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Ok So i see this has been beaten to death back in 2003 but now i am confused. My truck does not have a LSD i jacked the rear up and the wheels turn in oppisite direction. There is a big red sticker on my diff that reads "USE LSD OIL ONLY" whats that all about??? Should I just contact the dealer on this? I have had this truck for a bout 20k miles and bought it used with 120k miles on it. I dont think the front and rear diff oil had ever been changed I dont think the tranny has been flushed ever and I dont think the transfer case has seen new fluid ever.... Any recommendations? I am looking to do the transfer case front and rear diffs myself.
 

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Re: front and rear differencail and transfer case oil change?

So change it. 75-90 in the front diff and transfer case and 90 in the rear diff. I would use the best syn. you can buy, either amsoil
or mobil 1. I believe there is a 80-140 or something similar for the rear and 75-90 for the front and transfer case. 3 quarts of each
should do the job. Add just a touch of the lighter oil to the rear diff. to bring it to full, 3 quarts is just a tad shy of full.
 

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Discussion Starter · #3 ·
Re: front and rear differencail and transfer case oil change?

Ok so one question. I just spoke to the dealer and the were super helpful in giving advice but they recommended not to go with a synthetic and he explained that synthetic has a smaller molecule size than conventional and my t-case and diffs might start leaking if i switch to synthetic after being on conventional for 140k miles. Any thoughts on this????
 

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They may, but it's worth it. You should see an increase in mileage. 1/2 MPG or so. And it will help your gears and bearings
live. Seals are cheap and some of the synthetics have seal swelling additives now. Oh, I never have heard anything about the
molecule sizes. It is the fact that synthetics don't condition the seals as well.
 

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Discussion Starter · #5 ·
Ok I am looking at GL5 for the t-case and front. Should I be concerned about the "USE ONLY LDS FLUID" sticker on the rear diff? It is not a LSD (for the wheels do not turn the same direction when rear is jacked up) unless this directional movement of the wheels can change depending on the condition or the level of the fluid?????
 

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Either way, your clutches are shot if they are in fact in there, so regular oil won't hurt, and the additive won't hurt a non limited slip
if you use it. You are thinking to hard here.
 

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Discussion Starter · #8 ·
Thhank you for the info that was helpful... I did just confirm with Toyota that my truck has infact a LSD!!!!! I know for a fact that my wheels turn in oppisite direction when the rear end is in the air so i think you might be right on the shot clutch thing but if I want to fix it what would be the cost? more or less? i would like to think there isnt really anything wrong for it doesnt make any noise at all. I think I need to go ly down my head is spining!!! :mad:
 

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Discussion Starter · #9 ·
Can i put this pil in my front, rear and t-case???

Mobil 1 Synthetic Gear Lubricant LS 75W-90

or

Mobil 1 Synthetic Gear Lube LS 75W-140
 

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Re: front and rear differencail and transfer case oil change?

Ok so one question. I just spoke to the dealer and the were super helpful in giving advice but they recommended not to go with a synthetic and he explained that synthetic has a smaller molecule size than conventional and my t-case and diffs might start leaking if i switch to synthetic after being on conventional for 140k miles. Any thoughts on this????
When dino-oil gets dirty enough and remains in an engine, (axle, whatever...) the suspended dirt will coagulate, adhere to itself and form "sludge". Sludge often settles around seals and gaskets isolating them and allowing them to dry out and thus shrink slightly. As long as the sludge stays in place it doesn't allow the dino-oil to exit (leak) from the weakened seal. Introduce synthetic oil into the environment with it's strong detergents and it will clean away the sludge that's formed. Remove the sludge band-aid and the dried/shrunken seal will then leak. Depending on how long the seal has been damaged it's common for them to re-expand and re-seal themselves once they get clean and re-treated from the inside.
 

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Re: front and rear differencail and transfer case oil change?

When dino-oil gets dirty enough and remains in an engine, (axle, whatever...) the suspended dirt will coagulate, adhere to itself and form "sludge". Sludge often settles around seals and gaskets isolating them and allowing them to dry out and thus shrink slightly. As long as the sludge stays in place it doesn't allow the dino-oil to exit (leak) from the weakened seal. Introduce synthetic oil into the environment with it's strong detergents and it will clean away the sludge that's formed. Remove the sludge band-aid and the dried/shrunken seal will then leak. Depending on how long the seal has been damaged it's common for them to re-expand and re-seal themselves once they get clean and re-treated from the inside.
Very well put Timberline. :tu:
In essence, if the addition of synthetic oil causes an oil leak, then your leak was already there. The new oil isn't the creator of the leak, it's the cleaner of the wound.

So yes, your dealer is correct, in a sense. But Timberline is correct all the way.
 

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first off very well said timberline i have had some experience with this first hand as i switch from dino-oil to synthetic 75-90 Mobil-1 and had some minor leaks show up on the transfer case and then disappear after a little wile and have had no problems sense. i am still using 75-90w Mobil-1 in the front, rear and transfer case.
 

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Ok I am looking at GL5 for the t-case and front. Should I be concerned about the "USE ONLY LDS FLUID" sticker on the rear diff? It is not a LSD (for the wheels do not turn the same direction when rear is jacked up) unless this directional movement of the wheels can change depending on the condition or the level of the fluid?????

I agree with the advice of going with synthetics. One question I have though is
what gear did you have the truck in when you had it jacked up and turned the tires?


John
 

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first off very well said timberline i have had some experience with this first hand as i switch from dino-oil to synthetic 75-90 Mobil-1 and had some minor leaks show up on the transfer case and then disappear after a little wile and have had no problems sense. i am still using 75-90w Mobil-1 in the front, rear and transfer case.
I have a 2006 4WD with 68,000 miles. All the grease got changed with dino at 30,000 miles and I'd like to put in synthetic next. Anyone have experience with significant leaks after switching on a vehicle with roughly this mileage and age of existing fluid? I'm not up for significant leaks.

Thanks in advance,

Fred
 

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My rear tires have turned opposite ways from day one (yes, it is an LSD), but when it's been powerbraked, or just beat on it leaves two black stripes and gets a little sideways.

If I use Mobil 1 synthetic I wind up with "chatter" in the rear and have to add some LSD/Positraction lube. If I use Redline gear oil it stays chatter free....
 
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