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Discussion Starter #1
I need to replace my front differential on my 2002 325xi. I found several DIY's on rear swaps but nothing on front. Anyone with any experience have any advice or tips. Thanks
 

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Yeah.

You will need to remove both axles and unbolt the drive shaft. Then you need to drop the front subframe (4 big carriage bolts), and you will be able to unbolt the diff (4 bolts again).

There are DIY's and good write-ups on how to remove the axles. While you are doing that job, drop the knuckles from the front struts- this will give you clearance so you can drop the subframe a few inches to get the diff out.

You must be the person who bought my diff off ebay! Just shipped it to SLC.

PM me with any questions!
 

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Discussion Starter #3
Yup, I did buy the differential from ebay. I appreciated your reply. The swap doesn't sound to difficult. Hopefully I'll feel the same way when i get into it.
 

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You may want to think about new motor mounts while you are doing this job, since you will be undoing them to drop the front subframe. Also, you will need to support the engine with a jack while you drop the subframe. Bolting the subframe back up is a two man job, BTW, especially if you are doing it on your back. The next time I have to drop my front subframe, I'm going to buy 6" longer carriage bolts and replace them one at a time, so that the subframe will hang down just 6 inches, which is plently of clearance to remove the diff or motor mounts, and reinstallaion would be much easier.

I would also buy a new diff output seal (drivers side of the front diff) and a new o-ring on the passenger side of the diff where it connects to the oil pan. Oh, also buy two new bolts that locate the bottom of the struts into the knuckle. I would also buy 2 new axle nuts, and two new axle cir-clips.

Why are you replacing the diff anyway?
 

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Discussion Starter #5
The diff arrived on Monday (the jeans didn't fit) and I am about 3/4 of the way done with the swap.I have the new diff mounted and the subframe reinstalled. The last step is to reinstall the axles, I'll be doing that tonight. I kept the subframe lifted on jacks so I was able to reinstall on my back, by my self. It would have need nice to have a second set of hands to help lift the new diff into place. That was a chore. Thanks for your help.

My old diff is shot. About 8 months ago my front tires locked. I narrowed the problem to the diff and upon exception found that i was low on gear lube. I flushed it and filled her up . It drove OK after the flush although I thought i could feel a little drag and heard a slight noise. I has a few other people listen and drive the car to see if they felt it. Everyone said it felt fine and thought i was just paranoid. A few weeks ago I found out I was not. The front wheels locked again. Spinning the drive shaft flange my old diff confirmed the problem. It was loose and chunky.

I'll make sure to talk you up on ebay. You have been more than helpfull.
 

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OMG I almost forgot to ask you!! You have a manual transmission, right?

This diff won't work in an automatic!!


The diff arrived on Monday (the jeans didn't fit)

Haha. I had some bubble type packing material laying around, but i thought it would probably pop, so i used some old jeans instead, lol.

Was there any indication where the diff fluid leak was coming from? Did you ever have axles replaced? A lot of times you need to top up diff fluid after an axle job.
 

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Discussion Starter #7 (Edited)
And the walls come tumbling down....."This diff won't work in an automatic!!"

I checked the compatibility for different years and models but never checked auto to manual. I have a manual 2002 325xi. and sure enough it a 3.46 ratio. Wow..I was just starting to see the light. Looks like i have a 3.23 for sale. More hours in the garage. The wife is guna be pissed.

You obviously know a hell of a lot more about diffs than i do. I did some quick checking and could not find a 3.46 ratio front diff for my car at a reasonable price. Any advice.

BTW: My axels needed to be replaced twice. Had a local garage do it. Didn't put 2 and 2 together but my diff problem started not to long after the 2nd replacement. I guess i chock it all up to experience.
 

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Do you really have to take both cv axles out to remove the differential? I got driver side out dropped down the sub frame and removed the 4 bolts and the differential will not separate. Why do I have to remove the passenger side cv axle? Im sure the reason I cant get differential out is cause of the passenger axle but it looks like I should just be able to pry apart?
 
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