Rear Differential Help

Rmtt · 02-02-2019, 06:04 PM

So I decided to swap my rear diff this afternoon.

I've got a jack with a strap, so I was pretty confident in getting it out on my own. My problem is that I have it completely broken loose, but the driveshaft end won't come uncoupled.

I even got under there and supported the rear diff by hand, and moved it everyway this side of Sunday like I was benching a barbell....and it would not let go on the driveshaft end. If it would have dropped, I could have laid it on my chest as it wasn't as heavy as I thought it would be.

And before the obvious is asked, I have all the bolts that were threaded on the driveshaft to the rear diff out.

Could it be just frozen up that bad? I just walked away from it a few minutes ago as I don't want to start prying on anything.

Anyone run into this and have suggestions? I would appreciate it as I would love to put it back together in the morning.

Thanks!

Thunderguts · 02-02-2019, 06:32 PM

An overly aggressive snap ring? I'm curious to know since I plan to replace mine eventually also.

Rmtt · 02-02-2019, 06:53 PM

It's pretty much a flat mating surface on the driveshaft side that has about a 1/2" lip that sticks into the flange of the rear diff.

4 threaded E bolts hold it on, same as the axles. Both of those come off easy. I'm sitting here with the entire weight of the rear diff strapped to my jack, but can't seoerate it from the driveshaft flange.

Frustrating!!!! I should be out test this new gear by now

Rmtt · 02-02-2019, 07:59 PM

I guess I will rest on it, then tomorrow put the car out of gear and lightly tap the mating flanges with a deadblow hammer while rotating it. Hopefully that will break it loose.

It's not really a big job at all if you have the proper tools. Some tight clearances here and there...but nothing major.

I just wanted to get the carrier out tonight so I could reinstall everything tomorrow morning.

crowtrobot · 02-02-2019, 08:09 PM

This exact thing happened to me when I did mine back in the spring. It is probably just that frozen. I soaked mine in PB blast overnight, hammered a paint scraper inbetween the flanges to get things started, then worked the flanges apart. It'll eventually separate under its own weight.

Good luck!

chris_flies · 02-02-2019, 08:32 PM

I had the same issue pulling mine out.

As has been said, let it soak in penetrating oil for a while, then tap the ears of the driveshaft inwards with a hammer (some force required) and then pry it straight forward, there's just enough sliding room in the driveshaft.

Good luck! 3.73 gears are awesome for these cars, especially with an LSD...

Rmtt · 02-03-2019, 04:29 AM

Thanks for the replies.

As soon as the sun comes up I plan to get it knocked out.

Rmtt · 02-03-2019, 12:55 PM

So I got it replaced. Took the advice of you guys and took a dead-blow hammer to it. I had already prepped the other 3:73 rear diff with Redline fluid, so I went right back in after getting the stock one out.

Previous posts on this are right.....it really is a 2 person job. Me being stubborn and not wanting to wait, I did it by myself. Longest part after I got it in was coming out and going back under the car multiple times to rotate the driveshaft and rear axles to get access to the bolts. So I probably have close to 5 hours time in it, but I'm OCD about things and double check items. But a second set of hands would have been nice!

Rmtt · 02-03-2019, 01:07 PM

So.....impressions. I haven't really run it hard, just drove around to let things warm up and listen for any unusual noises. Everything seems to be as smooth as before, but you can definitely notice it even driving around town. I don't do a lot of highway driving, so I think it fits me perfect.

But I do have a C6 with a 3:90 gearset, so take things subjectively.

I will take it easy for a few hundred miles even though the donor car that I got the diff out of barely had 20K miles. The fluid I drained out looked very good, so that makes me feel better even though I didn't open the housing.

But even going easy, the response is much more livelier. It makes you want to "wind it out".

I think I will probably give it 500 miles or so, then replace the fluid again as I have enough for another fill and see how it looks.

Also....if I were to do it again.....I would in retrospect have a friend around. It would speed the process up tremendously.

So I think my next project will be my 3 Stage Intake along with a BPC tune. Then I will more than likely move on to MILVS and a tune upgrade. After all that proves out, I will see how the header situation around here looks with the idling issues.

I have AA longtubes in storage, but a little hesitant about them at the moment.

