Trans and Diff Oil Question

[torqueflight]

I want to change out my trans and diff oil. I was thinking of running Redline in both.

Whats the most common weight for the e30? And do I need a modifier for the LSD?

Thanks,
Matt

[jlevie]

Redline is a good choice for those. Use MTL in the transmission and 75w90 in the differential. Redline 75w90 includes friction modifiers.

[MR 325]

I would use the 75w90 in both the diff and trans. Also, we still add the Redline friction modifier [half bottle] to customer vehicles even when filling the diff with Redline gear oil.

[torqueflight]

Thanks! ^ What the difference if I don't put the extra modifier in?

Thanks
M

[tonytony]

you might get more chattering from the diff

[TrentW]

I'm slightly confused here. I used Red Line 75w90 in my lsd when I changed it a year and a half ago and no problems. Now I see they offer a 75w90NS for closed diffs. I'm changing the diff fluid in the wife's car which is also lsd. Should I change both using the NS version?

[Van Westervelt]

I use Swepco in my transmissions. Redline 75w90 in the diffs.

[TrentW]

do you have lsd? And if so, 75w90NS or just the 75w90? That's where I'm confused, as it seems the NS version is made specifically for the limited slip diffs.

[DJB]

You must use a GL-4 fluid, not GL-5, in the Getrag 260 transmission.

That means Redline MTL or MT-90, not the other Redline gear oils.

The diff uses GL-5 fluid. It's easy to find good GL-5 fluids.

[Jean]

How does Mobil 1 70w90 compare to Redline MTL?

[bcrdukes]

do you have lsd? And if so, 75w90NS or just the 75w90? That's where I'm confused, as it seems the NS version is made specifically for the limited slip diffs.

Prior to owning my current E30, I did extensive research on various transmission fluids for my Alfa Romeo Spider. The Redline designation, "NS" means "non-slip" which translates to "without friction modifiers" and was appropriate for the transmission on the Spider.

After doing some more homework for the E30, I've used Redline MTL for the transmission and 75W90 for both my stock open diff and 3.73 LSD diff. It seems to be the choice for most E30 owners. However, due to the age of our cars, I would recommend against Redline as it is a synthetic and will leak through the seals as per my unfortunate experiences. If you can stick to $$$stock BMW$$$ fluids, go for it or as cheap insurance, change out any seals prior to using Redline or the synthetic gear oil of your choice.

In regards to differential chatter, mostly pertaining to LSD differentials, using 75W90 has been fine for the most part. The E30 is my daily driver so I'm not mashing the car like crazy to notice any obvious LSD chatter however, YMMV.

[stumble_t]

I spoke to a BMW service tech at the dealer yesterday and he told me all BMW oils are supplied by castrol and to use Castrol 75-90 in the diff. When I asked about friction additives he said all they are are detergents and just use "regular" oil and that I could put some in (additive) if I get any chatter. Does this sound accurate?

[REVHARD05]

You must use a GL-4 fluid, not GL-5, in the Getrag 260 transmission.

That means Redline MTL or MT-90, not the other Redline gear oils.

The diff uses GL-5 fluid. It's easy to find good GL-5 fluids.

what is the standard volume that the getrag 260 holds? and what is the difference in the gl 5 and gl 4? thanks r3v

[red325i]

1.25L for the GETRAG 260....which is also about the time it comes out the fill hole..