Dino vs syunthetic in SUV Differentials?

[Scottydog]

I read a comment that some of the axle manufacturers won't warranty differentials if synthetic gear oil is used. The claim is the fluidity of the synthetic won't adequately lubricate the gears?

Any thoughts?

 

[ryan2022]

Read this post. I did a lot of legwork trying to descide this for myself.

I talk to a few axle manufacturers and they seem to have varying opinions.

In the REAL world, there are a lot of cases of very high mileage diffs running synthetic on longer drain intervals.

Gear sets are different beasts, I beleive they need a break in period, just like an engine. I think in SOME cases the hardening of the gear sets can take a while longer with syntheitc due to the heat reduction.

A lot of the builders also build high pinion diffs.....Currie.

They claim that dino clings to gear better and climbs. If youre not running a high pinion axle, its a wash. Gear oil is flung and that actual contact point of the gears is usually submerged in oil.

I jumped the gun and went to conventional, then went back to syn at the end of the summer. I would use it without worry.


http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=1584408#Post1584408

 

[Scottydog]

Thanks for the info. I knew this issue had to have been investigated.

The 05+ Jeep Grand Cherokees front diffs seem to have high pinion gears. A guy had his front axle replaced 3 times in one month with oem axles. A Chrysler rep came to the conclusion the factory fill (1 cm under the fill hole)didn't lubricate the pinion gear, when combined with a lift that tilted the vehicle a bit. I haven't lifted my truck, but it sounded pretty touchy in any case.

Since I'm way past warranty I started to wonder if I should go back to dino gear oil. I'm also glad I max filled my diffs!

 

[ryan2022]

Yep, always fill them to the top.

If youre concerned about your front diff, you could go to a dino oil, but I still think youre okay.

My final beleif is that the axle manufacturers findings may be outdated, AND that a good dino gear oil is better than a BAD synthetic all day long.

If you stick with Amsoil, Redline, or any of the higher end names, youre probably fine.

If youre interested, take a read. Its done by Amsoil, so excuse some of the biases.
http://www.amsoil.com/products/gearlubes/WhitePaper.aspx

Also, I'd bet good money, that youre '09 Wrangler is filled with synthetic from the factory. I just read your sig. Nice Fleet!

 

[Scottydog]

I use Redline gear oil. It's been in the GC for over 50,000 miles with no issues, so I guess I won't panic and change the diffs this afternoon. lol

Yea I seem to have a small fleet. It makes for a lot of fluid changes, and frequent bitog discussions.

Thanks guys, BITOG rules!

 

[ryan2022]

Having multiple diffs to change would definetely lean me towards synthetic.

Good stuff!

 

[wgtoys]

Meanwhile, Ford factory fills many rear diffs with synthetic from day one.

 

[PT1]

Originally Posted By: wgtoys
Meanwhile, Ford factory fills many rear diffs with synthetic from day one.


So does GM. But Toyota uses dino. Go figure. Many schools of thought on dino for break in and then syntheic afterward is best.

 

[endeavor to persevere]

Yeah GM has used synthetic oil in its truck and SUV differentials since 1998 as factory fill.

 

[Steve S]

What I would is if the mfg says to run syn I would run syn. If the mfg says to run dino I would run dino . But there is always a but Chevron DELO ESI is a dino that will equal or outperform many syn oils.

 

[Boomer]

Nissan uses syn in their rear diffs and conventional dino in the front diffs in Frontier trucks.

 

[AzFireGuy79]

Toyota also installs sticky throttles....

Couldn't resist. I love my toyotas and Synthetic gear oil!

 

[defektes]

my gmc and silverado both state synthetics only for the differentials

 

[killagt]

Synthetic and dont look back for 4-5 year or more

 

[Ben99GT]

Originally Posted By: ryan2022
They claim that dino clings to gear better and climbs.


That may be [somewhat] true if we're taking about group III or PAO synthetics, but fat chance if we're talking about an ester based synthetic gear oil.

 

[pavelow]

Maybe the gear and axle places are saying to run dino lube for the break-in period so the gears wear to themselves and then switch to syn afterwards. That makes sense and has been standard practice for as long as I can remember.

 

[MonumentOiler]

Could be just saying a two-week 500 mile OCI is a waste of a $12/quart synthetic.

 

[PT1]

Originally Posted By: MonumentOiler
Could be just saying a two-week 500 mile OCI is a waste of a $12/quart synthetic.


Good point. But since we are here at the BITOG anal retentive gear oil site, AND since 90% of people never know their diff oil needs to changed and drive 100-200k on FF with no issues and have been doing this for decades...I think I need to flush my rear diff 2-3 times in the first 5000 miles

 

[unDummy]

The gears decades ago weren't stressed as much as they are now. We are pushing more power and weight through the 'ends and trying to make those gears as cheaply as possible. And, we're using the real world as the test platform since the r&d budget has been chopped up by the accountants.

Toyota have various diffs and some get synthetic.

Some axle manufacturers are too chicken to admit that they sometimes ship a garbage gear set. When they hear that the owner used a synthetic, the ol' Neanderthal mentality kicks in at the manufacturer and the word 'synthetic' is easy to blame. Show me the proof?

 

[JohnBrowning]

Well a lot of GM SUV's ship from the factory with synthetic it allowed to elimanate drain plugs on many axles. That was 3 cents an axle saved. It also allowed them to make a 100,000 mile drain interval claim which is not good!

I like synthetic for it's cold weather performance more then anything else. I have never had a wear issues with dino gear lube and if I lived in the deep south I would probably not be useing synthetic in diff's!