Redline ATF D6 or D4 for manual tranny?

BigRussia · 12-26-2015, 09:42 AM

I'm going to change my 6mt tranny fluid and after researching decided to go with Reline ATF D6. But I've also seen some ppl recommend or use the D4. I read about both on Redline's site but couldn't figure the differences or benefits between them. Which one should I go with living in Miami Fl where the temp rarely ever gets below 75 (its 81 this morning) and is usually steamy hot?

Oh and how many quarts should I buy? I was thinking 3 should be enough?

Thanks!

MightyMouseTech · 12-26-2015, 10:29 AM

D4 is a little heavier than D6, so probably a little better in warm climates.

Although, being in Florida I would probably recommend MTL instead. I use MTL in my summer car, and D4 in my winter car.

Tranny takes JUST under 2L, so if you don't spill any, you can get away with 2. Maybe get three just in case.

BigRussia · 12-27-2015, 12:36 PM

Quote:

Originally Posted by MightyMouseTech

D4 is a little heavier than D6, so probably a little better in warm climates.

Although, being in Florida I would probably recommend MTL instead. I use MTL in my summer car, and D4 in my winter car.

Tranny takes JUST under 2L, so if you don't spill any, you can get away with 2. Maybe get three just in case.

Cool thanks for the info! I wasn't even aware of the MTL, seems like its a little thicker than the D4.

MightyMouseTech · 12-27-2015, 12:52 PM

Quote:

Originally Posted by BigRussia

Quote:

Originally Posted by MightyMouseTech

D4 is a little heavier than D6, so probably a little better in warm climates.

Although, being in Florida I would probably recommend MTL instead. I use MTL in my summer car, and D4 in my winter car.

Tranny takes JUST under 2L, so if you don't spill any, you can get away with 2. Maybe get three just in case.

Cool thanks for the info! I wasn't even aware of the MTL, seems like its a little thicker than the D4.

Yes, the MTL is a little thicker. Tried a bunch of different fluids in my 1er, the MTL is my favourite. A little thick for below freezing temps, that is why I use D4 in my winter car, which I find is a little thin when above 20 C or so.

Although, don't really like the feel of D4 in winter car, may put MTL in that one as well and take it easy when it is really cold.

MN.BIMMER · 03-25-2019, 10:17 AM

Bringing this one back up, as it's time to change the trans fluid and I live in MN where we can see temps down to -20F during winter.

For a daily driven, garage kept car, would D4 still be the best bet?

NorthernDancer · 03-25-2019, 11:12 AM

You can't go wrong with either D4 or D6 however I think I would go with D6 due to your/our very cold winters.

MN.BIMMER · 03-25-2019, 11:40 AM

Gotcha, it seems pretty divided on whether people use D4 or D6, especially in colder climates. Guess I'll go with D4 at first and report my findings!

JimD · 03-26-2019, 08:20 AM

I am in a pretty warm climate but I've used MTL and D4 and I think I like the thicker MTL better. With the thinner D4 the transmission doesn't seem as smooth. Both work fine, however.

I mention this because I think the same may be true for D4 versus D6 in a cold climate. D6 will feel a bit more mechanical and shift better before the transmission warms up. D4 will feel a bit smoother but be a little stiff before the transmission warms up. Depends a bit on what you like.

Thunderguts · 04-02-2019, 12:37 PM

The best oil depends on many different factors from the age/condition of your synchros to your climate. No one can tell you what will work best in your car. I tried 4 different oils and finally decided that D4 works the best in my car. I have the M short shift kit and live in TX.

Worst case scenario, you're out $25 and an hour your time. Try a couple different oils and see which works best.

