gbhrps Posted July 20, 2011 Share Posted July 20, 2011 Gentlemen, The patient is an 07 OBW LTD with 2.5/auto and 130 000 km (78 000 mi). A rear end noise/howl (constant, does not change in pitch, but varies in volume at speed) has been identified as coming from the rear differential. ( both rear hubs replaced within the last month) I will remove and replace the differential myself. Down time is not a problem, as I have 5 other cars to drive in the meantime. Within the next year I will trade the car, I suspect. One option is to drop the diff at a Subie dealer and let them find the source of the noise and repair it. The other is to source a used diff from a wrecker. (The chances of getting a used diff with a problem that would show up in a year, I predict as very slim.) The last time I visited my local Subie dealership, their shop rate was $92/hour. What would you do if you were in my shoes? Link to comment Share on other sites More sharing options...
idosubaru Posted July 20, 2011 Share Posted July 20, 2011 subaru rear differentials almost never fail, extremely rare. positively identify it first. the good news is that if it is a rear differential failure it should be really inexpensive to buy a used one and more than likely the used one will last 300,000 miles if it's never run low on gear oil. they just never fail. i'm nearing 200,000 miles on 3 of my daily drivers and fully expect all of them to go to 300,000 and i'd bet a lot money the rear diffs won't have any issues making that. all that to say - buy used. even folks driving 1980's subaru almost all have the original rear diffs, they just don't fail. drain the fluid and check for chunks/pieces. if it's making noise there should be evidence in the fluid. or if it doesn't have any fluid that might help you decide too! rear differentials aren't that hard to replace at all if you're up to doing it yourself and there's certainly nothing special about Subaru's so finding a lower hourly rate shop to do it is a great choice in this case. Link to comment Share on other sites More sharing options...
gbhrps Posted July 21, 2011 Author Share Posted July 21, 2011 grossgary, Just what I wanted to hear. I suspected that putting in a used rear end was going to be the way to go. And, yes, I'll do the job myself. Thanks for taking the time to pass on the advice! It is much appreciated. Link to comment Share on other sites More sharing options...
idosubaru Posted July 21, 2011 Share Posted July 21, 2011 haven't dropped a rear diff in a newer gen yet (because they rarely fail), but i have installed clutch type locking rear diffs on older gen soobs. 4 12mm bolts disconnected the driveshaft. about 3 bolts usually hold the diff in place (one huge one up top and two on the back) 7 bolts/nuts and the older ones come out. with those done the diff will actually hang down off the car with just the axles still attached. i've swapped diffs but doing nothing more than listed above. with the diff dropped down there was enough room to knock a pin out, pull one axle, then do the same on the other side. just pull the axle off the diff, no need to remove it from the car. yours might differ from that, but it won't be by a whole lot, it's not hard. yours may have axles that slide into the diff though and just pop in and out, i've seen EJ's have both style so not sure what your 07 will have but both are equally simple. it's just annoying working on the car and the diff becomes bulky due to limited working space under there. Link to comment Share on other sites More sharing options...
edrach Posted July 21, 2011 Share Posted July 21, 2011 Definitely swap the rear diff. Easiest thing to do and not an expensive replacement to try and eliminate the problem. Especially if you do the work yourself. Odd that the rear diff would go. I have to ask (my apologies) but are both tires on the rear the same size, type and air pressure? Link to comment Share on other sites More sharing options...
gbhrps Posted July 22, 2011 Author Share Posted July 22, 2011 edrach, The tires are all OEM's that came on the car when new (I swap late in the fall with another set of rims that have snows). All the tires have the same tread depth with no unusual wear patterns, and all have the recommended air pressures and are checked weekly. (My wife says that I'm too fussy and particular.) Link to comment Share on other sites More sharing options...
edrach Posted July 22, 2011 Share Posted July 22, 2011 edrach, The tires are all OEM's that came on the car when new (I swap late in the fall with another set of rims that have snows). All the tires have the same tread depth with no unusual wear patterns, and all have the recommended air pressures and are checked weekly. (My wife says that I'm too fussy and particular.) It pays to be fussy. Cost without labor for a new viscous coupler on a manual tranny is around $575. I haven't a clue what it costs on an automatic. Link to comment Share on other sites More sharing options...
johnceggleston Posted July 22, 2011 Share Posted July 22, 2011 subaru rear differentials almost never fail, extremely rare. especially if they are not leaking gear oil. Link to comment Share on other sites More sharing options...
