Changing out my diff and tranny fluids

[tekmoe]

Did I buy the right stuff?



My warranty is almost up and I plan on switching out the current OEM fluids with Royal Purple. According to the service records, the last time it was changed was at the 1200 mile service.

I about damn-near had a heart attack when I found out how much the OEM fluids cost. I seriously doubt they are any better than any full syn on the market. But hey, if people will pay for it, then that's what they are going to charge so more power to 'em.

[The HACK]

I don't know if it really matters or not, but the Royal Purple equivalent to BMW's MTL-LT-2 is Max-Gear. Synchromax only meets or is equivalent MTL-LT-1.

Personally I'd have gone BMW OEM and buy it from Turner:

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

Sure, it's expensive, but these diffs and transmissions seems to be somewhat on the sensitive side to what is used.

[Caddyshk]

Originally Posted by tekmoe

Did I buy the right stuff?



My warranty is almost up and I plan on switching out the current OEM fluids with Royal Purple. According to the service records, the last time it was changed was at the 1200 mile service.

I about damn-near had a heart attack when I found out how much the OEM fluids cost. I seriously doubt they are any better than any full syn on the market. But hey, if people will pay for it, then that's what they are going to charge so more power to 'em.

Don't screw with the Diff. OE only. RP Synchromax is what many of us have switched to in the transmission.

[wrh3]

Originally Posted by Caddyshk

Don't screw with the Diff. OE only. RP Synchromax is what many of us have switched to in the transmission.

x2, OE for the diff, Synchromax for the transmission

[tekmoe]

Unless I am mistaken, we share the same differential with the E46 M3. I've read numerous posts where the M3 crowd is using Royal Purple in both the diff and tranny with no issues at all. I've also seen a few guys on here say the same thing. I respect your opinions to stick with OE fluids. However, having used aftermarket oils in nearly every car and motorcycle I have ever owned, I'm very hesitant to pay the outrageously jacked up prices that BMW is asking for their fluids.

I will do some more research on this subject and report back with my findings.

[Caddyshk]

Originally Posted by tekmoe

Unless I am mistaken, we share the same differential with the E46 M3. I've read numerous posts where the M3 crowd is using Royal Purple in both the diff and tranny with no issues at all. I've also seen a few guys on here say the same thing. I respect your opinions to stick with OE fluids. However, having used aftermarket oils in nearly every car and motorcycle I have ever owned, I'm very hesitant to pay the outrageously jacked up prices that BMW is asking for their fluids.

I will do some more research on this subject and report back with my findings.

Search a little deeper - problems with diffs using RP.

[mfanatic325]

Originally Posted by Caddyshk

Search a little deeper - problems with diffs using RP.

The race shop I went to for rebuilding and installing my differential (3.91 ratio) said they've tried all sorts of fluids on their own personal track cars and found that OE diff fluid was the best for stock LSD. They told me that they experienced slight NVH with every fluid except for OE and was just as skeptical and reluctant on spending the money, but that's just what they've found--through years of personal experience--to be the best as far as stock differential goes.

I've no comment about RP Synchromax for the tranny fluid, but it seems the majority here on the forums are happy with it. Therefore, I'm probably going to flush mine out with Synchromax too once my warranty is up

Originally Posted by tekmoe

I'm very hesitant to pay the outrageously jacked up prices that BMW is asking for their fluids.

I just recently did an oil change out of pocket (in-between service intervals) because I've been tracking my car a lot and wanted the additional peace of mind. From Tischer BMW, the M3forum specials page came to a total of $90 shipped for 6 quarts of Castrol 10W60 and an oil filter kit. This is not far from the cost of a differential flush, which is 2 bottles, and comes to a total of just over $100. Honestly, if the oil changes cost this much, I figure why not spend on differential fluid as well? You won't need to flush the diff out nearly as much anyhow.

[tekmoe]

Originally Posted by mfanatic325

The race shop I went to for rebuilding and installing my differential (3.91 ratio) said they've tried all sorts of fluids on their own personal track cars and found that OE diff fluid was the best for stock LSD. They told me that they experienced slight NVH with every fluid except for OE and was just as skeptical and reluctant on spending the money, but that's just what they've found--through years of personal experience--to be the best as far as stock differential goes.

I've no comment about RP Synchromax for the tranny fluid, but it seems the majority here on the forums are happy with it. Therefore, I'm probably going to flush mine out with Synchromax too once my warranty is up


I just recently did an oil change out of pocket (in-between service intervals) because I've been tracking my car a lot and wanted the additional peace of mind. From Tischer BMW, the M3forum specials page came to a total of $90 shipped for 6 quarts of Castrol 10W60 and an oil filter kit. This is not far from the cost of a differential flush, which is 2 bottles, and comes to a total of just over $100. Honestly, if the oil changes cost this much, I figure why not spend on differential fluid as well? You won't need to flush the diff out nearly as much anyhow.

Interesting. Thanks for the in-depth details.

