[dc5_champ88]

D4 ATF it is then!

[Penn999]

Originally Posted by dzenno

I'm actually using the UUC cocktail:

http://www.uucmotorwerks.com/html_te...nny_rattle.htm

I'll probably go with pure D4 ATF next though as I think it'll be better for, on average, colder climates such as Canada

The owner of UUC(Rob) uses the anti-friction additive(the link I posted) in his personal car.

[JoosyJoos]

Originally Posted by Penn999

The owner of UUC(Rob) uses the anti-friction additive(the link I posted) in his personal car.

I don't trust UUC products at all any more after hanging out at Road Atlanta with a few guys. Just saying... read up on bimmerforums if you wanna learn more or ask the United BMW of Roswell guys for some feedback.

[Penn999]

Originally Posted by JoosyJoos

I don't trust UUC products at all any more after hanging out at Road Atlanta with a few guys. Just saying... read up on bimmerforums if you wanna learn more or ask the United BMW of Roswell guys for some feedback.

I think we will have to agree to disagree here. What is a better kit than UUC. And dont say Rogue bc I have already done research on it and its not as good IMO. The plastic ball joint in it is the same as stock IMO, only shorter throw. I want a full upgrade, including quality, not only performance.

[ace008]

I got the RP Syncromax installed this past weekend and it is definitely smoother once warmed up. Gearshifts glide into place now. But after I still had the same issue earlier tonight where it was kind of hard getting it into 1st at a stop from neutral. A shift into 2nd then back into 1st worked. This was after not driving the car for 2-3 days.

[secretsquirrel]

I picked up some D4 ATF last week. I will be changing out the fluid in a week or so and doing the CDV delete. The rubbery, notchiness of the clutch is driving me crazy

[lacartus]

I went through an ordeal of notchy shifting on a prior car to the point where I invested a lot of time in oil research that eventually led to a solution. Here's the quick summary, perhaps it will be of help:

Our gearboxes use synchros to aid shifting so we don't have to double-clutch, like all modern manuals. In my prior car the synchros (there is at least one, sometimes more on a gear) were not doing a good job, even though they were in good working order. The synchros need friction to spin and do their job, too much lubrication and there is not enough friction for them to do their job. Too little lubrication (too much friction) and they eat themselves up and need to be replaced.

Basically, a transmission builder told me that there is variation in transmissions, which means there is a different level of lubrication required for the synchros to do their job -- more like a range of lubrication where the synchros work well. Temperature affects this range, so if you are near the edge of the range your transmission may shift better warm or cold. For most transmissions, the recommended fluid provides the necessary friction and it shifts well. As the oil ages the lubrication changes, replacing the fluid at this point may fix the issue. However, as transmissions age, the friction requirement may also change (so I was told).

In my case, the OEM fluid made shifting notchy and after trying several different fluids it still wasn't quite right, but some definitely made it better. Basically, the fluids were close, but not quite right for my transmission. The transmission guru told me that most of the fluids have a friction modifier in them to help hit this perfect balance of lubrication/friction; in fact, many supplier have a range of fluids meant to serve the varying needs of transmissions. Sometimes, the transmission falls between these and none are perfect. My transmission was like this, so he told me the solution was to start with fluid that has no modifier

example: http://www.redlineoil.com/product.aspx?pid=47&pcid=7

Then gradually add modifier one ounce at a time, drive for a while and add more if necessary.

modifier: http://www.redlineoil.com/product.aspx?pid=41&pcid=4

Surprisingly this worked. I found a ratio of modifier to fluid that worked best and tweaked it over time as the transmission got older.

The usual disclaimers apply: Do at your own risk, make sure you pick fluid/modifiers compatible with your transmission; feel free to use this as a starting point in your own research, etc. Hope it helps someone.

BTW: my 6MT shifts fine and I've never felt the need to touch the fluid.

[GaryS]

Originally Posted by rbrown81

Mr 5

I noticed the D4 AFT is recommended by Redline for late model BMW manual transmissions, but do you know why it is recommended over and above the MTL 70W80 GL-4 Gear Oil for manual transmissions?

Anyone know the difference?

Probably most of you have seen the "Alternative BMW Maintenance Schedule" by Mike Miller of Roundel Magazine. I don't personally know anything about gearbox oil, but he says:

All the BMW gearbox re-builders I know use Red Line MTL exclusively, regardless of model year or gearbox. The general consensus is, MTL is the better lubricant. However, the D4ATF product will require less shifter babying during cold operation. I use Red Line MTL in manual gearboxes except where I can’t trust the driver to shift properly when the gearbox is cold, in which case I use Red Line D4 ATF.

[AlanAZ]

I was having the same problem, with Synchromax that had been in 10K miles, over a week's time it became unbearable, and I changed to Redline D4 ATF, was better initially, but then similar. Then had the car in the hills N. of LA, cold compared to PHX, and the next morning, it felt like single weight gear oil was in it.

I called RL tech support, Dave. He suggested it is a clutch problem, that it's not fully releasing, probably due to air or moisture in line (makes sense based on the symptoms.) I'm not sure when, if ever, the clutch has been bleed and flushed. I did that last night, refilled with Motul (be sure to use a pressure bleeder, or you'll be using an oil can from underneath to refill as the system got air locked -- search on bleeding the system), and based on a test drive then, appears to be fixed. I'll know more later today.

I did notice the clutch pedal seemed light recently, now it's firm again, firmer period. And had some drivetrain shudder when slipping the clutch on hill starts.

UPDATE: Yes, that was the fix, gearbox and clutch operating like when I bought the car. I like the D4 ATF, considering it's dead of winter in Phoenix, as it warms up, it provide the right blend of directness and buffering (?).

[Shellacked135i]

My car felt like this since day one. It practically has no miles on it.

[AlanAZ]

I'll probably go with pure D4 ATF next though as I think it'll be better for, on average, colder climates such as Canada

Redline D6 is closest to the factory fluid (MTF-LT-3), and now recommended by RL for our gearboxes, it's about 10% thinner than D4. Warmer climates, you won't notice a difference, but in Canada you will.

Gearboxes are manufactured with tighter and tighter clearances, requiring thinner fluids.

[Mr. 5]

Originally Posted by GaryS

Probably most of you have seen the "Alternative BMW Maintenance Schedule" by Mike Miller of Roundel Magazine. I don't personally know anything about gearbox oil, but he says:

MTL is awesome but for a lot of people, the problem with shifting is in the cold. This is why I recommend the D4 ATF.

[usc335]

I tried Redline MTL and hated it -'it was way too notchy both cold and warm. I then used RP Synchromax and it was great. Then after ~10,000 miles the tranny became really notch. So, I switched back to factory fluid and it was much better. RP seems to break down too fast, but it's great for a while. I think I'm going to try D4 ATF per Mr. 5 next time.

[Former_Boosted_IS]

Has anyone ever seen issues with the synchros from changing the fluid?

[therealm3]

So a quick update for those that care: I’ve had the MTL in my transmission for a few weeks now. Had some low 30’s and as high as 75 superbowl Sunday. It definitely is notchy when cold and was stiffer on the mornings in the 30’s, but it only took a few careful shifts and about two minutes of driving for it to be smooth again. And it is hands down better than the factory fill in my car. I just wish I had taken the 20 min to do it sooner. I’ll happily take the couple hard shifts first off in the morning as a trade off to the 50% of the time notchiness and crunchy shifts I had with the factory fluid.