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  1. #1
    Join Date
    Jun 2018
    Location
    Vermont
    Posts
    49

    Default Replaced a rear diff in a friend's 04 xc70, here's how it went...

    His rear diff was howling, we found it near empty and leaking from a side seal, got a great used one from a local yard, got the fitler kit and put fresh fluid and filter in, now for removal, we found we don't have to drop the whole rear carrier assembly.

    Well after scowering the interwebs and YouTube for some help and instructions, and finding very little, we tore into it.

    Up on multiple jackstands... Used 6 to be safe.


    Wheels off, caliper off, bracket off, rotor off. Exhaust off from cat back, Easy stuff.

    Removed wheel bolts and bearings. Removed parking brake backing plate and cable.

    Removed trailing arms, and control arms.

    Removed both strut assemblies, one bolt in the cargo area, two body mounts, one arm bolt.

    Removed sway bar. Could not get the knuckle separated from the upper aluminum arm.

    Removed the 8 bolts for the rear cover housing the diff.

    Removed both axles. This part is 2 person. I was banging, pulling prying, everything I could think of, nothing worked. With an assistant pulling, they popped out In 3 seconds flat, we felt dumb.

    Then We came to the realization that we did not need to drop the whole thing, as random threads suggested... Took off the driveshaft bolts and the one bolt that held the rear end in... Lowered it with a jack.

    Installed the new one. Almost done with reassemblely.


  2. #2
    Join Date
    Jun 2018
    Location
    Vermont
    Posts
    49

    Default

    Quote Originally Posted by Hamfist View Post
    His rear diff was howling, we found it near empty and leaking from a side seal, got a great used one from a local yard, got the fitler kit and put fresh fluid and filter in, now for removal, we found we don't have to drop the whole rear carrier assembly.

    Well after scowering the interwebs and YouTube for some help and instructions, and finding very little, we tore into it.

    Up on multiple jackstands... Used 6 to be safe.


    Wheels off, caliper off, bracket off, rotor off. Exhaust off from cat back, Easy stuff.

    Removed wheel bolts and bearings. Removed parking brake backing plate and cable.

    Removed trailing arms, and control arms.

    Removed both strut assemblies, one bolt in the cargo area, two body mounts, one arm bolt.

    Removed sway bar. Could not get the knuckle separated from the upper aluminum arm.

    Removed the 8 bolts for the rear cover housing the diff.

    Removed both axles. This part is 2 person. I was banging, pulling prying, everything I could think of, nothing worked. With an assistant pulling, they popped out In 3 seconds flat, we felt dumb.

    Then We came to the realization that we did not need to drop the whole thing, as random threads suggested... Took off the driveshaft bolts and the one bolt that held the rear end in... Lowered it with a jack.

    Installed the new one. Almost done with reassemblely.

    Annnd, the diff won't work. Many codes in the dash from brake failure, to transmission errors to engine electrical...

    Rear tires won't turn at all.

    Just like my stereo install, I did not disconnect the battery before unhooking the diff and installing the new one.

    I'm guessing I gotta get that vida and proceed with that.

  3. #3
    Join Date
    Oct 2011
    Location
    Northshore - Great Lakes
    Posts
    803

    Default

    2001 V70XC - Nautic Blue/ 2-tone Sand/ Premium/ Instant MPG 12 - 63/ Pirelli P4 12/32" - 740/ Duracell 48/ MOBIL-3309/ Pennzoil EURO 5W-40/ Zimmerman Z-coated/ Akebono/ 190K-mi/ Great Lakes

  4. #4
    Join Date
    Jun 2018
    Location
    Vermont
    Posts
    49

    Default

    Quote Originally Posted by Xheart View Post
    No it's the whole rear diff assembly.

  5. #5
    Join Date
    Aug 2017
    Location
    Pleasanton CA USA
    Posts
    412

    Default

    I'm confused. The rear differential is a passive gearbox in the transverse rear axle - it has no electronics. It's closer to the rear left wheel. This rear diff gearbox
    has the job of allowing the two rear wheels to rotate at different speeds while going around corners.

    The Haldex AWD coupler is at the back end of the propeller shaft, and does have computer interface. It has the job of responding to any slippage in the front wheel drive,
    and "clutching in" the rear wheel axle to deliver power in response.

    It sounds like you replaced the Haldex??

    What were the initial symptoms?

  6. #6
    Join Date
    Aug 2018
    Location
    NH
    Posts
    13

    Default

    Did you put the Haldex (electronic box) that was with your car originally in with the new differential? Or did you get a new Haldex unit with the new rear end? Some people remove the drive shaft and convert this to a FWD car. I'm wondering if you did this would your problems go away or are you fighting multiple problems? I'll look at VIDA later and post the instructions if you need them.

  7. #7
    Join Date
    Oct 2011
    Location
    Northshore - Great Lakes
    Posts
    803

    Default

    2001 V70XC - Nautic Blue/ 2-tone Sand/ Premium/ Instant MPG 12 - 63/ Pirelli P4 12/32" - 740/ Duracell 48/ MOBIL-3309/ Pennzoil EURO 5W-40/ Zimmerman Z-coated/ Akebono/ 190K-mi/ Great Lakes

  8. #8
    Join Date
    Feb 2013
    Location
    Boston, MA
    Posts
    1,155

    Default

    If you read the codes with DiCE/VIDA and you see CEM-1A64 "Communication with AOC control module. Signal missing", even in a yellow state, you need to take DEM (Haldex control module) apart and see if it can be fixed. Noises from DEM causes software malfunction in TCM (transmission module), without TCM there's no immobilizer quorum, engine can't be started. This was sporadic in my case.

    There's a weak seal around connectors that eventually fails and let dirt/water to get in. Depends on how lucky you are, you may be able to fix your DEM. Otherwise get a working donor DEM, take it apart, clean, seal with fireplace sealant (it remains flexible after drying and tolerates high temperatures). Don't seal 3 little holes between sockets!











    2002 V70 (sold)
    2005 XC70 (Telos Road took it. Did a chassis swap)
    2016 XC60

  9. #9
    Join Date
    May 2012
    Location
    Calgary, Alberta
    Posts
    603

    Default

    Quote Originally Posted by Hamfist View Post
    Annnd, the diff won't work. Many codes in the dash from brake failure, to transmission errors to engine electrical...

    Rear tires won't turn at all.

    Just like my stereo install, I did not disconnect the battery before unhooking the diff and installing the new one.

    I'm guessing I gotta get that vida and proceed with that.
    Is the driveshaft/propeller shaft turning?

  10. #10
    Join Date
    Jun 2018
    Location
    Vermont
    Posts
    49

    Default

    Quote Originally Posted by ssicarman View Post
    Is the driveshaft/propeller shaft turning?
    The whole assembly, from the coupling for the driahaft to where the axles plug in.

    The driveshaft spins, yes.

    We swapped nothing external or internal on the assemblies, just dropped the whole assy, and installed the new on, hooked the driveshaft back up and put the half shafts in, and suspension arms, etc.

    We did just take the coupling out of the old one and was going to swap a known working one out of the car, (diff was growling, ring, maybe pinion, not sure) into the new(used) diff assembly, but I thought software issues might be first, instead of more skinned knuckles.

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