Slipping out of gear? 2002 SMG

Gentlemen,

I am new to this forum and have a few questions about my '02 smg. I am fairly new to the M3 world and thought to come to you guys first before the dealer. Any help would be greatly appreciated!!

I have a 2002 M3 smg with 87,000 miles on it. I bought it from my brother 20,000 miles ago who had bought it new. I have noticed the past couple of months it feels like it is slipping when I accelerate (easy acceleration) then once it catches there are no issues. It only happened when I would stop and accelerate again. Then yesterday right after I got new rear tires installed I was driving home on the freeway and I noticed I was accelerating and my rpm's were going up and I wasn't going anywhere....it slipped out of gear. It did it a handful of times on my 15 mile ride home. Also, I noticed when I was at about 70mph and I let my foot off the gas it would sometimes drop to 0 rpm's.

What am I looking at here? I want to thank you for your time with this noobie post and any help you could offer.

I've never had to turn a wrench on this car yet but I own a Ford F350 diesel 6.0 that constantly keeps me busy. I'm a decent diy'r but don't know much about the M3's.

Thank You!

James

your should read up on many of the failures that occur with smgs on threads on this forum. normally the hydraulic pump goes bad and causes bad shifts from gear to gear, but the symptom that your describing sounds more like clutch slippage on a manual car. dont forget that the smg is still a manual trans.

Thanks for the reply! I've been reading about the common hydraulic pump issue on the smg's the past few hours on here. Tons of info on this site regarding that. I,too, feel like it's more of a clutch issue but my very limited knowledge of how the smg's work lead me to write this post. How would you go about starting to diagnose a pump issue vs. A clutch issue? No codes have popped up...yet.

well i have a 2002 smg with 72k and although i havent experienced any of the common problems (yet) i do know from what ive read here that when its a pump problem, the car wont shift properly. but that being said people describe it as the revs go high into the gear with response from the accelerator but it just wont shift right, or it shifts really late. alot of people think (me included) that the pump isnt the problem its self in these cases but the temperature sensor for the pump starts over heating and sending inaccurate info the the modules. see but what your describing seems to sound like a worn out clutch thats slipping. my other vehicle is and e46 330ci and when my clutch went on that car, i experienced the exact symptoms your describing now, along with clutch smell coming from the vents.

Search on "compression springs" as well. It's possible those are broken. Is it rev-dependent?

What happens if you give it the beans from a dead stop? Does it slip? Chatter? Give a rpm flare before u feel it engage n take off? Have you been under the car with the belly pan removed inspecting for leaks? I believe air in the system would cause this problem as well

Sent from my SGH-I747M using Bimmer App

Originally Posted by Taunto

What happens if you give it the beans from a dead stop? Does it slip? Chatter? Give a rpm flare before u feel it engage n take off? Have you been under the car with the belly pan removed inspecting for leaks? I believe air in the system would cause this problem as well

Sent from my SGH-I747M using Bimmer App

if he had an air leak in the system due to leak, it would have to be that the pump or the hydraulic fluid (usually pentosin 11s) would be leaking from anywhere in the SMG pump system. shouldnt he just check the hydraulic fluid resevoir that is attatched to the intake manifold towards the rear and see of the fluid level is low, and that way he'll know if hes leaking fluid?

It sounds like clutch slip. If you aren't low in your smg reservoir, I would start by having the smg reset done. New tires would make a difference in clutch engagement and would require smg system to be reset. If you do a search on google with "smg reset" as key words, it will bring up most threads on forums about this subject. Hope this helps.

If the smg reset doesnt help try getting the clutch bite point calibrated by some one who has the software/hardware

The "smg reset" covers all the different procedures. You will need someone with autoenginuity or bmw gt1 or other bmw advanced software.

You could have several issues in play here.

First get the codes read by someone with a BMW scanner.

Then we can make a better determination to what is wrong with your car.

It could be simple or complex.

Did it "slip" out of gear while moving and on power, or coasting or stopped?
Was the gear indicator flashing?
Was the chime going off?
Was the SMG light on?
Has SMG light ever come on during this issue?
Does it not want to up shift while accelerating briskly? If so, what gear/s?

Gentlemen,

Thank you for the responses. I have a few things to add. When I'm driving down the freeway at about 65-70 every now and again it will start to rev higher on the rpm's but my speed does not increase. It feels like I shifted to neutral with the same pressure on the gas pedal. The dash display stays in whatever gear I was in which at that speed would be 6th gear. Now when I don't have my foot into the pedal much because I'm starting to slow down or driving down a slight hill or even if I take my foot off the accelerator completely it will drop to idle on the tach (900 rpm). If I take off hard from a light or accelerate hard on the freeway the car feels fine!
Also, the problem started right after I left the tire shop for new rear tires. That leads me to my next issue. The m3 originally came with the stock 18's and about 3-4 years ago I put stock 19's on it with no issues (besides a way different ride). I decided to go with a 45 series tire in the rear rather than the stock 40. I'm not impressed with the look and will go back to the 40 series as soon as these wear out. Does switching to a 275/45/19 over the stock 275/40/19 give me the issues I'm having?
At 40,831 miles BMW (Cunningham BMW at the time) fixed a handful of issues under warranty. They fixed a broken clutch master cylinder, broken clutch release, put in a rmfd clutch, rel lever, retnr spring, ball pin, bolt, prntosin VHF 11s, and clamp (I copied the part description exactly how my work order from BMW reads).
So 47,000 EASY daily driver grandpa miles I'm having the 'slipping' issue!

Any help would be greatly appreciated!