Synthetic lube for the rear axle?

[Maverick]

The only time I use synthetic is when it's required/OE like the rearend on my Superduty. If it wasn't, I sure as hell wouldn't be spending $13 a quart on gear oil. All of my other rearends/trans/t-cases/motors have survived just fine with regular oil, and I abuse shit.

 

[mhughes165]

The only time I use synthetic is when it's required/OE like the rearend on my Superduty. If it wasn't, I sure as hell wouldn't be spending $13 a quart on gear oil. All of my other rearends/trans/t-cases/motors have survived just fine with regular oil, and I abuse shit.

why waste the money on something that doesnt need it, if it required it im sure they would say so, my buddy has a 85 chevy van with 380k miles on the original engine, starts runs and drives every day with no issues and JUST went through state inspection, has had no major repairs and gets walmart brand bulk 5w30 oil in the engine and had the original gearlube in the rear end

 

[chazzone]

my personal reasons dont have a whole lot of science backing them...just personal experience.

firstly, i started to notice a trend on vehicles with synthetic motor oil. everytime i dropped the oil on one, it came out caramel or even gold in color (read: clean), and the oil filter weighed a bazillion pounds. that tells me that synthetics dont suspend particals as well as dyno oil does, thus loading the filter full of crud.

What this really tells us is that the "crud" is in your filter, where it belongs instead of eating up your engine.

but mostly, i just cant justify the expense. we have several regular customers with more than 200k, and even a few with over 300k miles on dyno oil and their engines still run fine. if you ask me, thats overhaul territory anyway. and its cheaper for me to change my dyno oil every 3k miles than it is for the synthetic guy to change his every 5 or 6k.

One of the main advantages to using a good synthetic is that you don't have to change your oil every 3k miles. I had my oil tested for about a year, and the Full Syn Castrol didn't even start to crack after 8,500 miles!

I change my filter every 3k, but the oil only gets changed every 9k. This means I can justify paying 3 times the price for oil, and since I buy it on sale, I'm not paying near that.

-zz

 

[Wicked_Sludge]

What this really tells us is that the "crud" is in your filter, where it belongs instead of eating up your engine.

see post #14

I change my filter every 3k, but the oil only gets changed every 9k. This means I can justify paying 3 times the price for oil, and since I buy it on sale, I'm not paying near that.

i just bought 5 quarts of valvoline today for $13. last time i checked locally, mobil 1 was about $8 a quart. thats a little more than 3X the price

and your assuming everyone is going to spend the time and money to have their oil tested, and that everyone would be able to get away with 9k mile oil changes. it works for you, but i know my crappy, high mileage, high sludge motors would dirty the oil up faster than that...thus the cost is too high.

like i said, my reasons are essentially personal. to each his own

 

[MAKG]

There are several reasons one might use synthetic in a crankcase, but they aren't the ones usually cited:

1. Extreme low temperatures (e.g., arctic trucks); synthetic has a very low pour point. But you could use a block heater....
2. Severe service (perhaps some offroading qualifies -- extended low speed high torque situations). Synthetic tolerates higher temperatures BUT conventional is adequate for normal service.
3. Solving oil-use detonation (synthetic doesn't burn the same way as conventional).

Not much else. You could go to extended oil change intervals but you really have no idea without a used oil analysis (it is NOT the same as your buddy's even if he has the same model and year truck).

The color doesn't tell you anything. You could also explain that as synthetic not making the small pieces that should go in suspension. A used oil analysis will clear some of that up. It could also be a crappy synthetic (they AREN'T all the same -- Castrol Syntec isn't really synthetic, and non-API oils could be just anything).

As for why one might use synthetic in any other part of the drivetrain, there really isn't any reason. Not even the limited slip argument -- you CAN forgo that with conventional if a little chatter doesn't bother you (the LS will actually work better without it).

Some people have to change drivetrain fluids more frequently, e.g., due to water crossings.

 

[engdept]

Some people have to change drivetrain fluids more frequently, e.g., due to water crossings.

They wouldn't have to change the drive train fluids more often if they would extend the breather tubes to the upper engine bay.

 

[OilPatch197]

As for why one might use synthetic in any other part of the drive train, there really isn't any reason.

So you're saying there will be no efficiency gains by switching to synthetic?

 

[85_Ranger4x4]

They wouldn't have to change the drive train fluids more often if they would extend the breather tubes to the upper engine bay.

Any time water gets over the hubs it is a good idea to do, what holds in gear oil may not hold out water.

My F-150 came with synthetic oil in the axles, I can't say I have noticed much of a difference in "axle performance" between it and my Ranger with its more than likely circa 1985 dino oil in the axles. They both run nice, smooth and quietly down the highway like they are supposed to, can't improve apoun perfection really.

I run motorcraft synthetic blend motor oil in my F-150 and it works fine. It does still turn a little darker like it should, and compared to the FL-1A I have been changing on my Ranger for 8 years I still haven't gotten used to the puny FL-820S... it always feels light to me.

I tried running synthetic blend in my Ranger, it either leaked or burned it. It didn't stay in the engine near as long as regular does... and it was more expensive.

 

[engdept]

I might need to switch back to regular oil in my Bronco II. The synthetic blend I use about 1 quart per oil change and have a leak by the oil filter somewhere.

 

[MAKG]

So you're saying there will be no efficiency gains by switching to synthetic?

Yes. That synthetic is "more slippery" is a myth. Viscosity is viscosity.

 

[Mac]

Synthetic or not, I like to always do the first and only change in the rear end at somewhere under 10K miles. You will find a lot of little "stuff" when you drain it. Like someone said, rear end ought to last 60 years after that. Water crossings, yes, be smart and drain and change fluids.
Dave

 

[OilPatch197]

Synthetic or not, I like to always do the first and only change in the rear end at somewhere under 10K miles. You will find a lot of little "stuff" when you drain it. Like someone said, rear end ought to last 60 years after that. Water crossings, yes, be smart and drain and change fluids.
Dave

See that is how I F'ed up this axle, we have seasonal flood waters floods our township road about twice, or more every year, and it gets generally around 1ft to 3ft deep. I have to cross it, and I do that by "riding the wave".

You basically start slow and a wave will form infront of the truck's bumper, you stay with it until you're on the other side, you got to go fast enough to keep the water from plugging your exhaust, once water covers the exhaust, the motor cannot handle the backpressure, and dies. Been thru that many times. Planning to build a tight exhaust with a snorkel attachment.

What happened was my breather tube popped off by the force of the water and I think that is how I got water into the axle, So this time it will be well clamped, and the hose will be ran up behind a tail lamp.