Red line MT 90 in power loc diferential

E-Type
1

Alright to use Red line MT 90 in power loc diff
Right or wrong

2

Red Line is a reputable company. What do they say about use of their product in a power loc?

3

Not an expert - but I think you want something with friction modifiers, like this:

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4

No offense to anyone, but @Dick_Maury is the only guy Iā€™d trust with this question. Just my .02.

5

I used ā€œValvoline Synpower Full Synthetic For Limited Slip Differentialsā€.

6

Same here, although I had some clutch chatter in the limited slip and had to add a separate friction modifier. All good now.

7

Always good to look at the website for the people that make the oil: https://www.redlineoil.com/75w110-gl-5-gear-oil This already has the friction modifier additive built in and recommended for Limited Slip. The MT90 is OK for diffs but additive might have to be added.

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8

I had that early on. I called Dick, he sold me the diff, and he told me to go out to an empty parking lot and make tight turns to ā€œbreak in the diff clutch packsā€ My words, not his. I did and between that and normal driving the noise went away.

Dick: Please correct me if I misrepresented what you told me.

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9

How about that? Your opinion is as good as Dickā€™s!
:wink:

10

Iā€™m not as smart as the teacherā€¦ I just paid attention in class.

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11

Unless Iā€™m missing something, is MT90 not a gearbox oil?

You should be using a specific LSD diff oil.

I use Castrol Axle 90 Limited Slip Diff Oil.

12

Dick, so using an oil for an LSD as you state, will that void the need for the additive sold by the usuals ?

13

The additive is a friction modifier. Oils specified for limited slip diffs usually contain this so no need for additional. I do not recommend adding any additive unless needed. If the diff is quiet in tight corners, leave it alone.One other note: make sure somewhere it says Hypoid specs. Most of the better ones are but good to check anyway.

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14

Had the dif re geared to 3.07 27 years ago and
Never used it till 3 years ago. Canā€™t say for sure but the car feels like it accelerates faster with the 3.07 gears. Wish I would have went to 2.88
1 st gear is still to low to use full throttle reaching red line too quickly. Going to change the diff oil
At 2000 miles and your info pointed me in the right direction. Thanks

15

To the original questionā€¦

RedLine MT90 is the wrong oil for the diff. It is for the gearbox. It is GL-4 gear oil.

RedLine 75W90 is for the diff (posi or otherwise). It is a Gl-5+ Hypoid gear oil. It contains an additive for limited slip diffs.

I am no expert on lubricants. I am merely reading the labels on the bottles in front of me.

I have used each in their places for about 5 years, with quite acceptable results.

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16

Now thereā€™s a concept! Exactly correct. :grinning:

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17

As my wife once said after a tough day at the lab - ā€˜I either need a bottle in front of me or a frontal lobotomyā€™.

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18

Been doing exactly the same for about 5 / 6 years without any issues.