Edit 1-23-12: fixed it Intermittent slippage in Tranny

[Ghost-Flame]

It's not a big problem but every 2 weeks or so on really cold mornings below 20F. My trans slips when I first put it in drive. I stop the car, move the shift selector to park, shut the car off. Then restart in 20 seconds and everything is fine. This has happened 3 times in the last month or 5 weeks.

I just did a drain and refill (50,000 miles) 2 times with Mobil1, dexv1. which is what mt BMW dealer told me to use and have for changes at 90K and 140K.

Any thoughts. 2002, 3.0, gm transmission. 144,000 miles. Am I experiencing a sign/idiosyncracy of age or is my transmission going to fail soon?

[dkl]

Check your filter. Do you have an OEM or Aftermarket filter? I had the exact symptom as you not too long after installing an aftermarket filter. Replaced it with a Genuine BMW OEM (Filtran) fiilter and my problem went away. No slipping for the past 10K+ miles. Problem with the 3.0i transmission filter is that it is only held in place with the o-ring gasket. If that o-ring doesn't seal properly, most of the time, the filter will end up sitting on the pan (mostly during cold mornings after sitting overnight - transmission will slip) until pressure builds up to suck it back up into place (a minute or so after putting into drive - no slip).

[Ghost-Flame]

Originally Posted by dkl

Check your filter. Do you have an OEM or Aftermarket filter? I had the exact symptom as you not too long after installing an aftermarket filter. Replaced it with a Genuine BMW OEM (Filtran) fiilter and my problem went away. No slipping for the past 10K+ miles. Problem with the 3.0i transmission filter is that it is only held in place with the o-ring gasket. If that o-ring doesn't seal properly, most of the time, the filter will end up sitting on the pan (mostly during cold mornings after sitting overnight - transmission will slip) until pressure builds up to suck it back up into place (a minute or so after putting into drive - no slip).

I did use an aftermarket filter. This morning it was 15 degrees F. It wanted to go faster but it just couldn't. Had to stop, take it out of gerr and start over. I pulled out and held the rpms below 2000 for a couple minute. Then it ran like it is brand new.

I guess I'll be taking the pan off again soon. I was hoping to go a year or 2 before removing those 22 million torques bits. I'm goin to invest in a speed bit for my cordless drill. My arms are still tired from loosening all those bolts.

[Ghost-Flame]

Alright, I changed the filter to a genuine BMW and changed the fluid again, did it a full 4 times drain (used 15 qts) and refill with Dex6 to get the Mobil1 one out of there.

Everything is perfect. Shifts better no slipage ever. I realized I had gotten used to milder slippage from a dead stop, trouncing the gas pedal while passing, and going up hills. The new filter and the right fluid seems to have fixed it. I'm guessing the aftermarket filter couldn't keep up with the demand of the transmission under a load.

Here's a question. The new filter did not come with new bolts for the pan. I use the old ones out of 20 bolts I was able to torque 14 or 15 of them to 15 ft lbs. The other 5, I could only torque them to around 5 ft lbs. They felt like they were stretching.

I've driven about 300 miles and no leaks. should I just leave it until next time or should I go buy the bolts and replace them?

[dkl]

Glad to hear that it was a relatively "simple" fix!

Since I'm rather anal about getting things done right, I would get new bolts.

[JCL]

Filters don't usually cause slipping, but the bad filter could have caused the slow engagement you were experiencing.

Correct fluid has the right friction modifiers, so the wrong fluid is the most likely cause of the slipping.

[dkl]

That was the exact answer my indy told me. He was 99% sure that it wasn't the filter that was causing my issue. But I insisted that we gave replacing the filter a try anyway just to rule that out since it was relatively inexpensive compared to other options. There's a fine line between slow engagement and slipping depending on how you describe the symptom. A slow engagement (half or not engaged) would feel exactly like slipping (engine rev'ving and car is not/slow moving).

[SlickGT1]

Glad to hear ghost. Did you follow the instructions I suggested. Curious to see if you noticed getting more fluid in there this time around. I sure as hell did. My issues are also gone.

By the way, my fluid came out black again on second pan drop and fill. How about you?

[Ghost-Flame]

Originally Posted by SlickGT1

Glad to hear ghost. Did you follow the instructions I suggested. Curious to see if you noticed getting more fluid in there this time around. I sure as hell did. My issues are also gone.

By the way, my fluid came out black again on second pan drop and fill. How about you?

First off I did get the new pan bolts this morning. I will put them on tomorrow. The dealer and online they wanted $2.95 per bolt there are 20. No one else caries the flange bolts. I went to fastenal and I got 20 nickel bolts and washers. It should work fine, This is a non critical bolt, except for the proper torque spec. The bolts I got are nickel hex bolts, 6m 1.0 16mm 8.8 tensil strength. that's 3 times the strength of the stock bolts but they need washers. for $5 for everything. I just have to be careful to not overtorque. The stock bolts are torqued 15 ft lbs. I'll torque to 10 ft lbs and watch for leaks. If it needs more I can always add more torque.

Yes I did follow you instruction. I put 3.5 qts in started the car let run for about 10 minutes until the pan was warm to hot to the touch, my internal palm thermometer I was born with, indicated it was 131.0789 degree F. Just about the temp of a hot piece of Pizza. I had the trans in neutral with the car running and put in 58 ozs (1 qt 26ozs). The car was level I had it jacked up and used a level on the flat part of the trans pan to adjust the level.

Next I'm replacing the fuel reg/filter. hopefully tomorrow. I'm having to crank the engine twice to start after it has set for awhile. From the posts here the fuel regulator looses it prime. I guess after 145k miles it's time.

If that doesn't cure it I be going into the steering column to replace the ignition switch.

[SlickGT1]

Yea I'm going to replace the fuel filter with reg as well. No reason really. Just at 78k miles, and previous 2 owners, no one knows what fuel or whatever else is in there.