SYNTHETIC OR NOT??

For the first time since owning the truck I’m going to be changing the rear diff, front diff, transfer case and transmission oil in about 2k more miles along with the engine oil. Do you guys recommend I use synthetic for all that or? And what oil is everyone else running?

 

walmart's super tech synthetic all around. Can't go wrong with it and its price

 

Follow my lead, every 50k
I’m at 650,000


T-case is 1.1
Front Diff is 1.6
Rear Diff is 3.

Redline for transmission and tcase

Amsoil for differentials

Be careful removing the front lower differential Allen type drain plug tho.

I had to use a hammer and chisel to get it loose after I stripped out the Allen inset section.

I replaced the Allen bolt with the Lexus bolt shown

 

thank you!

 

For what it's worth, ECGS (East Coast Gear Supply) does not recommend synthetic in the diffs... Doesn't hold up to high temps as well.

 

LOL. That's why we put synth gear oils in our race cars, because it "doesn't hold up to high temps as well."

The WHOLE point of synthetics is they *don't* break down with heat as much as dino.

And you don't need the super duper snake oil expensive stuff either. Valvoline Synthetic 75w/90 or whatever weight you want. The Valvoline full synth gear oil is good stuff.

 

I’ve always run Amsoil synthetic in my differentials and I run my truck hard with the supercharger with 650,000 plus miles.
Never had a single issue with my diffs yet. Just change my oil every 50k or so.

Ended up getting 4 quarts of Amsoil 75w90 GL5 for the front and rear diffs.
Ended up getting 4 quarts Redline MT90 75w90 GL4 for the transmission and Tcase.

And new oil plug crush washers, 8 needed, one is a copper one for the front diff.

Those Amsoil oil bags make oil changes a breeze.

No Messy leaking oil pump needed anymore to pump the oil in.

I reuse these Amsoil oil bags for the diffs and fill the old Amsoil bags up with the redline oil for the transmission and Tcase.
Soo much easier this way

 

You’ll get different opinions. In a truck that close 20 yrs, I would do synthetic for the engine and conventional for the trans, t-case, and diffs
Synthetic can find old dry seal and create leaks a little sooner.

 

Personal Choice I had a few of the different oil reps over the last few years.

Tell me the Synthetic oil is over priced and a waste of money maybe it has improved like other products .

Might be the commission they made was lower on the Synthetic so why push the product.

 

You can always switch back if it leaks,

https://www.idrivesafely.com/defensive-driving/trending/synthetic-oil-vs-conventional-oil

 

That’s an important note also; synthetic and conventional oils can be interchanged.
With a service history, switching to synthetic is a no-brainer.
If the driveline hasn’t been touched in 20 years and 200,000 miles, you may develop some leaks switching to synthetic

 

Doesn't matter, just as long as you change it regularly.

I use conventional on my 04 Tacoma and Synthetic on my '17 4Runner because that's what the manual recommends.

 

how much in the trans? I have a manual 5 speed.

 

i definitely don’t want leaks. So what conventional oil do you recommend using?

 

I don’t have the answer at my fingertips, but knowing that you have a 5 speed, I will endorse redline for this application. I changed to it a few months ago and have noticed that cold weather shifting performance is a bit smoother. The corollary is that long ago I used cheap GL5

$29 75w-90 Synthetic Gear Lube - 1 Quart (Pack of 2)

75w-90 in a Corolla 5 speed transaxle, which made the shifting noticeably worse.

 

I just don’t want to switch to synthetic and start having leaks.

 

I might use amsoil instead

 

Amsoil is synthetic.