Plus I hope my new Apex Arc-8 wheels show up this month. That should set the tone for some appearance mods, plus the weight savings are pretty sweet!

desertman123 · 02-03-2019, 08:31 PM

congrats!!

yeah even with my Florida car I had to wack the driveshaft (lol) so I can't imagine any place with rust.

You're gonna love every mod you add, you're going straight for the throat with mods too. Every mod makes you wanna floor it everywhere too.

Header install is annoying though.. just really inconvenient. If I had an excuse to pull the motor, I would redo the job properly. MILVS were also awful, I couldn't figure out the standard method so I used the BimmerLabs one (pulling the spring leg off the intermediate rocker) and it was a big pain

Lemme know if you need advice on any of those jobs (and this goes for anyone reading lol), there's info everywhere but there's always those mid-job things. If you have Instagram id get back to you pretty quickly @andreys_128i

Rmtt · 02-04-2019, 07:56 AM

Quote:

Originally Posted by desertman123

congrats!!

yeah even with my Florida car I had to wack the driveshaft (lol) so I can't imagine any place with rust.

You're gonna love every mod you add, you're going straight for the throat with mods too. Every mod makes you wanna floor it everywhere too.

Header install is annoying though.. just really inconvenient. If I had an excuse to pull the motor, I would redo the job properly. MILVS were also awful, I couldn't figure out the standard method so I used the BimmerLabs one (pulling the spring leg off the intermediate rocker) and it was a big pain

Lemme know if you need advice on any of those jobs (and this goes for anyone reading lol), there's info everywhere but there's always those mid-job things. If you have Instagram id get back to you pretty quickly @andreys_128i

Thanks for the offer! It always helps to have a second set of eyes that has been there and done it before to ask when things throw you a curve ball.

chris_flies · 02-04-2019, 05:21 PM

Quote:

Originally Posted by Rmtt

Quote:

Originally Posted by desertman123

congrats!!

yeah even with my Florida car I had to wack the driveshaft (lol) so I can't imagine any place with rust.

You're gonna love every mod you add, you're going straight for the throat with mods too. Every mod makes you wanna floor it everywhere too.

Header install is annoying though.. just really inconvenient. If I had an excuse to pull the motor, I would redo the job properly. MILVS were also awful, I couldn't figure out the standard method so I used the BimmerLabs one (pulling the spring leg off the intermediate rocker) and it was a big pain

Lemme know if you need advice on any of those jobs (and this goes for anyone reading lol), there's info everywhere but there's always those mid-job things. If you have Instagram id get back to you pretty quickly @andreys_128i

Thanks for the offer! It always helps to have a second set of eyes that has been there and done it before to ask when things throw you a curve ball.

A hammer and blowtorch also helps

*Breaks something*

:

Rmtt · 02-04-2019, 06:58 PM

Quote:

Originally Posted by chris_flies

A hammer and blowtorch also helps

*Breaks something*

:

Lol....if it breaks....then it was meant to be broken! Plus that's what they make duct tape for.

chris_flies · 02-04-2019, 07:00 PM

Quote:

Originally Posted by Rmtt

Quote:

Originally Posted by chris_flies

A hammer and blowtorch also helps

*Breaks something*

:

Lol....if it breaks....then it was meant to be broken! Plus that's what they make duct tape for.

That's the spirit!

Rmtt · 02-05-2019, 03:09 PM

Quote:

Originally Posted by chris_flies

That's the spirit!

Yep....I even have a T-shirt that says so!!

MightyMouseTech · 02-05-2019, 08:33 PM

Quote:

Originally Posted by Rmtt

Quote:

Originally Posted by chris_flies

A hammer and blowtorch also helps

*Breaks something*

:

Lol....if it breaks....then it was meant to be broken! Plus that's what they make duct tape for.

As a tech.

Can't be seized if it's a liquid.

LOL

Rmtt · 02-06-2019, 02:13 PM

Quote:

Originally Posted by MightyMouseTech

As a tech.

Can't be seized if it's a liquid.

LOL

Lol.....I'm in an Engineer in a chemical plant. Don't know if I can agree with that statement as we have some pretty inept people working there.

