Feedback about Redline 75w140 for the differential

[elim11]

Originally Posted by Hujan

I am curious how you gents are pouring the Redline in the diff. The OEM stuff comes in a bottle that allows you to "inject" it into the pumpkin if that makes sense. But the Redline bottle is difficult to fit up in there. I had to use a Mity-Vac to get it in there. Any trick I am missing?

Also, are you guys replacing the fill/drain plugs? I think they are single use.

I saved a couple of the OEM bottles and i refill it with the redline.

[drwankel]

I used a gear oil pump, and yes I did replace the drain plugs. They look like single use plugs due to the orings.

[nholmes]

Originally Posted by Hujan

I am curious how you gents are pouring the Redline in the diff. The OEM stuff comes in a bottle that allows you to "inject" it into the pumpkin if that makes sense. But the Redline bottle is difficult to fit up in there. I had to use a Mity-Vac to get it in there. Any trick I am missing?

Also, are you guys replacing the fill/drain plugs? I think they are single use.

http://www.ebay.com/itm/Plews-55-001...-/141761720473

[Hujan]

Originally Posted by nholmes

http://www.ebay.com/itm/Plews-55-001...-/141761720473

Awesome! That's fantastic! Great, great find.

[nholmes]

Originally Posted by Hujan

Awesome! That's fantastic! Great, great find.

np

I have one for used oil, one for transmission fluid and one for diff fluid

[dparm]

Originally Posted by Hujan

I am curious how you gents are pouring the Redline in the diff. The OEM stuff comes in a bottle that allows you to "inject" it into the pumpkin if that makes sense. But the Redline bottle is difficult to fit up in there. I had to use a Mity-Vac to get it in there. Any trick I am missing?

Also, are you guys replacing the fill/drain plugs? I think they are single use.

Any auto parts store will send a cheap hand pump for < $20. Can easily be reused for tons of things around the house, too.

[kyoo]

jeez - is there a reason 75w140 is required? car will be used for autox and HPDEs, was thinking about using 75w110. Not sure what is special about this diff compared to others that it needs 75w140. I think RL's 75w110 is a little thicker than most also

seems Turner's project M3 used 75w110:

http://www.bimmerworld.com/E92-M3-Track-Project-Car/

[dparm]

Originally Posted by kyoo

jeez - is there a reason 75w140 is required? car will be used for autox and HPDEs, was thinking about using 75w110. Not sure what is special about this diff compared to others that it needs 75w140. I think RL's 75w110 is a little thicker than most also

seems Turner's project M3 used 75w110:

http://www.bimmerworld.com/E92-M3-Track-Project-Car/

The reason 75w140 is required is because BMW says so. They don't just arbitrarily select a viscosity. If you feel like you know better than BMW and GKN (who builds the LSD), and you have spare cash if it blows up, feel free to run 75w110 or whatever. And FWIW, the E46 used the same unit and required 75w140 even back then.

The fact that you are going to be using it for the track is even more reason to run a stout fluid like 75w140.

[kyoo]

Originally Posted by dparm

The reason 75w140 is required is because BMW says so. They don't just arbitrarily select a viscosity. If you feel like you know better than BMW and GKN (who builds the LSD), and you have spare cash if it blows up, feel free to run 75w110 or whatever. And FWIW, the E46 used the same unit and required 75w140 even back then.

The fact that you are going to be using it for the track is even more reason to run a stout fluid like 75w140.

that's more or less what i thought, guess i'm coming from way too much of a tuner culture. i'll do a 1yr UOA with the 75w110, noting usage, mileage, autox runs, and track days/minutes, and repost here with the UOA afterwards.

I've seen a lot of built cars that run the thickest fluids possible because it's the safe/easy button to "prevent something from going wrong," - and doing other things, like sticking with the factory fill because "they know what they're doing," - enough to the point that I ran virgin oil samples on all the common diff fluids ran (https://qlmotorsport.com/2016/02/15/...0345-oil-test/). Turns out there's nothing special about those factory fills, sometimes it's just to quiet things down. a few cars i've seen even that come with clutch diffs have the plates deactivated from the factory just to shut them up.

hopefully it goes well. if i notice anything seem off early i'll flush in 75w140.

[dparm]

"As thin as possible but as thick as necessary"

You are correct that a thicker fluid is not always needed and creates problems of its own, but why someone would go against the OEM recommendation [on a stock car] that has worked fine for tens of thousands of units for tens of thousands of miles each is baffling.

A single UOA after 1 year will be of limited use. The whole point is to establish a baseline and look for deviations from that.

[kyoo]

Originally Posted by dparm

"As thin as possible but as thick as necessary"

You are correct that a thicker fluid is not always needed and creates problems of its own, but why someone would go against the OEM recommendation [on a stock car] that has worked fine for tens of thousands of units for tens of thousands of miles each is baffling.

A single UOA after 1 year will be of limited use. The whole point is to establish a baseline and look for deviations from that.

well just for me then. i change the trans & gear oil on my evo, which sees similar use, annually. will report back in case anyone's curious (to clarify, 1 year with 75w110, 1 year of similar use, noting major contributors, with 75w140), thanks for the input!

i also sent bimmerworld a msg to see why they chose the red line 75w110 in their project track car also. not sure if i'll hear back from them, but curious their reasoning.

[kyoo]

FWIW, here's a response from Bimmerworld on why they chose to go with a 75w110 on their track car:

Our main reasoning is heat. A 75w140 will build up and hold heat much more than a 110, and the biggest killer of differentials is exactly that; heat. With that said, if the car will not see track time where heat becomes an issue, 75w140 is perfectly fine for the differential. If you plan on taking the car to the track, we run 75w110 in the differential and 15w50 in the engine. Both of these decisions are made because the slighter lighter weight allows for the oil to shed heat quicker, prolonging the life of the oil and the components, while still providing more than adequate protection when a high quality fluid is used such as Red Line.

[dparm]

Originally Posted by kyoo

FWIW, here's a response from Bimmerworld on why they chose to go with a 75w110 on their track car:

Correct, a thicker fluid will hold heat longer but also thin out less. Are they using that as an actual race car, meaning continuous lapping of 2+ hours?

For a car going to HPDE and doing 20 minute sessions and then cooling off for an hour or more, the heat thing is less of an issue.

[kyoo]

Originally Posted by dparm

Correct, a thicker fluid will hold heat longer but also thin out less. Are they using that as an actual race car, meaning continuous lapping of 2+ hours?

For a car going to HPDE and doing 20 minute sessions and then cooling off for an hour or more, the heat thing is less of an issue.

It's listed as their "street/track" car, which obviously could mean anything, but I assume that means daily driveable + autox/hpde, not continuous lapping/only used on track. I believe that car may have changed into something else, but that was the mentality relayed to me for that purpose.

Anyway, we'll see how it goes for my specific use.