subidoo Posted August 14, 2015 Share Posted August 14, 2015 (edited) Hello ALL! I just got a 1996 Impreza/Outback, AWD Automatic. The rear differential is making a terrible clunking noise and on inspection, the case itself is cracked. The noise is for sure coming from inside the differential, which sounds like stuff is broken within. My concern is a couple things. 1) The previous owner had replaced this differential with a used one just 4 months ago 2) What leaked out looks like Tranny fluid, not Gear oil. 3)The hood sticker says that the engine is a 1.8L, but my research says that 1996 Automatic AWD's didn't come with 1.8's, and only 2.2's and 2.5's. (Hood may have been replaced? Also, He may have gotten the wrong ratio differential, like for a 1.8L?). My motor stamp says EJ22, which is a 2.2L, right? 4) I found another differential with axles complete for $200.00, out of another 96 Impreza Automatic, and will arrive today, but I have no idea on how to do the job, nor can I find a post on the procedure. (Although I am mechanically inclined enough to 'figure it out', eventually, lol). 5) My research says that the differential Gear Ratio should be a 4.11, correct? How can I determine if this matches the transmission, etc? 5) I still need to find what caused the Original problem, (like tire size mismatches, maybe a binding wheel hub, etc All that said, any help on the above would be Mucho Appreciated ! ! ! -Subidoo Edited August 14, 2015 by subidoo Link to comment Share on other sites More sharing options...
john in KY Posted August 14, 2015 Share Posted August 14, 2015 Remove the cover plate, count both the number of pinion and ring gear teeth and then divide the ring gear number by the pinion number. Because the differential was just removed/installed, at least you will not have to fight rusted bolts. Link to comment Share on other sites More sharing options...
subidoo Posted August 14, 2015 Author Share Posted August 14, 2015 (edited) That's good info. However, since I have a 4:11 differential, (with the axles), replacement coming in today out of the same year and model, I wouldn't think to bother with the 'bad' one, except just removing it. What really concerns me is if the one being installed today is a match to the rest of the drive train/transmission/final drive, and 'HOW' do I check that? Does the tranny's I.D. tag indicate what Ratio it is putting out to the rear end? The tag on the bellhousing in front of the starter says; TZ102ZA4B, F. I believe this means it has a 4:11 Ratio to the rear end ??? Jeez, I hope so! Also, does anyone have the DIY on removing the rear differential and rear CV axles? Thank You ! -Subidoo Edited August 14, 2015 by subidoo Link to comment Share on other sites More sharing options...
Fairtax4me Posted August 14, 2015 Share Posted August 14, 2015 (edited) The hood should have a VIN sticker on it somewhere that you can compare to the VIN on the dash. Auto Trans ratio for an AWD should be 4.11. If there was ATF in the rear diff, that's why it exploded. The diff needs GL5 spec hypoid gear oil. You really should check the front differential oil as well if you haven't already. Axles can be a nightmare if the outer joints are seized in the hubs. When I swapped the 4.11 diff into my legacy I didn't even unbolt any of the rear suspension. Just popped the axles out of the diff and rocked it side to side as I was lowering it out to get the axles out of it. You might want to just drop the diff out first and check the splines and the bearing surface on the axles before you decide to totally remove them. If they're not scored just leave them in the hubs. Rear diff. Remove the exhaust heat shield. Remove the rear section of the driveshaft to the diff and slide it forward out of the way. Remove the 4 bolts that hold the lower crossmember braces under the inner axle joints. Use a prybar braced against the bottom rear bolt on the bearing retainer ring to pop the axles loose from the diff. The easiest way is to put pressure on the bar and smack it with a big hammer to jolt the axle loose. Just pull them out far enough that the clips won't re-engage. Remove the 4 nuts that hold the diff in the cradle. Remove the 2 nuts on the studs that go through the diff support bushings on the back of the cradle. If the studs are not majorly rusty the whole thing will slide forward and you can lower the diff down with a floor jack. Once it's lowered about 6 inches you'll have enough room to slide it one way or the other and pull the inner axle joints out of it. An extra pair of hands helps. If you don't have a helper use a ratchet strap or zip ties or bungee cord or something to help secure the diff on top of the jack head. Its awkward and fairly heavy and will want to roll or slide around. If the bearing surfaces on the axles are scored then they'll need to be replaced. (the part with the helical cut groove for oil) If they're not scored or damaged clean the old oil off and any shavings or other metal and lubricate them with clean gear oil before putting them into the new diff. Edited August 14, 2015 by Fairtax4me Link to comment Share on other sites More sharing options...
porcupine73 Posted August 14, 2015 Share Posted August 14, 2015 Possibly useful: Correct Axle Ratios CorrectInfo.pdf Link to comment Share on other sites More sharing options...
subidoo Posted August 14, 2015 Author Share Posted August 14, 2015 Wow,thanks for all those helpful hints. I just finished the job in just over two hours, and she cruises down the road beautifully! It was nice Not removing the axles from the hubs, and the splines were still in great condition. Overall, it was a piece of cake job and the 4:11 differential was indeed correct. This forum Rocks!!! Thank you again! -Subidoo Link to comment Share on other sites More sharing options...
Fairtax4me Posted August 15, 2015 Share Posted August 15, 2015 Awesome! 2 hours is pretty quick! Link to comment Share on other sites More sharing options...
porcupine73 Posted August 15, 2015 Share Posted August 15, 2015 Nice, two hours, how much pepsi did you drink? Link to comment Share on other sites More sharing options...
subidoo Posted August 24, 2015 Author Share Posted August 24, 2015 Lol,just got very focused, had air tools, and perhaps a bit of luck! 1 Link to comment Share on other sites More sharing options...
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