It seems common sense isn't being given out like it used to be!

cwlo · 02-09-2020, 10:40 AM

Old thread I know, but here's the proper way to free the driveshaft from diff. The Diff flange has some extra holes in it that are not threaded. You can take a punch and from the back side, put the punch through the open hole of diff flange, and onto the driveshaft flange. This gives you the ability to hit the driveshaft flange directly in the correct direction (forward) to break free from the diff. Easy and safe solution.

02-02-2019, 06:04 PM	#1
Rmtt Colonel 8211 Rep 2,250 Posts Drives: 2011 BMW 128i, 2008 LS3 C6 Join Date: Jan 2019 Location: South Carolina iTrader: (3)	Rear Differential Help So I decided to swap my rear diff this afternoon. I've got a jack with a strap, so I was pretty confident in getting it out on my own. My problem is that I have it completely broken loose, but the driveshaft end won't come uncoupled. I even got under there and supported the rear diff by hand, and moved it everyway this side of Sunday like I was benching a barbell....and it would not let go on the driveshaft end. If it would have dropped, I could have laid it on my chest as it wasn't as heavy as I thought it would be. And before the obvious is asked, I have all the bolts that were threaded on the driveshaft to the rear diff out. Could it be just frozen up that bad? I just walked away from it a few minutes ago as I don't want to start prying on anything. Anyone run into this and have suggestions? I would appreciate it as I would love to put it back together in the morning. Thanks! __________________ Everybody has a gameplan....until they get punched in the mouth.
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02-02-2019, 06:32 PM	#2
Thunderguts Captain 778 Rep 996 Posts Drives: 2009 128i Sport MT Join Date: Jul 2018 Location: DFW iTrader: (0)	An overly aggressive snap ring? I'm curious to know since I plan to replace mine eventually also.
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02-02-2019, 06:53 PM	#3
Rmtt Colonel 8211 Rep 2,250 Posts Drives: 2011 BMW 128i, 2008 LS3 C6 Join Date: Jan 2019 Location: South Carolina iTrader: (3)	It's pretty much a flat mating surface on the driveshaft side that has about a 1/2" lip that sticks into the flange of the rear diff. 4 threaded E bolts hold it on, same as the axles. Both of those come off easy. I'm sitting here with the entire weight of the rear diff strapped to my jack, but can't seoerate it from the driveshaft flange. Frustrating!!!! I should be out test this new gear by now
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02-02-2019, 07:59 PM	#4
Rmtt Colonel 8211 Rep 2,250 Posts Drives: 2011 BMW 128i, 2008 LS3 C6 Join Date: Jan 2019 Location: South Carolina iTrader: (3)	I guess I will rest on it, then tomorrow put the car out of gear and lightly tap the mating flanges with a deadblow hammer while rotating it. Hopefully that will break it loose. It's not really a big job at all if you have the proper tools. Some tight clearances here and there...but nothing major. I just wanted to get the carrier out tonight so I could reinstall everything tomorrow morning.
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02-02-2019, 08:09 PM	#5
crowtrobot First Lieutenant 366 Rep 317 Posts Drives: 2008 M3 Join Date: Sep 2015 Location: Philly iTrader: (1)	This exact thing happened to me when I did mine back in the spring. It is probably just that frozen. I soaked mine in PB blast overnight, hammered a paint scraper inbetween the flanges to get things started, then worked the flanges apart. It'll eventually separate under its own weight. Good luck!
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02-02-2019, 08:32 PM	#6
chris_flies Sideways and Smiling 3027 Rep 2,860 Posts Drives: In Exuberance Join Date: Mar 2017 Location: Rosamond, CA USA iTrader: (0) Garage List 2012 BMW E91 328i [0.00]	I had the same issue pulling mine out. As has been said, let it soak in penetrating oil for a while, then tap the ears of the driveshaft inwards with a hammer (some force required) and then pry it straight forward, there's just enough sliding room in the driveshaft. Good luck! 3.73 gears are awesome for these cars, especially with an LSD... __________________ 2012 BMW 328i 6-Speed Wagon \| Deep Sea Blue with Grey Dakota Leather \| Manual Swap, 330i Intake + Tune, 3.15 Helical LSD, Öhlins R&T (SOLD) 2009 BMW 128i 6-Speed Coupé \| Monaco Blue with Black Sensatec \| chris_flies' 128i thread
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02-03-2019, 04:29 AM	#7
Rmtt Colonel 8211 Rep 2,250 Posts Drives: 2011 BMW 128i, 2008 LS3 C6 Join Date: Jan 2019 Location: South Carolina iTrader: (3)	Thanks for the replies. As soon as the sun comes up I plan to get it knocked out.
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02-03-2019, 12:55 PM	#8
Rmtt Colonel 8211 Rep 2,250 Posts Drives: 2011 BMW 128i, 2008 LS3 C6 Join Date: Jan 2019 Location: South Carolina iTrader: (3)	So I got it replaced. Took the advice of you guys and took a dead-blow hammer to it. I had already prepped the other 3:73 rear diff with Redline fluid, so I went right back in after getting the stock one out. Previous posts on this are right.....it really is a 2 person job. Me being stubborn and not wanting to wait, I did it by myself. Longest part after I got it in was coming out and going back under the car multiple times to rotate the driveshaft and rear axles to get access to the bolts. So I probably have close to 5 hours time in it, but I'm OCD about things and double check items. But a second set of hands would have been nice!
	Appreciate 0 Quote

