[smokinu454]

Hey guys, so I have a 2015 535i with the sport 8AT. The car has 112k miles and has the following modifications. BMS intercooler, VRSF catless DP, VRSF chargepipe, MHD stage 2+ 93oct tune, and XHP stage 3 trans tune. All mods were done at about the same time and I have about 25K miles on this setup. Car seems to run good. I do oil changes every 3K miles and spark plugs every 20k. My question is how well I can expect this trans to hold on at this power level? I gave it a hard run yesterday (10-80 WOT) and when i pulled in the driveway a mile later I smelled something that smelled like what I could only describe as burnt clutch material or maybe burnt brake pad material. I wasnt on the brakes very hard so it made me wonder. Anyways, just wanted to get your guys' thoughts. Thanks!

[ctcarbonari]

Originally Posted by smokinu454

I do oil changes every 3K miles and spark plugs every 20k. My question is how well I can expect this trans to hold on at this power level?

How often are you servicing your transmission by doing oil/filter changes, replacing mechtronic sleeve & solenoid seals?

[smokinu454]

@ctcarbonari In the last 30k miles I have not. Havent even heard of the last thing to be honest.

[ctcarbonari]

Personally, I'm a believer in changing all fluids & filters often. They're the lifeblood of your car. Much like you, I'm curious to hear other peoples experiences with their ZF transmission & tunes.

FWIW, ZF (the manufacturer of your transmission) recommends oil/filter servicing at ~60k mile intervals. NO FLUSH - it's a gravity drain & fill process that swaps out about 1/2 to 2/3 of the old oil. So, many people will do a drain & fill, run for a few hundred miles, then do another drain & fill while changing out the integral filter/pan the second time around. The unique part of this servicing is the secondary fill process where you'll need to have the car lifted-level-and running while you cycle thru the gears w/ the transmission "at temperature" to top off the oil. (See attached pdf).

When I had my ZF 8HP transmission serviced @ 60k miles my mechanic recommended replacing the mechtronic sleeve as PM. When I do this again @ ~120k miles I'll do the same and go ahead and replace the solenoid seals as well.

also, FWIW, see attached the oil analysis done on my transmisson oil for a stock 15' 535i w/ 8-speed steptronic transmission. I'm thankful I had it done and as preventative maintenance I do drain & fill servicing of the fluid annually inbetween the filter/pan change cycles.

[Thecastle]

I'll be frank, most of the mechatronic sleeve stuff and solenoids were more of a problem on the 6 speed transmission. The 8 speeds are about as good as any automatic, its in the Dodge Demon, Ram 1500 pickups and tons of european cars.

https://blog.fcpeuro.com/zf-8-speed-...cs-maintenance

The harder you drive the car the sooner the transmission will wear out and break. ITs as simple as that, and if you transmission lives beyond 150,000 miles consider that excellent. Most auto's don't last even 200K miles, they wear out (clutches go).

I'd suspect your burning smell wasn't the transmission. It was probably your breaks. You would know if your trans was slipping its clutches you'd see it in the rpm's,

[SWFLf10]

FWIW my F10 has over 170,000 miles and has had the Bm3 stage 2 tune and xHP tune for about 40,000 miles with no issue.

I also believe in regular fluid and liter changes. The first trans fluid and filter change was done by me when I bought the car at about 70,000 miles. I haven’t touched it since, but plan on doing it soon. I really believe it should be done every 40-60k miles as preventative maintenance.

[Double Nickel]

Me too movement, Get some fresh fluid put in there by a small local business that do tranny and gear work wit a nice clean enviroment and good tools and machines. You be looking at bout 200 for a fcp moly kit and bout 300 for their time and labor and your peace of mind.

[cip_and_dale]

did you ask the BMW representative?

[95blkmax]

ZF 8HP can take a beating. I did my 1st service on the trans at 113k (I think) miles, I'm at 128k now. Not many miles since but they are 95% street stop n go and a ton of pulls for logging/ tuning.

I used Liqui Moli TopTec1800 and could not be happier. The transmission is also 1- bimmer coded to run the Sport Transmission programming (did that since 109k miles), then 2- sometime around 120k I flashed the mechatronics with xHP stage 3 trans tuning. It's been PHENOMENAL.

You can see my mods in my sig below for reference.