I'm in too; but grumpy right now, as my X5 6MT just ate its engine. Ever heard of a bend piston ring and broken crown? 10 psi compression on #1... Absolutely no idea how. Wife and son were driving along on I5 to Bay Area, minding their own business when the engine suddenly lost power and started running rough. Trouble codes indicated misfire #1, #3. I got a pair of coils and set of plugs and set off in pursuit. Replaced those, no better. Compression test indicated above result and boroscope revealed tip of piston ring sticking above piston crown. Looks like engine replacement is in the near future. :-(.
Regarding 6MT. I like the car and the character but the gear spacing is not great, especially on 1st and 2nd gears; 1st is too low and 2nd is probably also a little low for good normal driving. Also, shifter on all BMW MT's is sloppier and less precise than I think it should for BMW's pedigree and their excellence in other driving characteristics.

Are you the original owner? So sorry to hear about engine troubles, the M54 is usually a pretty stout motor! Any good BMW engine rebuilders out by you?


The 6MT is a rare find (some would say more rare than pre-facelift with 5-speed), and although the ratios are short especially 1st and 2nd, just be glad you have that 6th for the highway, at 80 mph I'm screaming at about 4k rpm's in 5th!

Wow! That is an odd failure! What is the mileage of your X? I would consider a salvage motor and later do a light rebuild if there is no damage to the cylinder head or walls on your current m54 engine.

As far as the gearing goes, I'm swapping in a pair 2000-2003 4.4i differentials into my 6MT. They are a direct swap and would help reduce the gearing across the board. You 5 speed guys should definitely do this, especially if your not towing big loads. You can sell your old differentials and its a free mod minus the time swapping them out.

Thanks to Sedc, who swapped in some 3.64 ratio differentials from the 4.4i, went an additional step and made his front an LSD diff, reported that he got an additional couple of MPG's and gearing that is easier to live with.

Here's a link to the thread if your interested. Its on the top of my list of mods to come.

http://www.xoutpost.com/bmw-sav-foru...ted-slips.html

x2 dragon this is DEFINITELY on my list of to-do's, 3.64s front and rear would be great, I don't tow and could definitely use some improved mileage, don't need the LSD although it would be nice.

My problem is finding affordable, low mileage diffs, my stock diffs have 68k on them and have already had the gear oil changed at least once, I'm leary about buying diffs that are 120k+ miles and never had the fluids changed, wouldn't want to replace with a higher worn part you know?

And as far as the swap goes do you think swapping diffs is DIYable or is it def somthing a shop should handle?

Ricky Bobby, (Shake n' Bake!)

It's totally DIyable. As a matter of fact, far more easy than the Bentley manual suggests. Bentley has this huge complicated process for the front diff....... but for us 3.0 guys, the diffs slip in and out. I bet about an afternoon job with swapping them both out and new fluid, which I too have done not long ago, and that's my snail meticulous pace.

I'm super jealous of your 68k mileage. I'm close to double that. ;) I'm gonna go on the cheap. I've found a set for about 300-400 bucks for the pair, just gotta know who to talk to. I plan on keeping my 4.10's for the time being in the corner, but it may make sense to sell'em. I plan on doing a write up on it next month. I'll post my source from where I find em. Good Luck bud.

I personally like the gearing. For me as a 5 speed owner I would REALLY like to have the 6th gear for the freeway, but otherwise find the gearing to be ok. Is there any chance the gearing and diff's are different from truck to truck? The supercharger combined with the gearing especially 1st, 2nd, and 3rd is pretty amazing. 4th I don't know, maybe it's me or I just haven't found the sweet spot but its kinda blah. 5th is cool because I can easily pass on the freeway with great pickup by flooring it. I always set my cruise at 70 mph, but once I find my place on the freeway I need 6th gear bottom line. The brand new X5's are somewhere in the 2000 rpm range at 70 mph in I believe 7th gear judging by a quick glance at their cluster, correct me if I am wrong please, curious to know. My mileage is too low to replace the tranny right now, but maybe when it's clutch time I can locate a 6 speed tranny and upgrade. 6 gears along with the supercharger should get me a few mpg's, the supercharger alone helped quite a bit in conjunction with the cruise.

With the additional torque of your supercharger, you must be sling shotting through the gears. 1st gear is already a blip for me. I'm worried about the syncros on my tranny between 1st and 2nd. I have been babying mine with soft 2nd starts when I can. Revvving the hell out of it in first just to cross an intersection just to get to 10 mph. 3.0 all have 4.10 diffs. 4.4i have 3.64 diffs till late 03 and then switched to 4.10 with the lci and transmission update. 4.6is have 3.91 and the 3.0d have a 3.73 or a 3.46... If I remember right.4.8is have 4.10 I think.

Any thoughts about 2 different TC-types? How do you suppose to upgrade the tranny to 6-speed?

Nick, I was under the impression you could swap the tranny and the case. Is it not possible? Dragon, I read another post like yours about the 10 mph in 1st thing, and I just don't understand? Mine doesn't perform like that. That's why I asked if there was a possibility some were different. I like 1st! But, I see some owners here disagree. My 1st will lay your ass back in the seat! LoL, pardon my language. It's just that last gear (6) I need for freeway cruising, and I'm getting the impression from Nick it's not possible. The one good thing I have going for me is my tranny still performs like new, it's been babied since day 1.

Happy, maybe you could take a video of driving around? 1st gear for all 3.0's should be a really short stump puller gear, what Dragon talks about is when you are trying to pull out into traffic quick, if you drop the clutch and go, 1st is so short that by the time you are doing 10 mph you are almost at redline lol! And I know what he means, 1st is ridiculously short but I think the 3.0 is geared tall to have better response on highway and acceleration (when doing 80 mph in 5th on the highway we are at 4k, so no need to downshift to pass)