12-26-2015, 09:42 AM	#1
BigRussia Captain 152 Rep 984 Posts Drives: 04 M3 Join Date: Nov 2014 Location: SFL iTrader: (5)	Redline ATF D6 or D4 for manual tranny? I'm going to change my 6mt tranny fluid and after researching decided to go with Reline ATF D6. But I've also seen some ppl recommend or use the D4. I read about both on Redline's site but couldn't figure the differences or benefits between them. Which one should I go with living in Miami Fl where the temp rarely ever gets below 75 (its 81 this morning) and is usually steamy hot? Oh and how many quarts should I buy? I was thinking 3 should be enough? Thanks! __________________ 2004E46M36MTCBCinn 'Clubsport'
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12-26-2015, 10:29 AM	#2
MightyMouseTech Major General 4338 Rep 6,196 Posts Drives: 13 135i 6MT LeMans Blue MSport Join Date: Feb 2013 Location: Ottawa, Canada iTrader: (0)	D4 is a little heavier than D6, so probably a little better in warm climates. Although, being in Florida I would probably recommend MTL instead. I use MTL in my summer car, and D4 in my winter car. Tranny takes JUST under 2L, so if you don't spill any, you can get away with 2. Maybe get three just in case.
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03-25-2019, 10:17 AM	#5
MN.BIMMER No Cop No Stop 68 Rep 160 Posts Drives: 2012 BMW 135i Join Date: Jan 2019 Location: MPLS, MN iTrader: (0)	Bringing this one back up, as it's time to change the trans fluid and I live in MN where we can see temps down to -20F during winter. For a daily driven, garage kept car, would D4 still be the best bet? __________________ Current Garage! 2012 BMW 135i - 6MT w/ OEM 550i clutch & MFactory LWFW, Pure Stage 1, MFactory LSD, VRSF Catless Downpipe, JB4 w/ MHD BEF
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03-25-2019, 11:12 AM	#6
NorthernDancer Colonel 848 Rep 2,276 Posts Drives: 08 Sedona 128 & 06 330xiT 6MT Join Date: Apr 2011 Location: Ottawa On Canada iTrader: (3)	You can't go wrong with either D4 or D6 however I think I would go with D6 due to your/our very cold winters.
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03-25-2019, 11:40 AM	#7
MN.BIMMER No Cop No Stop 68 Rep 160 Posts Drives: 2012 BMW 135i Join Date: Jan 2019 Location: MPLS, MN iTrader: (0)	Gotcha, it seems pretty divided on whether people use D4 or D6, especially in colder climates. Guess I'll go with D4 at first and report my findings! __________________ Current Garage! 2012 BMW 135i - 6MT w/ OEM 550i clutch & MFactory LWFW, Pure Stage 1, MFactory LSD, VRSF Catless Downpipe, JB4 w/ MHD BEF
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03-26-2019, 08:20 AM	#8
JimD Brigadier General 368 Rep 3,547 Posts Drives: 128i convertible Join Date: Apr 2009 Location: Lexington, SC iTrader: (0)	I am in a pretty warm climate but I've used MTL and D4 and I think I like the thicker MTL better. With the thinner D4 the transmission doesn't seem as smooth. Both work fine, however. I mention this because I think the same may be true for D4 versus D6 in a cold climate. D6 will feel a bit more mechanical and shift better before the transmission warms up. D4 will feel a bit smoother but be a little stiff before the transmission warms up. Depends a bit on what you like. __________________ 128i Convertible, MT, Alpine White, Black Top, Taupe Leatherette, Walnut, Sport Ordered 5/22/09, Completed 6/4/09, At Port 6/9/09, On the Georgia Highway 6/13/09, Ship Arrived Charleston 6/24/09 at 10pm, PCD 7/21/09
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04-02-2019, 12:37 PM	#9
Thunderguts Captain 781 Rep 999 Posts Drives: 2009 128i Sport MT Join Date: Jul 2018 Location: DFW iTrader: (0)	The best oil depends on many different factors from the age/condition of your synchros to your climate. No one can tell you what will work best in your car. I tried 4 different oils and finally decided that D4 works the best in my car. I have the M short shift kit and live in TX. Worst case scenario, you're out $25 and an hour your time. Try a couple different oils and see which works best.
	Appreciate 0 Quote