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      05-28-2010, 10:17 AM   #1
FiascoJ
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Car pops out of second gear when engine braking

When I'm in second gear and engine braking, my Z4 pops into neutral when I engage the clutch. The problem started last week and it is happening frequently but not every time I engine brake. When it pops out of gear there is no grinding just a quiet 'thud' noise. And this happens in second gear only.

Has anyone experienced something like this? I'm really hoping that I don't need to have my transmission rebuilt.

Thanks in advance!
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      05-28-2010, 10:19 AM   #2
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It could be worn out tranny mount bushings.
(easy fix)
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      05-28-2010, 11:53 AM   #3
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Not sure if mounts are the problem but a good possibility. I had a old mid 80's Camaro and it was the syncros. But that's a totally different animal. Probably would not hurt if you have 50,000+ miles on the vehicle to check the mounts out and replace. You can do a visual check to see if they are compressed or worn.

$25.10

http://www.turnermotorsport.com/html...4&subcat_id=82

May be cheaper(probably) from Tischer.

Here is a DIY for a E46. Pretty similar I believe. I did mine in under 1/2 hour. Some tight spots but if you have a wobble extension you should be fine. A set of small hands would have been of some help. Not to hard if your patient and take your time.

http://m3.madrussian.net/diy_re_tranny_mnt.shtml
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Last edited by mousitch; 05-28-2010 at 12:02 PM..
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      05-28-2010, 02:26 PM   #4
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Im glad I did a double take on the DIY. I put the mounts in without aligning the notches to the tranny brace. Doh. Went home at lunch and tore her down. 20 minutes later all is good. It's nice to be the boss.
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      05-28-2010, 06:36 PM   #5
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      05-28-2010, 08:17 PM   #6
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Anyway, why are you engine braking? The proper technique is to use the brakes to slow the car, and to heel-toe at the appropriate time, or to at least rev-match if you are not on the brakes.

Engine braking wears the clutch and is less effective than engine braking. Wheel braking is more effective and brake pads by nature are wear items that are expendable and relatively inexpensive to replace.

Sorry for being a little harsh since I know you personally, but I'm just saying...
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      05-28-2010, 10:00 PM   #7
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WHS +1 ... Brakes = cheap, Engines=expensive.
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      05-29-2010, 01:16 PM   #8
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Quote:
Originally Posted by nlink720 View Post
Anyway, why are you engine braking? The proper technique is to use the brakes to slow the car, and to heel-toe at the appropriate time, or to at least rev-match if you are not on the brakes.

Engine braking wears the clutch and is less effective than engine braking. Wheel braking is more effective and brake pads by nature are wear items that are expendable and relatively inexpensive to replace.

Sorry for being a little harsh since I know you personally, but I'm just saying...
I guess engine braking is misleading since it makes one think of the way a semi truck engine-brakes (down-shifting to slow down). What I mean is keeping the car in gear with no throttle input.... something like driving in second around 30mph, taking foot off throttle and coasting while still in gear. So the car is decelerating with the engine helping slow the car down. The gear pops out as soon as I touch the clutch.

I'm going to buy the tranny mounts and see if that fixes it. I'll change my tranny fluid at the same time since I have to take off the under-body shielding for this.

Thanks for the tips inTgr8r and mousitch! I would have never thought to replace the mount bushings. I'll update this post when I know if the tranny mount fix solves my problem.
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      05-29-2010, 04:15 PM   #9
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I can recommend the Royal Purple Transmission fluid for nice smooth shifting.
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      05-29-2010, 09:32 PM   #10
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Quote:
Originally Posted by Millertime View Post
I'm going to buy the tranny mounts and see if that fixes it. I'll change my tranny fluid at the same time since I have to take off the under-body shielding for this.

