Rear Differential removal diy guide?

[jacobsen]

Any one have a link to a write up for the rear diff removal? All I can see is 2 bolts to a bracket from under the car, the axles and the drive shaft.

[old guy]

I don't have any DIY links but it is really pretty straight forward. The one thing that is very important is to mark the drive-shaft's relative position to the differential flange. Otherwise you may cause an imbalance that will cause you a lot of grief.

[Spike00513]

Workshop-manuals.com

Bentley Service Manuals

ELSAwin/ERwin

------------------

Factory procedure is to clean out the flange threads when you remove it, by using a matching size thread tap. This is to clean out the old red loc-tite.

Bolts are one-time use, but I've re-used them without problems.

Be careful with the 3 bolts that attach the carrier/bushing piece to the diff itself. You may want to support the diff a little from underneath with a jack, while working on those bolts. The weight of the diff can mess up their angle, resulting in stripped threads on the diff. That is not fun, because repairing this damage entails diff removal and Time-Sert repair kit work.

Also, note the orientation of the rubber vent on top. Don't stand the differential straight up or upside down, because fluid will come out of that vent and make a mess on your floor. Set it down on the floor in the same orientation that its in when installed.

[jacobsen]

I don't have any DIY links but it is really pretty straight forward. The one thing that is very important is to mark the drive-shaft's relative position to the differential flange. Otherwise you may cause an imbalance that will cause you a lot of grief.

I assumed it was balanced in all directions. I did not mark the axle position when I did the clutch and I haven't had a vibration. But this is a good suggestion, I'll do that. I see the diff has a bracket of sorts, a large triangular shaped piece that has 2 bolts either side attaching it to the body, other than that I see the axle bolts, and the drive shaft bolts. Kind of thought there should be more than that. But hey, if that is how it is then so be it, looks like tomorrow I'll be taking the job on. I'll remove the diff, clean it off since it has some thick greasy puss on it. Pop the flanges off and replace the seals, I bought all the seals for it a while back... Just never got around to doing it. I refilled a half liter of motul 300 in it and didn't notice a massive difference. I wonder.... If some one over filled it previously would that cause it to leak? I'd say with the half liter I added perhaps as much as a 3rd of that leaked out while trying to fill it at that awkward angle. I'm a nut and the fact that it is dirty is enough for me to want to clean it.

[Spike00513]

^I cleaned mine by masking off sensitive parts such as axle flanges (I duct taped plastic bags over them). I used Castrol Super Clean + old toothbrush, then hosed/rinsed it off.

As for the seals, I hope you are using all the necessary parts. I believe you're also supposed to use some sort of grey grease to keep moisture from getting in, which Audi deems necessary maintenance for when the old stock stuff dries out. In other words, if you remove the diff, you will see on the front driveshaft flange, there's a bunch of grey goo. That's what I'm talking about. If you somehow remove it, I'm guessing you need to replace the grease. This is one reason I mask the flanges off with duct tape and plastic bags - so that I don't end up washing off the grease.

[diagnosticator]

^I cleaned mine by masking off sensitive parts such as axle flanges (I duct taped plastic bags over them). I used Castrol Super Clean + old toothbrush, then hosed/rinsed it off.

As for the seals, I hope you are using all the necessary parts. I believe you're also supposed to use some sort of grey grease to keep moisture from getting in, which Audi deems necessary maintenance for when the old stock stuff dries out. In other words, if you remove the diff, you will see on the front driveshaft flange, there's a bunch of grey goo. That's what I'm talking about. If you somehow remove it, I'm guessing you need to replace the grease. This is one reason I mask the flanges off with duct tape and plastic bags - so that I don't end up washing off the grease.

Spike, it is amazing how much you have learned since you first start participating here on the forum. :>)

[old guy]

I assumed it was balanced in all directions. I did not mark the axle position when I did the clutch and I haven't had a vibration. But this is a good suggestion, I'll do that.

If you look closely there should be paint marks from the factory that indicate the original alignment. There will be two dots of paint that should be aligned.

