bluedotsnow Posted March 23, 2012 Share Posted March 23, 2012 can anyone tell me if on a 4eat rear diff if when I spin each tire should it spin the other? one will spin the other ie right will spin the left but left wont spin the right. this is on jack stands by hand. Quote Link to comment Share on other sites More sharing options...
1 Lucky Texan Posted March 24, 2012 Share Posted March 24, 2012 can anyone tell me if on a 4eat rear diff if when I spin each tire should it spin the other? one will spin the other ie right will spin the left but left wont spin the right. this is on jack stands by hand. hmmm, I can tell you on my wife's 03 H6 with weather package, the right rear will spin the left in the same direction (LSD). however, I'm not sure I've tried it the other way. I will try it in April when I plan to do some maintenance. But, I'm not really sure I understand your question. Also, can you be more specific about the vehicle and what direction you expect the wheels to turn? Someone else here may already know how to answer your question. Quote Link to comment Share on other sites More sharing options...
bluedotsnow Posted March 24, 2012 Author Share Posted March 24, 2012 I have a 96 lego l 4eat. I think you do understand or are at least trying to and I really appreciate it! essentially if I put the car on jack stands with the car in p or off I can rotate one of the rear wheels and see the opposite rear tire spinning slightly less rotation than the tire I'm have my hand on. if I then go to the other side of the car and spin the opposite tire by hand the tire I was at first does not move. I can't remember exactly which is right and left that effect or doesn't effect. Quote Link to comment Share on other sites More sharing options...
1 Lucky Texan Posted March 24, 2012 Share Posted March 24, 2012 I have a 96 lego l 4eat. I think you do understand or are at least trying to and I really appreciate it! essentially if I put the car on jack stands with the car in p or off I can rotate one of the rear wheels and see the opposite rear tire spinning slightly less rotation than the tire I'm have my hand on. if I then go to the other side of the car and spin the opposite tire by hand the tire I was at first does not move. I can't remember exactly which is right and left that effect or doesn't effect. Well, some folks say that after about 60-80k miles or so, the rear VLSD is worn out. Likely it depends on other factors like how often the car is on low-traction surfaces etc. Basically, the rear lsd wears out. Dunno why it would behave in an asymmetric manner though. Quote Link to comment Share on other sites More sharing options...
GeneralDisorder Posted March 24, 2012 Share Posted March 24, 2012 You do not have an LSD. When you spin a tire on an open diff when the driveline is attached to something like a transfer case or clutch pack that is not engaged then the power will transfer to either the opposite wheel or the driveline - whichever has less friction. Subaru rear diffs are hard like a coffin nail. Your rear diff isn't broken. If it was it would be making horrific noises and you would know.... GD Quote Link to comment Share on other sites More sharing options...
bluedotsnow Posted March 24, 2012 Author Share Posted March 24, 2012 I will check if the rotation gets transferred to the drive line. I'm glad it seems that rear diff failure is horribly evident because I have had to drive it around and it seems to spin consistently with no noise or vibration. I was told there are mechanical parts like levers in the diff could some of this have stopped functioning due to abuse and not cause noise or vibration just none operation? Quote Link to comment Share on other sites More sharing options...
987687 Posted March 24, 2012 Share Posted March 24, 2012 There are 6 gears and a few bearings in your diff. It's that simple. No levers or magic going on. When my rear diff failed it started out sounding like a wheel bearing, kinda. Then turned into a terrible awful noise. It was an ear retching squealing sound. This happened with about 244,000 miles. Quote Link to comment Share on other sites More sharing options...
bluedotsnow Posted March 24, 2012 Author Share Posted March 24, 2012 sweet I though it was about that simple. very pleased I don't have to replace my rear diff other than when I want to upgrade to an LSD. I know I'm almost beating a dead horse but what could happen if say one or two of the gears on one side had teeth that were ground down from extended use? Quote Link to comment Share on other sites More sharing options...
johnceggleston Posted March 24, 2012 Share Posted March 24, 2012 the problem is either in the transfer clutch or maybe the trans, a fluid issue. before you went to the dealer, did the car have binding in tight turns? Quote Link to comment Share on other sites More sharing options...
bluedotsnow Posted March 24, 2012 Author Share Posted March 24, 2012 no never I thought I might have felt some very slight binding a few days before installing the new parts but I think it was just extra line pressure from limp mode causing what I thought was torque bind, felt it only in the steering wheel. when driving, the car would corner fine and not lurch around as with actual TB but it was slightly harder to turn the car and would not idle itself in a circle. one of the things that really threw me from the start about this car was the rear diff... my first car was a real FrontWD impreza with completely independent rear. when I started driving the lego I think I confused the presence of its non powered rear diff with full AWD. again I was not pushing it and under the impression my inspection mechanic had verified it had at least functional AWD. I have ridden in many manual subaru's but have never been carted around in a 4eat. Quote Link to comment Share on other sites More sharing options...
987687 Posted March 24, 2012 Share Posted March 24, 2012 I know I'm almost beating a dead horse but what could happen if say one or two of the gears on one side had teeth that were ground down from extended use? The ring and pinion gears? They start making bad noises, they don't even have to be very worn to make bad noises. Here's a pic I took the other day when I took mine out. Quote Link to comment Share on other sites More sharing options...
