tranny / diff oil

E36White · 10-29-2008, 09:27 PM

hi,

im looking into flushing my tranny and diff oil within the next week ..im interested in royal purple and their website lists the following?

Quote:

BMW 1983 - 1992: inspect for color-coded label typically affixed to passenger side of the transmission

BMW Green label (SHC 630) Max-Gear 75W90

BMW Red label (DEXRON III) Synchromax

BMW no label (80W GL-4) SAE 30

BMW 1993 - 1997, all models (DEXRON III) Synchromax

my car is a 92 ...which one do i put? and how much do i need for the tranny and diff altogether?

thanks!

E36White · 12-18-2008, 03:43 PM

finally got my hands on royal purple max gear 75w90 just wanted to confirm that its the right one? 4 quarts right (tranny and diff) ?

doogee · 12-18-2008, 04:19 PM

I think you only want to put that stuff in your diff. I may be wrong.

The transmission takes ATF.

RMPMOTORS · 12-19-2008, 08:21 PM

You can use the gear oil in both the tranny and diff, but you may want to use syncromax in the tranny!!

The gear oil WILL make it stiff to shift when cold!!!

E36White · 12-19-2008, 09:48 PM

hmm..i heard the same about the tranny..how stiff would it be? that aside, is 75w90 generally better to use than syncromax ?

car has 240k with a year old clutch..shifting feels a lil notchy very few times

doogee · 12-19-2008, 10:18 PM

I'd use the gear oil in the diff and get syncromax for the tranny. I've only heard good things about it.

RMPMOTORS · 12-20-2008, 07:48 AM

The gear oil will actually protect the tranny better when warm, but WILL be stiff when first starting off when cold in the winter.

Syncromax is also great, if you want smooth shifting at all temperatures!

Rocco

richie_s999 · 12-20-2008, 08:22 AM

knotchy shifts are not usually from the gears - usually from the shiter bushings

kenmar · 12-20-2008, 09:19 AM

You WILL get notchy cold shifting if you use a heavy oil. I'm using Redline MT90 to reduce the gear rattle associated with lightweight flywheels and it's notchy in the winter when cold. It will even grind if I'm not slow and deliberate for the first few minutes.

I am using the RP GearMax 75w90 in the diff. Seems to work ok. I was originally using their 75w140 since the heavier weight seems to be recommended by BMW dealers according to bimmerforums. For me, this heavier oil seemed to cause LSD chatter on onramps and in parking lot maneuvres, so I went back to the 75w90. Prior to RP, I used Redline 75w90 in the diff for 5 years but then I developed a bad bearing and had the diff rebuilt. Not sure if that was related to the Redline and/or 75w90 weight or not.

E36White · 12-20-2008, 05:36 PM

shit loooks like im gona use watever the diff needs and exchange the rest for syncromax.

how much does the diff and tranny need each? 1.5 2.5 ?

richie_s999 · 12-20-2008, 06:01 PM

if your getting chatter in your LSD the gear oil likely does not have the LSD additive in it, you may need to add it, there are a few brands of it avalible at most parts stores. It makes a huge difference.

74w90 and 75w140 should act the same as they are both the same weight when cold. the Viscosity changes only as the oil warms up. thats why in colder weather some cars are recomended a lighter weight oil (the first number) the second number is the viscosty and should remain the same.

I agree with the people who say it feels stiff when cold but the notchy feeling is usually from bushings being cold.

E36White · 12-21-2008, 03:58 PM

i dont have LSD so there is no chatter of any sort .. the diff is whatever came on the 92 325i.

shifting is randomly notchy sometimes i was told it could be the oil ..if it were the bushings then it'd be constantly notchy no?

i figured i'd change the diff oil while im at it ... ive only had the car since june so i dont know when that was last done.. preemptive maintenance i guess

any harm in doing that?

doogee · 12-21-2008, 07:07 PM

Quote:

Originally Posted by E36White

i dont have LSD so there is no chatter of any sort .. the diff is whatever came on the 92 325i.

shifting is randomly notchy sometimes i was told it could be the oil ..if it were the bushings then it'd be constantly notchy no?

i figured i'd change the diff oil while im at it ... ive only had the car since june so i dont know when that was last done.. preemptive maintenance i guess

any harm in doing that?

Of course there is no harm in preventative maintenance

May as well do both since oil is so cheap.

E36White · 12-21-2008, 07:37 PM

^i duno about cheap its $20 a quart lol... hey cheap and bmw cant be in the same sentence tho

wat kind headlights do u have dogee? and wats in them?

doogee · 12-21-2008, 07:54 PM

Depo's with Predator Chromiums 6000k

6000k 55w lows and fogs too. They really light up the road.

Got everything from DDM