[mpwr247]

Bought e39 2001 Lemans blue. Will post pics when the car gets here. I want change out all fluids engine, tranny, diff. Searched the forum found how to get this done. The engine will get oem fluid. The tanny, diff want change with royal purple. Here's the advice I need. Should I get oem fluids or royal purple is better because I see a lot of owners use this oil, but they they folow up with this remark that gets me thinking. Change to royal purple xxxxxx of miles ago still running good. Please advice me on this question. :confused2

 

[gherardini]

TWS is great for engine oil, just expensive. You can use Mobil1 0/40 if you wish to save $5 a qt.

RP is great for transmission. use it and don't think twice about it.

Not sure about diff... Need to do mine as well, so I'll be looking for what's recommended here.

 

[josiahg52]

Royal Purple now has years of success in our car's transmission and differential. The main concern in the beginning was its suitablity in the transmission as a variant of our Getrag was used in the Supra and apparently that variant used a plastic that were not fully compatible with the fluid. Actually, come tho think of it, this incompatibility may have been with a Red Line product. Well, in any case, Royal Purple Synchromax is an excellent choice for our transmissions and the 75W140 is perfectly fine in the differential. My car used it for about 80k miles and I plan to switch to them in my next M5.

-Josiah

 

[mpwr247]

Royal Purple now has years of success in our car's transmission and differential. The main concern in the beginning was its suitablity in the transmission as a variant of our Getrag was used in the Supra and apparently that variant used a plastic that were not fully compatible with the fluid. Actually, come tho think of it, this incompatibility may have been with a Red Line product. Well, in any case, Royal Purple Synchromax is an excellent choice for our transmissions and the 75W140 is perfectly fine in the differential. My car used it for about 80k miles and I plan to switch to them in my next M5.

-Josiah

Glad to hear that you used for 80k with no problems THanks Josiah.

 

[gherardini]

Glad to hear that you used for 80k with no problems THanks Josiah.

+1!

 

[Beemer Guy]

RP is probably just fine, but unless you have a strong reason for using it, I'd personally stick with the OE manufacturer for fluids.

Or you could just go with whichever is cheaper.