Limited slip diff fluids (1 Viewer)

[Leandro]

Hi all
I've been searching the forum and reading the faq for the last couple of days.
I want to replace TX and Diff fluids on my 99 LX470.
My LX has rear LSD, I'm pretty sure the front diff is open.
The manual specifies different oils for both types of differentials (open and LSD), although the viscosity is the same the LSD says "80W90 For Limited Slip Differential".
Would it affect the front diff if I put the same (LSD) oil on both? What if I get the regular 80W90 and add the friction modifier for the rear diff?
I saw a lot of people using 75W90 Synthetic. Would that work for either LSD and open diff? Would the 75W90 Synthetic LS negatively affect the transfer case?
I saw several users reporting that 75W90 worked very well, but I don't know if they were LSD.

I'm trying to simplify the purchase, but since it's not something you change very often, I prefer to do it right.

 

[abuck99]

You can use M1 75-90 in the TX- and the front diff(unless it's locked)- not sure about rear requirements on the 98-99 because of the factory locker. The M1 has a LSD additive.

FWIW- I recently had a rear locker installed and the manufacturer called for NON LSD gear oil, called for SYN 85-140- ended up with royal purple.

 

[Leandro]

You can use M1 75-90 in the TX- and the front diff(unless it's locked)- not sure about rear requirements on the 98-99 because of the factory locker. The M1 has a LSD additive.

FWIW- I recently had a rear locker installed and the manufacturer called for NON LSD gear oil, called for SYN 85-140- ended up with royal purple.

So the lsd additives in the M1 don't affect the TX?
BTW, the rear isn't locked, is limited slip

 

[abuck99]

I dont think the M1 with LSD has any impact on the TX functionality , maybe some else will confirm or argue that point. Several here use it for all 3 applications.

 

[AMGAndrew]

Use M1 75-90 Synthetic LS (limited slip) in all 3.

 

[Leandro]

Use M1 75-90 Synthetic LS (limited slip) in all 3.

thanks, that's the route i'll take.
there's a pretty good deal on Valvoline Synthetic LS, I might try that one.

 

[AMGAndrew]

Go for it. High quality name brand stuff. Can't go wrong.

 

[beachbumin]

98 lx470 here. Looking to change all 3 tomorrow and was hoping to use mobil 1 75w-90 on all 3 but wavering on using it in the rear after reading here.