Redline 75/140NS Diff Oil + LSD Friction Modifier

[funcrew]

The 3.73LSD on my cabrio was working great with 64K on it since new, but I was looking for even more lockup and the 20-year-old oil needed changing anyway for maintenance.

I drained the diff and filled it with Redline 75/140NS, which does NOT have the LSD friction modifier pre-added. The Redline instructions say, in summary, to slowly add friction modifier until you get down to a level of lockup that you can live with.



Per Redline instructions, I added one ounce of LSD friction modifier.



Went for a test drive and the LSD ground and chattered moderately. Again per Redline instructions, I added one more ounce of friction modifier and test drove again. This time it was perfect; nice and smooth; no grinding, no chattering, but the LSD is so tight that it squeals a bit on slow turns with only the slightest throttle pressure. The LSD feels great, and it's easier to kick the tail out.

Highly recommended.

BTW Redline says that race cars often don't use any friction modifier at all; they live with the harshness to get higher lockup.

[tonytony]

i always assumed that the friction modifier made it have better lock up, so what i'm getting is that all it does is make it more smooth?

[kenika65]

hum ok good info.

[funcrew]

The "NS" version of the product does not have friction modifier & provides the greatest lockup, but also the most chatter.

The regular version of the product has plenty of friction modifier & gives less lockup but more smoothness.

[tonytony]

i see, gotcha. now it all makes since that my diff was having a chatfest when i was using the redline shockproof. driving around parkling lots was really annoying and embarassing, especially having a lady in the car. "my car isn't falling apart i swear"

[funcrew]

UPDATE: Not a fault of the product, but - My diff seals for the output shafts were seeping just a smidge. Once the synthetic oil went in, they let go in just a few months. I'm now a believer (I ignored the R3V old-timers' warnings) that synth fluids and 20-year-old rubber seals don't work well together. Same thing happened to the transmission (now fixed) and oil cooler thermostat (now fixed).

If I had another E30, I would just run old-style dinosaur oil in everything unless I changed the seals first.

[SamE30e]

So it would be a good idea to change the seals before adding this?

[funcrew]

So it would be a good idea to change the seals before adding this?

If your diff has no leaks at all - if the output flanges are totally clean on the bottom, you might try running the synthetic fluid with the old seals. But keep looking for signs of seepage. There's a nice kit for diff seals and bushing, including 2 quarts of redline here:

http://www.harrisonmotorsports.com/shop/index.php?main_page=product_info&products_id=907

It's the redline fluid that already has the friction modifier, but unless you're racing the car, I think that's fine. The re-seal package is a great deal.

[DiscoE30]

Updated link for Red Line Limited-Slip Friction Modifier

BTW, Harrison Motorsports updated their website and the link to Diff Reseal is

http://www.harrisonmotorsports.com/p...al-reseal-kit/

The link to Parts & Product is now http://www.harrisonmotorsports.com/parts/

Hope that helps.

[willymori]

hello,
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[ThatM20Guy]

LOL at the spam resurrecting a dead thread