[jacobsen]

Alright I'll check on this grey grease? It must be a waterproof grease maybe similar to boat grease to repel water, I don't plan to remove any of the grease, I know when I did the clutch I packed some cold temp grease around the axle where it met the flange just to be sure. Got a part # or any thing more specific? I'm not sure if I have a tap for that... hmm... I'll get some red locktite, check. How did you hold the flanges in place to unscrew the bolts? I have a transmission jack I got when I did the clutch, the transmission must weigh 150 pounds. Wonder what the diff weighs? I'll try not to let the carrier bushing bend. And thanks for the heads up oldguy. Wish I could run ETKA on my windows 8 craptop. I'm going to try a virtual machine to see if I can get it to run...

[Spike00513]

I'd guess the diff is 40 pounds. I can carry it by hand. But to remove it, because you're under a car and would rather not carry it, a regular hydraulic jack works well. I use a hockey puck for a jack pad.

You don't need ETKA. Google "parts cats" and click the first link that days something about "teilekatalog".

New bolts come with red loctite on them, so if you ordered new ones, you won't need them. Bentley says that not cleaning out the threads with a thread tap can result in the bolt locking in there too tight, and breaking next time you remove it.

You can break the axle flange bolts loose in many ways, such as by having a helper hold down the brake while you break a few loose, then let off while you spin it (in neutral) to gain access to the other bolts. Then brake again. Or have it in gear and e-brake on, I think.

Part number for grease is G 052 128 A1

[jacobsen]

Well I tried every vw and audi dealer around here and no one has this g052128a1 ...They have some a couple of them had some old tubes that were opened for shop use and would sell them to me for half off but.. Eh... They said they were water separated and I'm not sure it sounds critical? Could any grease do? It's blue in color and is for sealing the radial shaft, wonder if silicone grease would be alright?

[jacobsen]

One of the techs said he saw a diagram with a Loctite 5970 on it next to the seal. Is that what I'm looking for?

That's probably to cure the actual flange plate/cover thing to the diff housing? Not this special grease...

[jacobsen]

I was not able to remove the drive shaft from the differential. So the diff is just hanging from the CV joint... :| It took forever to remove the diff from the car and it's still not disconnected from the drive shaft. My advice is if you have a small leak, just clean it once and a while. This is a nightmare, I wish I hadn't taken this job on. Now I'm worried that I may have messed up or bent my CV joint bearing cage because while I was attempting to remove the diff from the car it bound up and hung in the air for several seconds a few times while I tried to work the cv to a pint where it would flex enough to let the rear of the diff rest on the ground. I replaced the leaking seal, I plan on doing the other one since it's easy to do, there was no red loctite on the flange bolt and it came loose pretty easily. I did break the dust shield when I pried the old seal out, I'll have to get a couple of those. It took a hammer claw to pry the old seal out. It's getting cold up here... wanna get this done asap, my next window is this weekend. Hopefully all goes smooth.

[onlyjuancannoli]

If you look closely there should be paint marks from the factory that indicate the original alignment. There will be two dots of paint that should be aligned.

Mega old bump.

Oldguy, do you know if this will be on both the differential, and transmission?

[old guy]

Differential only.

[onlyjuancannoli]

Think this might be my issue. Didn’t find paint, but I found a mark I believe is an alignment mark on the diff. I thought the driveshaft was balanced though. Why would it matter if it wasn’t lined up?

[old guy]

Think this might be my issue. Didn’t find paint, but I found a mark I believe is an alignment mark on the diff. I thought the driveshaft was balanced though. Why would it matter if it wasn’t lined up?

I assume Audi had a reason to mark the alignment. Otherwise why bother?