GeneralDisorder Posted March 25, 2012 Share Posted March 25, 2012 I know I'm almost beating a dead horse but what could happen if say one or two of the gears on one side had teeth that were ground down from extended use? It really doesn't work that way. The teeth are case hardened and once the outer surface of the gear teeth is compromised - failure of a complete and total nature will result almost immediately. If its not making horrific gnashing or howling noises or hasn't bound up completely.... It's fine. Seriously when a rear diff goes you will be dragging one or both wheels down the road as they will seize up. GD Quote Link to comment Share on other sites More sharing options...
bluedotsnow Posted March 25, 2012 Author Share Posted March 25, 2012 rofl I think my friend's diff is going out on his impreza obs 5mt. he replaced both wheel bearings and still has rear end noise/vibration. Quote Link to comment Share on other sites More sharing options...
johnceggleston Posted March 25, 2012 Share Posted March 25, 2012 there are a couple of possibilities here: 1/ you had a bad duty c (flashing AT Temp light) and torque bind. this means all the mechanical parts were in place and working before the repair and only the duty c was bad. 2/ you had a bad duty c (flashing AT Temp light) and NO binding, which means that at least some of the mechanical parts were not working properly. in either case, it does not seem as though the repairs were done correctly. either the wrong parts, or not enough parts or an error in the process, or what ever. it is hard to say since we did not drive the car before the repair. but it is for sure you do not have power to the rear wheels now, after the repair? stupid question, how did you determine there is no power going to the rear wheels? you have probably already posted this but i just don't remember. ps: the VSS will/ should throw a code if bad. Quote Link to comment Share on other sites More sharing options...
bluedotsnow Posted March 25, 2012 Author Share Posted March 25, 2012 I asked the dealership to verify 10% power was going to the rear since then I did not have 4 jack stands only 2. I put it on 4 jack stands in d or 1st, 1st has no effect as it should lock the rear more. so if both of the vss are fine the tcu still wont output a specific code if the rear does not get drive? Quote Link to comment Share on other sites More sharing options...
johnceggleston Posted March 26, 2012 Share Posted March 26, 2012 the TCU only reports electrical faults in the trans. if there is a mechanical fault there will be no code. the vss, either one, SHOULD throw a code if bad. have you tried unplugging the TCU and checking the power to the rear then. on an open diff with both wheels in the air, when you turn one wheel by hand, the other wheel should turn in the opposite direction. if it does not, then there is probably some kind of a load on the wheel that is not turning, either a dragging brake or a bad wheel bearing. but if the other wheel does not turn, then the drive shaft should be turning, and it will have less resistance than the other, dragging , wheel. Quote Link to comment Share on other sites More sharing options...
bluedotsnow Posted March 27, 2012 Author Share Posted March 27, 2012 yes tried unplugging the TCU but I only drove the car I did not have time to put it on jack stands. I did not feel any binding what so ever. if a diff like mine (4eat) was not being powered but just rotating along with the road could there be an underlying problem that is not detectable without torque being applied through its drive shaft? Quote Link to comment Share on other sites More sharing options...
987687 Posted March 27, 2012 Share Posted March 27, 2012 It's almost impossible the diff broke in such a way that it won't transmit power to the wheels, and also didn't/doesn't make any really terrible awful noises. And even with the 4eat (working properly) there's still some torque going to the rear diff. When mine was failing it would make noise when under load (either accel or decel). But if I put in the FWD fuse it went away because it was just freewheeling. It would make noise just cruising down the highway at 65. So it's mostly fwd just cruising along. Quote Link to comment Share on other sites More sharing options...
johnceggleston Posted March 27, 2012 Share Posted March 27, 2012 if a diff like mine (4eat) was not being powered but just rotating along with the road could there be an underlying problem that is not detectable without torque being applied through its drive shaft? never heard of one. i have been driving a 95 AWD with no rear drive shaft for 40k miles, with no problems. Quote Link to comment Share on other sites More sharing options...
bluedotsnow Posted March 27, 2012 Author Share Posted March 27, 2012 you must not drive in the snow much?!? Quote Link to comment Share on other sites More sharing options...
johnceggleston Posted March 27, 2012 Share Posted March 27, 2012 i have been driving subarus here in VA for over 17 years and only one year have i really gotten to play in the snow. and that was in my 97 OBW. the 95 is really a college kid car, soon to be sold. Quote Link to comment Share on other sites More sharing options...
ivans imports Posted March 27, 2012 Share Posted March 27, 2012 Over 2000 subarus fixed one bad diff very rare to go bad only if low on oil or abused Quote Link to comment Share on other sites More sharing options...
bluedotsnow Posted March 27, 2012 Author Share Posted March 27, 2012 lol like I said in my other thread about no awd I just bought the car.... the diff oil that's in it was spotless with some shavings but who's to know what happened 100k prior did someone abuse this car? I paid what I though was a reliable source to check the car out before I bought it and he kinda let me down. I'm learning and plan on doing it myself from here on out. Quote Link to comment Share on other sites More sharing options...
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