Thanks for the tips inTgr8r and mousitch! I would have never thought to replace the mount bushings. I'll update this post when I know if the tranny mount fix solves my problem.
Can you please take some pictures and do a little write up when you change them. I'm sure lots of people would appreciate it!
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      05-29-2010, 11:14 PM   #11
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Quote:
Originally Posted by Blind32 View Post
Can you please take some pictures and do a little write up when you change them. I'm sure lots of people would appreciate it!
^+1

Interested as well.
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      05-30-2010, 08:04 PM   #12
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Why does everybody on this forum act like engine braking is the worst thing you can do to these cars? Sheesh.

Plenty of reasons to engine brake, and if your $50k car can't deal with a little engine braking than we really should have spent our money elsewhere.

More control of the vehicle at all times, and less risk of brake fade. Not a big deal. OP, I'd bet your synchros are shot.
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      06-01-2010, 09:41 AM   #13
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Quote:
Originally Posted by MIKe86 View Post
OP, I'd bet your synchros are shot.
I sure hope not.

The second gear on my car didn't pop out once all weekend.... But who knows if the problem will come back so I will make the fixes you all recommended anyways.

I ordered some Royal Purple Fluid (thanks for the recommendation rcleme05!) and UUC mount bushings and a short shifter. I probably won't have time to install these parts within the next two weeks, but I make a write-up when I do.
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      06-03-2010, 03:07 AM   #14
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I did royal purple for the tanny and diff and I love it.
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      07-21-2010, 11:37 AM   #15
FiascoJ
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Just to update everyone who's interested...

I changed the transmission fluid with Royal Purple and installed the UUC transmission mount bushings and it didn't fix the problem. It helped the problem because the car pops out of gear only if I rev it higher than 5k RPM in second... none the less, it still happens and it's very annoying.

After talking to some mechanics and some S2K drivers, I believe that the problem is a worn detent or detent spring. This problem is common in S2Ks ... but s2ks also have problems with bent counter shafts. The Z3 also has problems with worn shift pins .

The good news is that the synchros are fine so the entire transmission doesn't need to be replaced. Only one of these pin/spring/cover combos needs to be replaced. (Does anyone on this forum know specifically which pin corresponds to second gear?) However, the bad news is that mechanics are quoting me 8-9 hours for this fix. Is that a fair estimate? How long does it take a mechanic to remove a transmission, change a pin, and re-install the transmission? I wish I could do this fix myself but I don't have the ability to drop a transmission and it would be hard to get the right 'drifts' to re-seal the transmission.

On a side note... I love the UUC transmission mount bushings and Royal Purple tranny fluid. The shifting is much more firm and the car chassis has a pleasant vibration in low RPMs. The only gripe I have with this mod is that my glove compartment now rattles due to the extra vibrations... but tightening the screws in the glove compartment will be easy. I'll do a quick write-up on the mount bushings when I find some time, but for now let me say that Madrussian's write-up is very similar to what I had to do... Except that I didn't have to remove as much shielding as he did.
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      07-21-2010, 11:47 AM   #16
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Which UUC Transmission mount bushings did you get? Option 1 2 or 3? Did you get the enforcers?
http://www.uucmotorwerks.com/html_pr...anny/about.htm
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      07-21-2010, 11:55 AM   #17
FiascoJ
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I bought option 1 without the optional enforcers.
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      03-07-2011, 09:42 AM   #18
FiascoJ
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Just wanted to update this post in case someone else runs into the same transmission problem as me...

I switched out all of the detent pins, springs and covers around August of last year. But that didn't fix the problem... This means that the issue is probably in the selector fork which can't be replaced without taking the transmission apart.

This past weekend I installed a used transmission that I found on car-part.com . The car now stays in second gear with the replacement transmission. Additionally, the replacement transmission shifts much more smoothly into first and second gear.

Thanks to everyone that helped me out! And if someone knows of a transmission rebuilding shop that would want to buy a transmission with a bad selector fork, let me know!
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      03-07-2011, 10:07 AM   #19
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Not sure if http://www.levelten.com/ would buy your old tranny, or just does core exchanges, but worth a shot.
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      03-08-2011, 09:37 AM   #20
FiascoJ
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Quote:
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Not sure if http://www.levelten.com/ would buy your old tranny, or just does core exchanges, but worth a shot.
Thanks! I'll give them a try.
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