[Spike00513]

Think this might be my issue. Didn’t find paint, but I found a mark I believe is an alignment mark on the diff. I thought the driveshaft was balanced though. Why would it matter if it wasn’t lined up?

you can make alignment marks with a Forney paint marker from Amazon or Ace Hardware any time you remove a propshaft

[onlyjuancannoli]

you can make alignment marks with a Forney paint marker from Amazon or Ace Hardware any time you remove a propshaft

Yeah, I did for some stuff but this is loooooooong past that point haha. I've been trying to diagnose a vibration since September.

[BumblebVR6]

I assume Audi had a reason to mark the alignment. Otherwise why bother?

Hmm..I just installed an aftermarket driveshaft and am noticing a bit of vibration around 45-50mph. Feels more up front in the steering or wheels though. I'm going to swap wheels and see if it changes. Don't recall the new driveshaft having any marks, but I didn't look for any either. How about the center support? Has oval holes that let you mount the bracket either direction .5" or so. That shouldn't cause any extra wear on the center bearing if not in the same spot as oem would it?

[cleoo]

Searched all over for a DIY guide to remove the rear differential. Youtube wasn’t helpful.

I have the thump slam of the rear differential when my RPMs go below 2000 and I slow down past 40 MPH in regular mode (Sport mode is at a higher gear when I slow down around 40 and doesn’t thump.) I can tap the accelerator to bring up the revs a little to soften the thump. Happens around 65MPH also.

I’d like to replace it, but I can’t access the top Hex bolt because it’s blocked by the subframe.

I can’t access the larger bolts above because of the sway bar.

Any tips on removal? I’d appreciate it.

[Dr.B6Banter]

Searched all over for a DIY guide to remove the rear differential. Youtube wasn’t helpful.

I have the thump slam of the rear differential when my RPMs go below 2000 and I slow down past 40 MPH in regular mode (Sport mode is at a higher gear when I slow down around 40 and doesn’t thump.) I can tap the accelerator to bring up the revs a little to soften the thump. Happens around 65MPH also.

I’d like to replace it, but I can’t access the top Hex bolt because it’s blocked by the subframe.

I can’t access the larger bolts above because of the sway bar.

Any tips on removal? I’d appreciate it.

I'd remove the diff mount with the diff. That's how I did it after encountering the same problem you faced. Unless you have a low profile Allen key that's strong enough to not bend, you'd be hard-pressed to get that last bolt out.

I've highlighted in red where the differential mount bolts into the subframe. It's a long bolt and nut (18mm maybe). It's tight to get at the bolts since it's right by the swaybar but definitely doable as I did it with basic tools. I didn't have a flared 18mm wrench to access the recessed bolts so I just got by with an 18mm socket while holding the other end with a normal wrench.

Capture.jpg

[Gosser]

Searched all over for a DIY guide to remove the rear differential. Youtube wasn’t helpful.

I have the thump slam of the rear differential when my RPMs go below 2000 and I slow down past 40 MPH in regular mode (Sport mode is at a higher gear when I slow down around 40 and doesn’t thump.) I can tap the accelerator to bring up the revs a little to soften the thump. Happens around 65MPH also.

I’d like to replace it, but I can’t access the top Hex bolt because it’s blocked by the subframe.

I can’t access the larger bolts above because of the sway bar.

Any tips on removal? I’d appreciate it.

I dont think your rear diff is the problem, sounds like for of a mount that a diff. These diffs arent known to go bad. But to remove the diff, just remove the sway bar bracket and swing it down, then you'll have all the access. An off set box wrench helps to hold those recessed bolts. I prefer to take the diff our with the large bracket. Or drop the rear subframe bolts by an inch and you can get the top allen, but they can be a bit of a pain to realign.

[Dr.B6Banter]

I dont think your rear diff is the problem, sounds like for of a mount that a diff. These diffs arent known to go bad. But to remove the diff, just remove the sway bar bracket and swing it down, then you'll have all the access. An off set box wrench helps to hold those recessed bolts. I prefer to take the diff our with the large bracket. Or drop the rear subframe bolts by an inch and you can get the top allen, but they can be a bit of a pain to realign.

Yeah aligning up the diff and bracket back into the subframe is far easier than trying to line up the diff to the bracket.

