Changing diff fluid. Oem or not?

Balanced my tires at the shop today and notices a couple of drops from the diff drain plug. I'm planning on changing the diff fluid and was wonder if oem fluid is worth the premium price or is there something else that you guys have used in your car. Turner has both oem and another brand for sale. Any feedback is greatly appreciated. Sponsor welcome to reply with some prices and products.

Alot of M3 owners put Royal Purple in the Diff. Depending on your driving style, either 75w90 or 75w140......Climate has some impact on weight as well. The hotter, the thicker. I live in the south, so I went with 140

non-m open's use 75-90 i use that weight with redline and have no complaints always feels good putting new fluid in. don't go oem fluid its pointless and has no benefit .. it comes down to if you want to put in redline or RP i put redline in every place i could. you should try out putting RP in the diff and redline in the tranny I'm sure you will be happy any which way

Thanks. Anybody kno about the fm booster that's supposed to be in the fluid. Do you have to add it to the redline fluid or just use the redline fluid by itself.

Also does anyone kno how much fluid it takes to fill the diff.

Originally Posted by steven747

don't go oem fluid its pointless and has no benefit ..

Please don't make blanket statements. As stated, non-M open diffs and M LSD are different and need different fluid. The FM Booster was added to reduce noise/diff whine. Many M3 owners switched to Redline or RP and noticed add'l whine after few thousand miles, fix = OEM fluid with FM Booster.

OP, your car will work fine with non-OEM fluid but I suggest you use it in case you find non-OEM fluids making un-wanted noise. Changing it once with more $ fluid is still cheaper than changing it twice with non-OEM and then OEM.

Lots of bad info in this thread.

OEM Fluid plus the FM is absolutely necessary.

Thanks. Does the oem fluid come with the FM booster mixed in already, or does it have to be added separately.

http://www.turnermotorsport.com/p-21...or-e46-m3.aspx

I bought this kit when I did my tranny and diff. The OEM fluid has the Booster mixed in already (in this kit anyways, just make sure you specify M3).

That's what i have been looking at. Has anyone used that transmission fluid and do you have any reviews or suggestions as it is not oem fluid.

Just did my diff and transmission fluid this past weekend, and to be honest neither looked *that* bad considering... 100k on the clock and I replaced the fluids with OEM. I was actually pretty impressed with how they looked.

Go oem with fm booster. The fm booster reduces the creaking noises by sinking into the clutches, so it's worth the premium price. Anything else and you will get an annoying creaking noise while turning.

Originally Posted by nyredeye21

That's what i have been looking at. Has anyone used that transmission fluid and do you have any reviews or suggestions as it is not oem fluid.

Non-OEM LT2 transmission fluid is fine, almost all of us use it. OEM LT2 comes in large drums and not all dealers will pump out 2 liters for individual sale.

I was getting that creaking sound with OEM fluid, switched to RP 75w-140 and the noise went away and has been quite nice to drive. I have put about 1000 miles since. The RP has friction modifier in it already too.

Originally Posted by mre

I was getting that creaking sound with OEM fluid, switched to RP 75w-140 and the noise went away and has been quite nice to drive. I have put about 1000 miles since. The RP has friction modifier in it already too.

Did you add the FM booster?

Originally Posted by nyredeye21

Balanced my tires at the shop today and notices a couple of drops from the diff drain plug. I'm planning on changing the diff fluid and was wonder if oem fluid is worth the premium price or is there something else that you guys have used in your car. Turner has both oem and another brand for sale. Any feedback is greatly appreciated. Sponsor welcome to reply with some prices and products.

I bought this kit from ECS Tuning. Going to do the fluid change this weekend. Hope all goes well...

Originally Posted by Rockyminator

Did you add the FM booster?

Why would I have to do that when the fluid has the additive in it already?

Originally Posted by mre

Why would I have to do that when the fluid has the additive in it already?

Because they sell the diff fluid WITHOUT FM booster too.

I bet you that creaking noise would have went away with an OEM fluid change too. Heard to many bad stories about RP to ever try it. You've only put 1000 miles on it, Id be willing to bet the noise will be back soon.

Probably would have, but not willing to pay that much for fluid. I did many forum searches and also past experience with RP products. I Machine and build custom racing engines for a living. I have used RP products in the past. The concensus on the forums was to either use RP or RL oil in the diff and tranny....NOT factory stuff as some have suggested in this thread. I know how to use the search function.

I used royal purple and had noise from my diff. Do yourself a favor and use OEM!