gbhrps Posted July 30, 2011 Author Share Posted July 30, 2011 Gentlemen, After more research of the problem, I discovered that the rear end doesn't have any leaks, and that the fluid level is correct and the fluid looks virtually new. So, I got the car up on a hoist at an independent garage and had the mechanic use a stethoscope on all moving parts on the rear of the car. Both rear hubs that had been replaced recently were noisy, particularly the driver's side. After their replacement today with a premium hub replacement (non Subie) the noise problem has been fixed. For those who had said that they had never heard of a Subie rear differential going bad .... well, I guess you still haven't. Thanks for all of the input guys! Link to comment Share on other sites More sharing options...
idosubaru Posted July 30, 2011 Share Posted July 30, 2011 nice job, glad you finally got it nailed. you were wise to check into as i first suggested, i'm not surprised you found it to be something else. so - how were the hubs replaced last time? were those used hubs or did someone press in new bearings? Link to comment Share on other sites More sharing options...
gbhrps Posted July 31, 2011 Author Share Posted July 31, 2011 grossgary, I'm embarrassed to say that the less than one month old hubs that were discovered to be noisy, were brand new, an internet purchase, and were made in China. Total cost to my door for the two of them was $110.48. That should have been a heads-up. I must say that they looked perfectly fine out of the package and felt good when hand turned prior to installation. I installed them myself and torqued everything according to specs. They were noisy from the start, and not much of an improvement from the original hubs that I removed. Anywho .... the new hubs have solved the problem. As far as seeking a refund on the internet purchased hubs, I won't bother. I was trying to cheap out a fix for a car I'm going to trade in a few months' time. I'm sure that the return shipping, the phone calls, and the resulting runaround won't be worth the frustration. I'll chalk it up as a learning experience ... and know better next time. Link to comment Share on other sites More sharing options...
el_freddo Posted July 31, 2011 Share Posted July 31, 2011 (edited) As far as seeking a refund on the internet purchased hubs, I won't bother. I was trying to cheap out a fix for a car I'm going to trade in a few months' time. I'm sure that the return shipping, the phone calls, and the resulting runaround won't be worth the frustration. I'll chalk it up as a learning experience ... and know better next time. Yeah I did the same with a set of drive shafts - they didn't have the proper CV grease in them for starters, so I replaced that after contacting the joint I got them from, mainly for their heads up about the product they were selling (a good friend/business that I don't want to see go under). ~1000km later and the outer joints started to click I've got a new set on the way as replacements, hopefully they'll last longer than the first set! All that said I've heard from several mates now that the problem with the chinese product is that they don't harden the steel properly, instead they cover the required surfaces with the hardened material that can sometimes be picked off with a screwdriver! As for a diff blowing - I've seen one destroyed in a '98 outback while street driving as a daily. Don't know why it went but it completely let go very quickly! Cheers Bennie Edited July 31, 2011 by el_freddo adding a link to back up my blown diff claim :D Link to comment Share on other sites More sharing options...
johnceggleston Posted July 31, 2011 Share Posted July 31, 2011 grossgary, I'm embarrassed to say that the less than one month old hubs that were discovered to be noisy, were brand new, an internet purchase, and were made in China. Total cost to my door for the two of them was $110.48. That should have been a heads-up. since you are confident it was a bad product, how about sharing the name so we can avoid that seller. was it ''dewy cheetum and how''? Link to comment Share on other sites More sharing options...
WoodsWagon Posted July 31, 2011 Share Posted July 31, 2011 As for a diff blowing - I've seen one destroyed in a '98 outback while street driving as a daily. Don't know why it went but it completely let go very quickly! Cheers Bennie I've smoked a few R160's, but it was always parts breaking that took it out. I had one that the spider gears shredded, the cross pin sheared, and it split the carrier where the cross pin goes through. I had a couple I just shredded the spider gears on. I also lost 3 sets of rear transfer gears in the transmissions, and one front diff. I never took that one apart to see what let go, but parts got caught in the ring gear and blew out the bottom of the case. It left a trail of shame (gear oil). That one you linked to looks like either the oil was contaminated with water or sand or something, or it wasn't hypoid gear oil. He mentioned his mechanic had changed all the fluids recently, so possibly he put in manual transmission fluid on accident instead of hypoid gear oil. I have never seen a ring and pinion worn down like that without it being run out of oil. Abuse leads to chipped or missing teeth, not even wear down to nothing. Link to comment Share on other sites More sharing options...
idosubaru Posted August 1, 2011 Share Posted August 1, 2011 Yeah I did the same with a set of drive shafts ....I've got a new set on the way as replacements, hopefully they'll last longer than the first set! i dont' know about your market but over here aftermarket axles are essentially a waste of time. i get used Subaru axles for $33 each and reboot them. there's also a very reputable subaru axle rebuilder that many of us use as well. aftermarket stories like yours are everywhere, i have my own and no longer waste my time on them. Link to comment Share on other sites More sharing options...
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