automatic differential fluid help/question

[cpandrewschmidt]

hi all,
going to change diff fluid on a 4.10 325i automatic. non lsd. I have a little chatter back there and hoping this might help with since I have no idea when if ever it might have been changed.

Looking at Red Line 57904 (75W90) Synthetic Gear Oil

http://www.amazon.com/Red-Line-57904-Synthetic-Oil/dp/B000CPCBF0/ref=sr_1_2?ie=UTF8&qid=1464226818&sr=8-2&keywords=75W-90+fluid

or I see people talking about Redline MTL. Is that for manual trans only?

http://www.amazon.com/Red-Line-50304-Transmission-Transaxle/dp/B000CPCBEQ/ref=sr_1_4?ie=UTF8&qid=1464227034&sr=8-4&keywords=75W-90+fluid

Don't know what the difference is or which one I need. Any help appreciated.

Andrew

[roguetoaster]

You're wasting your money on Red Line as some off-the-shelf Valvoline or similar from the local auto parts place will do just fine for the demands of an automatic equipped car.

MTL=manual transmission lube.

[TobyB]

Chatter? As in, the diff's having conversations with the subframe?

Whining is much more common, and the bad news is that once it's started,
it's usually already damaged somewhat. My 'not- fix' is to go to a heavier
weight oil, like a 90-140 or something.

And I do agree, for a street car where it'll be changed every 30k, standard decent
quality gear oil is just fine.
But if you plan to forget to change it for another 60-90k, spring for the synthetic.
You're not wasting THAT much money.
It does take 1.5 qts or so.

t

[ELVA164]

I found the capacity of my diff to be just under 2 quarts when I last changed it, for what it's worth.

[TobyB]

:devil: I think you put too much in!

But then, if it doesn't spit out the vent, it won't do any harm...

t