stay on the gear as well as dino.

They do recommend lucas gear oil. I generally don't allow anything lucas near my vehicles. They do a lot of differential work. I had new gears, bearings and a tracrite posi unit installed.

After 500 miles i will change the gear oil. They only recommend dino- 75-140 oil. I'm thinking valvoline or castrol non syn gear oil.

Thoughts?

 

[RooflessVW]

Differentials operate in an oil bath. Use what they want under warranty, I suppose, but keep in mind that there is no conventional 75W-140. Conventional gear oils are typically 80W-90 or 85W-140.

 

[spasm3]

Originally Posted By: rooflessVW

Differentials operate in an oil bath. Use what they want under warranty, I suppose, but keep in mind that there is no conventional 75W-140. Conventional gear oils are typically 80W-90 or 85W-140.



Yes i got it wrong, it is 85-140

 

[zeng]

Listen to the rebuilder.
Go for dino 85W140.
I swapped an 80W90 with SAE 140 in work trucks.

 

[MolaKule]

Originally Posted By: spasm3
I thought i would bring back this thread.

I just had my rear end rebuilt by east coast gear. They recommend that i use dino oil as opposed to synthetic. They claim it does not stay on the gear as well as dino.

They do recommend lucas gear oil. I generally don't allow anything lucas near my vehicles. They do a lot of differential work. I had new gears, bearings and a tracrite posi unit installed.

After 500 miles i will change the gear oil. They only recommend dino- 75-140 oil. I'm thinking valvoline or castrol non syn gear oil.

Thoughts?


Was the recommendation for mineral oil diffy lube just for run-in or for the life of the diffy?

Did they give any technical reason for recommending mineral oils over synthetics?

All gear oils, whether synthetic or mineral have surfactants so the splashed lubricant coats all parts and brings the EP additives to the high load contact points and surfaces.