Is there a consensus here on differential oil?

I have to change the oil in my diffs and tranny (4wd, 6sp TRD Sport). It seems like the oils of choice here are redline and amsoil severe gear. Since neither is cheap and they're about the same price, is there a consensus on which is best?

Also, is the redline MT-90 just for the tranny and regular

$28 75w-90 Synthetic Gear Lube - 1 Quart (Pack of 2)

75w-90 for the diffs and transfer case? Or will 75w-90 work for all of them if i go with the amsoil?

Thanks for any help, brohiems

 

Pick your color. Also, you'll need LS additive.

 

I use MT-90 in my trans and transfer case. Mobil 1 in my diffs. Been working great for me.

 

I have the LSD additive.

Is mobile 1 good? My truck loves it in the engine but i heard it's not great in the differentials. Is that true?

 

Also, is there any benefit to putting a higher viscosity oil in the rear diff?

 

It works great in my diff.

 

I have been corrected, sports DO NOT have a mechanical Torsen, the DO have CLUTCH LSD's and will therefore require anti-slip modifier additive.

̶L̶S̶D̶ ̶a̶d̶d̶i̶t̶i̶v̶e̶ ̶i̶s̶ ̶n̶o̶t̶ ̶n̶e̶c̶e̶s̶s̶a̶r̶y̶ ̶f̶o̶r̶ ̶t̶h̶e̶ ̶T̶a̶c̶o̶m̶a̶ ̶i̶t̶ ̶u̶s̶e̶s̶ ̶a̶ ̶H̶e̶l̶i̶c̶a̶l̶ ̶T̶o̶r̶s̶e̶n̶ ̶s̶t̶y̶l̶e̶ ̶m̶e̶c̶h̶a̶n̶i̶c̶a̶l̶ ̶l̶i̶m̶i̶t̶e̶d̶ ̶s̶l̶i̶p̶ ̶i̶n̶ ̶y̶e̶a̶r̶s̶ ̶0̶5̶-̶0̶8̶ ̶a̶n̶d̶ ̶e̶l̶e̶c̶t̶r̶o̶n̶i̶c̶ ̶c̶o̶n̶t̶r̶o̶l̶l̶e̶d̶ ̶b̶r̶a̶k̶i̶n̶g̶ ̶f̶o̶r̶ ̶0̶9̶+̶ ̶v̶s̶ ̶t̶h̶e̶ ̶c̶l̶u̶t̶c̶h̶ ̶p̶a̶c̶k̶ ̶s̶t̶y̶l̶e̶ ̶l̶i̶m̶i̶t̶e̶d̶ ̶s̶l̶i̶p̶.̶

That said the below stands true.

No clutch packs means you're blowing money for no reason on LSD additives.

I personally would recommend Mobil1 or Amsoil Severe Gear if you're really concerned, each in

$28 75w-90 Synthetic Gear Lube - 1 Quart (Pack of 2)

75w-90.

Really any gear oil in the correct weight will do just fine as long as it's changed on schedule.

If it meets JSO its good enough.

 

No.

 

Who told you that!? M1 is probably the best off the shelf box store stuff you can get.

 

All the threads I read said until '09, they needed LS additive. Even if using LS Mobil 1, you still need to add more LS additive or you'll get clicking/groaning/moaning. I guess all those threads were wrong.
I have an OR w/rear locker & just today put in Mobil 1. Some say the locker doesn't like it but I see no reason it wouldn't. We shall see!

 

God I love MT-90. It's been like magical unicorn spooge for me.

My 1st gen R150F wouldn't go into 1st or 3rd when just starting up and the fluid was cold, changed out to MT-90 and after 3 weeks of normal driving it would pretty much fall into each gear readily.

I put MT-90 in my 2nd Gen's RA60F and been very happy with it too.

Redline is damn good stuff.

 

Bizarre, a mechanical LSD needs nothing but gear oil. The friction modifier is there to prevent clutch style viscous coupler LSD's from slipping.

I ran Mobil1 in my 00 with dif lock and now in my 10 with dif lock, no issues in either, locker still engages quickly and quietly.

 

Wrong, wrong, wrong.... wrong...

05-08 tacomas equipped with a mechanical LSD most DEFINITELY had clutch packs. Pulled straight from the service manual. You can buy the clutch packs for them, there is even a spec for a new clutch pack, 150ftlbs it should take to be able to make the clutch pack slip.




OP, Mobil 1

$28 75w-90 Synthetic Gear Lube - 1 Quart (Pack of 2)

75w-90 has LS additive in it, some have stated its not enough so they add a lil more in (they sell just LS additive in lil bottles)

 

I stand corrected then, I was told the 8.4 was a mechanical LSD, either the person I was talking to misunderstood that mechanical LSD is used to refer to a a worm gear style "Torsen" and clutch LSD is called a clutch LSD or he had bad information.

In which case yes you will need additive to prevent slippage.

Also I now don't feel bad about not having a sport LSD axle. I hate clutch style LSDs.

Stand by editing my post.



Thanks mate.

 

People discern between mechanical and non because, technically a clutch pack style of LSD is infact fully mechanical, there are no electronics, no simulated lsd with brakes etc in them. 09+ trucks lost the mechanical LSD in favor for a simulated LSD with the use of the traction control system stopping or slowing the tire that is spinning faster.

the 8.4in diff has a fully open flavor, and the mechanical LSD flavor, the mechanical LSD (clutch pack style) was optioned on 05-08 trucks, but like stated 09+ trucks do not have any option for mechanical lsd.

 

That's what I thought.

 

If you tow a lot or drive in 4 lo a lot, you might slightly benefit from 75-140. Probably would never notice the difference, though.

 

My education if you will comes from back in the day road course stuf long before there was such a thing as a simulated electronic tonic LSD. On the track you were either open diff, or you had a clutch LSD both spring or viscous coupler engagement, or a mechanical LSD. Torsen or Eaton style refered to as mechanical because of the worm gears that gave you the LSD properties. Clutch pack LSDs having slightly different performance characteristics and fewer mechanisms.

Torsen LSD:

 

The drop in MPG from having to churn that molasses would be more noticeable than any benefit from the thicker fluid.

If you're trying to extend longevity of the diff gears your biggest problems are heat and fluid breakdown, which is primarily due to heat.

Thicker fluid won't do much for either.

You want to keep your fluid cool and have one that will run cooler. Heat wise full synthetic is about all you can do there short of attaching cooling fins to your pumpkin.

The other end of longevity is breakdown, for that you need a fluid that has a higher pressure rating, for instance Amsoil Severe Gear. A higher pressure rated fluid will degrade from being crushed or sheared significantly slower and will provide more cushion in between metal and metal contact.

 

Mobil one is good oil, but does not come in higher viscosities, if you need that. If you settle on a lower weight oil, it is a good choice. You WILL need an LSD additive, regardless what it says on the oil bottle.