02-03-2019, 01:07 PM	#9
Rmtt Colonel 8211 Rep 2,250 Posts Drives: 2011 BMW 128i, 2008 LS3 C6 Join Date: Jan 2019 Location: South Carolina iTrader: (3)	So.....impressions. I haven't really run it hard, just drove around to let things warm up and listen for any unusual noises. Everything seems to be as smooth as before, but you can definitely notice it even driving around town. I don't do a lot of highway driving, so I think it fits me perfect. But I do have a C6 with a 3:90 gearset, so take things subjectively. I will take it easy for a few hundred miles even though the donor car that I got the diff out of barely had 20K miles. The fluid I drained out looked very good, so that makes me feel better even though I didn't open the housing. But even going easy, the response is much more livelier. It makes you want to "wind it out". I think I will probably give it 500 miles or so, then replace the fluid again as I have enough for another fill and see how it looks. Also....if I were to do it again.....I would in retrospect have a friend around. It would speed the process up tremendously. So I think my next project will be my 3 Stage Intake along with a BPC tune. Then I will more than likely move on to MILVS and a tune upgrade. After all that proves out, I will see how the header situation around here looks with the idling issues. I have AA longtubes in storage, but a little hesitant about them at the moment. Plus I hope my new Apex Arc-8 wheels show up this month. That should set the tone for some appearance mods, plus the weight savings are pretty sweet!
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02-03-2019, 08:31 PM	#10
desertman123 E82 Mudflap Ambassador 2214 Rep 2,219 Posts Drives: '08 128i Join Date: May 2016 Location: Orlando, FL iTrader: (0) Garage List 1992 Honda Beat [9.50] 2008 BMW 128i [10.00] 2014 BMW 528i [10.00]	congrats!! yeah even with my Florida car I had to wack the driveshaft (lol) so I can't imagine any place with rust. You're gonna love every mod you add, you're going straight for the throat with mods too. Every mod makes you wanna floor it everywhere too. Header install is annoying though.. just really inconvenient. If I had an excuse to pull the motor, I would redo the job properly. MILVS were also awful, I couldn't figure out the standard method so I used the BimmerLabs one (pulling the spring leg off the intermediate rocker) and it was a big pain Lemme know if you need advice on any of those jobs (and this goes for anyone reading lol), there's info everywhere but there's always those mid-job things. If you have Instagram id get back to you pretty quickly @andreys_128i __________________ My 2008 128i - Sparkling Graphite/Beige - Sport pkg - 6MT - Click me! Parents' 2014 528i - Mineral White/Ivory White - fully loaded Instagram @Andreys_128i and @Honda.Bito
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02-09-2020, 10:40 AM	#18
cwlo Private First Class 84 Rep 110 Posts Drives: 04 m3 Join Date: Dec 2017 Location: Chicago iTrader: (0)	Old thread I know, but here's the proper way to free the driveshaft from diff. The Diff flange has some extra holes in it that are not threaded. You can take a punch and from the back side, put the punch through the open hole of diff flange, and onto the driveshaft flange. This gives you the ability to hit the driveshaft flange directly in the correct direction (forward) to break free from the diff. Easy and safe solution.
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