I too changed my engine oil even though the service indicator still said 6,000 to go. I did the same as you and bought the kit from Tischer. You are also right about the diff not needing to be changed nearly as often. Every 20k-30k is probably enough.

I'll give it some more thought. I can easily return this stuff and get the OE if need be.

[Caddyshk]

Originally Posted by mfanatic325

The race shop I went to for rebuilding and installing my differential (3.91 ratio) said they've tried all sorts of fluids on their own personal track cars and found that OE diff fluid was the best for stock LSD. They told me that they experienced slight NVH with every fluid except for OE and was just as skeptical and reluctant on spending the money, but that's just what they've found--through years of personal experience--to be the best as far as stock differential goes.

I've no comment about RP Synchromax for the tranny fluid, but it seems the majority here on the forums are happy with it. Therefore, I'm probably going to flush mine out with Synchromax too once my warranty is up


I just recently did an oil change out of pocket (in-between service intervals) because I've been tracking my car a lot and wanted the additional peace of mind. From Tischer BMW, the M3forum specials page came to a total of $90 shipped for 6 quarts of Castrol 10W60 and an oil filter kit. This is not far from the cost of a differential flush, which is 2 bottles, and comes to a total of just over $100. Honestly, if the oil changes cost this much, I figure why not spend on differential fluid as well? You won't need to flush the diff out nearly as much anyhow.

Actually just over 2 bottles...

[mfanatic325]

Originally Posted by Caddyshk

Actually just over 2 bottles...

For a full flush right? I recall that a drain and fill only requires one bottle or something? Don't quote me on that. Just going off the top of my head, as I haven't done the fluid swap with my own two hands just yet =P

[kennef]

OE for the diff, motul gear FF LSD Type 2 for the tranny. so far so good.

[Caddyshk]

Originally Posted by mfanatic325

For a full flush right? I recall that a drain and fill only requires one bottle or something? Don't quote me on that. Just going off the top of my head, as I haven't done the fluid swap with my own two hands just yet =P

IIRC - 1.1L - had to purchase three 500ml bottles... The 3 pack.

[Z4Murder]

Originally Posted by Caddyshk

IIRC - 1.1L - had to purchase three 500ml bottles... The 3 pack.

correct. i am doing this in the near future. you need (3) .5 liter bottles. bought off tischer for $10.10 each for the saf-xj. it says 1 liter, but they are actually .5 liter bottles

[tekmoe]

Originally Posted by Z4Murder

correct. i am doing this in the near future. you need (3) .5 liter bottles. bought off tischer for $10.10 each for the saf-xj. it says 1 liter, but they are actually .5 liter bottles

Wow, how long ago was that? Not sure if you've looked lately but they now cost $45 each!

[mfanatic325]

lol that's what I thought. Cause my race shop charged me for two or three bottles, totalling just over $100 for the fluid. They threw the labor in free of charge since they recommended OE for diff, and it was very expensive.

[Z4Murder]

Originally Posted by tekmoe

Wow, how long ago was that? Not sure if you've looked lately but they now cost $45 each!

bought it yesterday... are you sure you're not looking at the saf-xj+ fm booster which is much more expensive?

[tekmoe]

Originally Posted by Z4Murder

bought it yesterday... are you sure you're not looking at the saf-xj+ fm booster which is much more expensive?

You are right. But why are you running the fluid without the FM booster? No grinding?

[jmillet]

Originally Posted by tekmoe

You are right. But why are you running the fluid without the FM booster? No grinding?

My Z4MC sees many track days a season and I run the standard SAF-XJ without friction modifier booster and experence no grinding.
Don't forget to replace the drain plugs as they are one-use O-ring type plugs.

[tekmoe]

Originally Posted by jmillet

My Z4MC sees many track days a season and I run the standard SAF-XJ without friction modifier booster and experence no grinding.
Don't forget to replace the drain plugs as they are one-use O-ring type plugs.

Nice. That would actually be cheaper than the Royal Purple if they cost 10 bucks a pop. I think I'll go that route instead. Thanks for the tip!

BTW, I'm having a hell of a time finding a 14mm hex anywhere in town. Biggest I have found is 12mm. Probably going to order one online.

[jmillet]

Originally Posted by tekmoe

Nice. That would actually be cheaper than the Royal Purple if they cost 10 bucks a pop. I think I'll go that route instead. Thanks for the tip!

BTW, I'm having a hell of a time finding a 14mm hex anywhere in town. Biggest I have found is 12mm. Probably going to order one online.

Try Sears:
http://www.sears.com/shc/s/p_10153_1...=1298152938589
It's a 1/2 " drive but the Z4M diff plugs are on the passenger side of the housing so access isn't an issue.

[franco209]

Just received mine from Amazon. $2.76 + shipping.
http://www.amazon.com/gp/product/B000UVP0DG

[mfanatic325]

Holy hell! I didn't know that the diff fluid without friction modifier was that much cheaper. I used friction modifier in my MR2 as well though, which also only had a viscous LSD from the factory.