M-coupe Diff Cover?

[L84THSKY]

Where is the best deal on an M-coupe finned rear diff cover? Also, does the speedo sensor work for any diff to diff rear cover swap? I would prefer to just pop the sensor out of the cover that came with the diff, and put it in the M-coupe cover.

[cali-ti]

got mine on ebay from bimmerbum (he may still be out of the country though). think it was $175 + shipping so plan on about $200.

i BELIEVE the speedos are the same size. i bought a new one for the e30 diff i used (3.73) and it fit fine. the wire for the ti was a little tighter since you have to go further to reach the new sensor location.

[L84THSKY]

I just ordered mine from the same guy. I sure hope this diff swap goes smoothly. Someone on Bimmerforums said it took him 12 hrs with a buddy. But maybe they had more work than me. I'm just swapping diffs, that's all.

got mine on ebay from bimmerbum (he may still be out of the country though). think it was $175 + shipping so plan on about $200.

i BELIEVE the speedos are the same size. i bought a new one for the e30 diff i used (3.73) and it fit fine. the wire for the ti was a little tighter since you have to go further to reach the new sensor location.

[cali-ti]

you can't plan for the unknown. good luck! :biggrin:

[L84THSKY]

Did you replace any of the bolts that mount up the diff to the car or the flange bolts/nuts?

you can't plan for the unknown. good luck! :biggrin:

[cali-ti]

i refreshed the nuts that attach the drive shaft to the front of the diff, the bolts for mounting the diff in the carrier, as well as the bolts that attach the half shafts to the diff flanges (there are two types for the e30 flanges, but i'm not sure about the 318ti ones). you'll be getting all the bolts for the diff cover, but i also got the new speedo sensor and all hardware for attaching it. since i was swapping half shafts, i also refreshed the nuts/lock rings on the ends of the shafts. i basically refreshed (even got extras of a good number of them) all the mounting/attaching hardware i could. keep in mind the drive shaft nuts at the front of the diff are ONE TIME USE. fit it up there with your original nuts and then use the new ones to do the final attaching.

[L84THSKY]

Eric

I'm going through the parts list off realoem, and I'm not sure about the locking nuts for the drive shaft. Is it part #15 or #16? Part 16 uses some type of weighs along with the nuts/bolts.

http://www.realoem.com/bmw/showparts.do?model=CG73&mospid=47506&btnr=26_0105&hg=26&fg=10

Also, the halfshaft flange bolts use some sort of spacers, and two types of spacers are listed, part #2.

http://www.realoem.com/bmw/showparts.do?model=CG73&mospid=47506&btnr=33_1106&hg=33&fg=25
i refreshed the nuts that attach the drive shaft to the front of the diff, the bolts for mounting the diff in the carrier, as well as the bolts that attach the half shafts to the diff flanges (there are two types for the e30 flanges, but i'm not sure about the 318ti ones). you'll be getting all the bolts for the diff cover, but i also got the new speedo sensor and all hardware for attaching it. since i was swapping half shafts, i also refreshed the nuts/lock rings on the ends of the shafts. i basically refreshed (even got extras of a good number of them) all the mounting/attaching hardware i could. keep in mind the drive shaft nuts at the front of the diff are ONE TIME USE. fit it up there with your original nuts and then use the new ones to do the final attaching.

[AlaskaBlue]

Cali-ti, how much faster does the car feel with a different diff? It is an upgrade I have been considering. 3.45-3.73

[cali-ti]

i got the nuts w/o weights (#15). i don't know what the differences between the reinforcements are (#2). you could either get both (3 per size i believe) or not bother as your originals will most likely be fine.

[cali-ti]

it definitely feels a good bit faster. it's been called the "poor man's supercharger" ... i'm not sure i'd go that far, but it is noticeable with the butt-dyno :)

the big gain is the limited slip as you have much better traction. i need to find the relay for the traction control so i can disable it - it REALLY gets in the way when you have a LSD. i would re-enable it for snow, but otherwise i would prefer to have it off (and it resets everytime you turn the car off when using the switch inside - not to mention the large obnoxious hazard symbol in the cluster).

it WILL be more annoying at highway speeds, at least if you drive 80+mph. you'll be revving about 10% higher at any given speed. 80mph is now around 4000rpm or a little higher. if you're going to supercharge or drop in a 6, i wouldn't do the 3.73.

[DustenT]

Get a friend to help with the diff swap. It takes alot of time and strenght to get everything lined up right.

[L84THSKY]

Funny you should say that. Unlike alot of you guys, I lived overseas for a decade, and then returned to Long Island. All of my high school friends are gone, and all I have is my night school (Married) friends. I can use my brother's lift, but he is probably too busy to help with the install. That leaves my girlfriend, and I doubt she will be much help.

I'm gonna get all the needed nuts and bolts, swap the rear cover and add the fluid. Then I will shop around to have the diff swapped. Since the halfshafts aren't being swapped, it shouldn't cost too much to have the diff swapped.

I'll keep you posted, have to make a few calls.

Get a friend to help with the diff swap. It takes alot of time and strenght to get everything lined up right.

[L84THSKY]

Just got a quote from a BMW specialist on Long Island. $450.00-$500.00 just to swap diffs. He said it is about a 5 hr job.

http://www.littlegarage.com/?drg=143-4204212367

[AlaskaBlue]

wow your labor is expensive.. The BMW mechanics around here charge $50-75 an hour. Dealer charges $86.

[cali-ti]

that's about the rate i paid (around $80) in lake bluff, IL. my guys indicated they charged more per labor hour if you brought in your own parts (as they lose that parts income).