That's also a good point about the diff likely not being the issue. I didn't read the post entirely but now that I have it seems like more of a mount issue.

The fron the of the diff is mounted to the subframe with 3 bolts, and if those back out or of the bushing in the mount is worn then you would hear loud thumps from the rear end during on/off throttle transitions. I didn't use Loctite on those bolts during my auto to manual swap and after a month of driving, they backed out and I started hearing very loud thumps/ slams from the rear end only to see the front of the diff hanging down an inch lower than normal. A worn bushing would likely cause the same symptoms.

Capture.jpgCapture2.jpg

[cleoo]

I’ve been reading about the diff mount being a source of the problem, but when I checked the side diff mount it was securely mounted and didn’t appear to have cracks in the bushing.

However, there was quite of play on the differential when I rotated the shaft left and right, probably 3-5 degrees. I compared it to a differential I was going to replace it with and very little play, maybe 1 degree.

From a cold start, when I put it in either Drive or Reverse, I feel the thump—the whole car shakes.

[cleoo]

I also bought a side diff mount to replace the old one but that’s not as easy to pull out either. The large single bolt mounted to the frame is difficult to get to. Tips to get to that?

Looks like the bottom hex bolts are fairly easy but the differential will kinda hang from the rear mount which seems like a lot of weight for those rear bushings.

[Dr.B6Banter]

I also bought a side diff mount to replace the old one but that’s not as easy to pull out either. The large single bolt mounted to the frame is difficult to get to. Tips to get to that?

Looks like the bottom hex bolts are fairly easy but the differential will kinda hang from the rear mount which seems like a lot of weight for those rear bushings.

Yeah, I'd suggest supporting the diff with a jack or something, then undo the 3 hex bolts on the front of the diff, then move back to undo the 2 large bolts holding the diff carrier to the subframe. Then once the diff is out (assuming you've already unbolted the driveshaft carrier bearing and front of the driveshaft), you should have room to get at the bolt holding the front diff mount to the chassis.

[cleoo]

Oh, wow. If I'm going that far with removing the differential, I might as well replace the diff if it's that involved. Is there a simpler method than doing all that? Like just the 3 hex bolts and the top bolt (if I can somehow get to it). Or is this the only way? Well, I guess I wouldn't have to remove the axle bolts in this scenario.

I appreciate the helpfulness you and Gosser have shown.

[Dr.B6Banter]

Oh, wow. If I'm going that far with removing the differential, I might as well replace the diff if it's that involved. Is there a simpler method than doing all that? Like just the 3 hex bolts and the top bolt (if I can somehow get to it). Or is this the only way? Well, I guess I wouldn't have to remove the axle bolts in this scenario.

I appreciate the helpfulness you and Gosser have shown.

Only way I can think of getting to the front mount's chassis bolt with the diff still in the car would be to just undo the 3 hex bolts on the front of the diff and let it hang down. That may give you enough room to reach around the driveshaft and get a socket or bit on the last bolt for the mount.

[cleoo]

Thanks, I’ll give it a try after I get some offset wrenches.

[ChatYTB]

I assume Audi had a reason to mark the alignment. Otherwise why bother?

IN reality some are marked and some aren't and it is VW states in manual :

check whether there is a marking (paint dot) on flexible cou‐
pling and on flange for propshaft on rear final drive -arrows-.
–
If there is no marking, mark position of flexible coupling relative
to flange for propshaft on rear final drive.

[lowlife89]

What happens when you fit a propshaft that the breakers removed without marking?

[Dr.B6Banter]

Assuming you're refering to unbalanced driveshaft leading to vibrations? I'm not sure how much if an issue that is as I've had the trans in and out several times without marking the driveshaft clocking and don't notice any issues. Ensuring the flanges are fully seated into the cups and center carrier bushing not being worn seems to have more impact than driveshaft clocking, at least for me.

[lowlife89]

I'm replacing mine with one from the breakers. Hopefully without any vibrations. Thanks!