DIY needed for diff front bushing

[M3GA]

Failed PA inspection today for front diff bushing. Does anyone have a DIY on this? I do have the TIS guides, though prefer DIY.

Also, I need to get the car up and running quickly, to be reinspected. So what would be the shortest way to just replace the front diff bushing? Can it be done without removing the diff (ex leaning/lowering it)? I'll be installing OE BMW bushing (not poly).

I ordered ECS Tuning Schwaben subframe/diff bushing tool, which doesnt require removing subframe.

At a later point I'll replace the subframe bushings and rear diff bushings. Just need to pass inspection for now.

[oceansize]

It can't be removed without dropping the diff. I used the new bushing to press the old one out via an RTAB tool. See this thread at e46fanatics.

By using the new bushing to push the old one out I didn't have to hack up anything.

Edit: I also didn’t have to use heat or put the new one in a freezer although the cold can’t hurt.

[Flat-Six]

Make sure you lubricate the tool threads going back in. I also used a floor jack with a 2x4 at an angle to position the Diff when threading in the bolt, made it very easy, as I rotated the diff with the 2x4 very gently when threading the bolt back in to avoid cross-threading.

[M3GA]

It can be removed without dropping the diff. I used the new bushing to press the old one out via an RTAB tool. See this thread at e46fanatics.

By using the new bushing to push the old one out I didn't have to hack up anything.

Edit: I also didn’t have to use heat or put the new one in a freezer although the cold can’t hurt.

The thread you referenced shows the diff completely removed. How were you able to set up your tool with diff in place?

Also, still assume you have to remove exhaust (or lower), heat shield, disconnect drive shaft and two output shafts, and rear sway bar. Please confirm.

[M3GA]

Make sure you lubricate the tool threads going back in. I also used a floor jack with a 2x4 at an angle to position the Diff when threading in the bolt, made it very easy, as I rotated the diff with the 2x4 very gently when threading the bolt back in to avoid cross-threading.

Yes, lots of grease or oil will be used! Good idea to use 2x4 to pivot the diff to line up bolts.

[t3ddftw]

That bolt is extremely easy to cross thread. Ask me how I know...

[heinzboehmer]

Also, still assume you have to remove exhaust (or lower), heat shield, disconnect drive shaft and two output shafts, and rear sway bar. Please confirm.

No need to remove exhaust or heat shield. The heat shield has an access hole that'll let you get to all the drive shaft bolts.

I honestly have no clue how oceansize changed this bushing without removing the diff. Luckily it's not too much more work to completely remove it than it is to try and do this with the diff still on the car.

That bolt is extremely easy to cross thread. Ask me how I know...

Yup! I completely destroyed the threads in my diff the first time I put that bolt back in.

[M3GA]

No need to remove exhaust or heat shield. The heat shield has an access hole that'll let you get to all the drive shaft bolts.

I honestly have no clue how oceansize changed this bushing without removing the diff. Luckily it's not too much more work to completely remove it than it is to try and do this with the diff still on the car.



Yup! I completely destroyed the threads in my diff the first time I put that bolt back in.

perfect! My exhaust hardware is all rusted so was hoping not to touch them, at this point.

Might end up removing the diff. I had bought the necessary seals years ago and never got around to changing them. Fluid levels were never an issue, so the project stayed on the bucket list.

Any additional advice to NOT cross-thread bolts? Was just planning to use my jack and line up the holes, completely screw in bolts by hand (all the way), and back out with the slightest resistance. Any tips or tricks, angles, etc?

Also, understand I should do front and then rear bolts?

[Flat-Six]

Any additional advice to NOT cross-thread bolts? Was just planning to use my jack and line up the holes, completely screw in bolts by hand (all the way), and back out with the slightest resistance. Any tips or tricks, angles, etc?

Also, understand I should do front and then rear bolts?

I installed the rear two bolts first while supporting the diff with the floor jack, this provides additional support and alignment of the diff to assist the install of the front bolt. Then (as I stated above) I used a 2x4 (actually it was prob the 2x6 that the diff was resting on top of the floor jack) to very carefully position the diff in alignment with the front bolt to avoid cross threading. You can also slide in a crow-bar on the side if needed for additional alignment. This was VERY easy, and allowed me to carefully thread the bolt in by HAND to ensure I was not cross-threading. This is how I did it. I am sure there are many other successful ways to do this.

BTW: I've got some pic's showing the tool configuration for installing the front bushing. If it would help, PM your email and I'll send them to you.

[oceansize]

The thread you referenced shows the diff completely removed. How were you able to set up your tool with diff in place?

Also, still assume you have to remove exhaust (or lower), heat shield, disconnect drive shaft and two output shafts, and rear sway bar. Please confirm.

LoL. I meant to type "can't" be removed and instead typed "can". Changed my post.

[Steve]

I removed the diff and used my RTAB tool to do the front bushing. I used a large socket to first pull the core of the old bushing out and then used a chisel and hammer to cut the metal ring around it and then hammered it out. I then used the rtab tool to push the new bushing in after leaving it in the freezer. I ended up bending the metal threaded rod on my tool, but I just got another one at ace hardware as it's a common size.

Overall, this was one of the more frustrating jobs that I've done on my car, but it made a huge difference once done so it was worth it.

Also, I'm impressed that your state inspection caught this, ours are not detailed at all.

[oceansize]

I removed the diff and used my RTAB tool to do the front bushing. I used a large socket to first pull the core of the old bushing out and then used a chisel and hammer to cut the metal ring around it and then hammered it out. I then used the rtab tool to push the new bushing in after leaving it in the freezer. I ended up bending the metal threaded rod on my tool, but I just got another one at ace hardware as it's a common size.

Overall, this was one of the more frustrating jobs that I've done on my car, but it made a huge difference once done so it was worth it.

Also, I'm impressed that your state inspection caught this, ours are not detailed at all.

I had read so many horror stories on this job and I was literally done in less than 10 minutes (the actual press part). I was doing a complete rear end refresh so everything was out. One of those moments where you just know you got lucky.

But OP, I highly recommend using the new bushing, in combination with whatever tool, to press out the old bushing, worked beautifully.

[Steve]

I had read so many horror stories on this job and I was literally done in less than 10 minutes (the actual press part). I was doing a complete rear end refresh so everything was out. One of those moments where you just know you got lucky.

But OP, I highly recommend using the new bushing, in combination with whatever tool, to press out the old bushing, worked beautifully.

Yes, if I had the proper tool it would have been much easier, no doubt. Kind of like the RTAB horror stories you hear about from when people don't buy the tool.

My front diff input seal was also leaking, which meant everything in the area was coated in grease which only made things more miserable.

[heinzboehmer]

Any additional advice to NOT cross-thread bolts? Was just planning to use my jack and line up the holes, completely screw in bolts by hand (all the way), and back out with the slightest resistance. Any tips or tricks, angles, etc?

Also, understand I should do front and then rear bolts?

Yeah just make sure the diff is as closely aligned to the bushing hole as possible and make sure everything can be threaded in/out by hand before torquing.

This is how it should be installed according to TIS (https://www.newtis.info/tisv2/a/en/e...-drive/4VCEnM1 ):

Insert front bolt
Insert rear bolts
Torque front bolt to 200 Nm
Torque rear bolts to 20 Nm + 90°

[oceansize]

Also when the diff is out thread the bolt in once to get a feel for the type of resistance, or lack thereof, that you should expect.