aartod Posted October 20, 2007 Share Posted October 20, 2007 How difficult is it to replace the two seals in the trans that go to the front cv shafts? I am replacing my front cv shafts today and noticed that one of my trans seals may be leaking -- although it is hard to tell, due to the fact that my cv joint spewed grease all over the place! Is this a difficult task and how do I go about replacing them? Any suggestions? Quote Link to comment Share on other sites More sharing options...
idosubaru Posted October 20, 2007 Share Posted October 20, 2007 first, check your fluid level to see if you're loosing it. if it's leaking your fluid level has to decrease. it's not terribly difficult, but it is tricky and critical that it's done very precisely. i'm not an expert on the deal, but the retainer around that seal has to come out of the trans and those adjust some kind of pre-load on the bearings or front diff inside the trans. basically if you mark it and count how many revolutions to remove it and then install it with the same number of revolutions and back to it's original position yo'ure fine. not difficult, just be sure to get it exactly the same as it was before. but, i would assume it's just grease that's been heated and running in that area. definitely rule that out before assuming the worst. Quote Link to comment Share on other sites More sharing options...
tcspeer Posted October 21, 2007 Share Posted October 21, 2007 You will need seals and O-rings for that. I bought some for my legacy wagon and was going to change them but got scared off by the things Gary was telling you about, but it was from other people here and not him. So I ran mine untill torque bind set in and then changed the transmission with one from the wrecking yard. After I got the old transmission out, I then took the covers off and removed the seals and O-rings from where the axle stub went in, if I remember there is a little bolt you need to remove then spin the outer housing off, You will see the O ring and seal from here both are easy to get to and change. I did not see why this would affect anything internal as it looked to me like it just covered the hole and let the axle stub have a place to come out, my thoughts are, this is the front diff. and not the transmission and the gears in this unit are very large and I dont see this changing much, but I AM NOT a transmission person so wait for someone here to say for sure or ask at a transmission shop before doing it. How difficult is it to replace the two seals in the trans that go to the front cv shafts? I am replacing my front cv shafts today and noticed that one of my trans seals may be leaking -- although it is hard to tell, due to the fact that my cv joint spewed grease all over the place! Is this a difficult task and how do I go about replacing them? Any suggestions? Quote Link to comment Share on other sites More sharing options...
GeneralDisorder Posted October 21, 2007 Share Posted October 21, 2007 Those retainers do set the front diff preload and need to be marked as to their orientation and set back EXACTLY the same when doing those seals. Without splitting the case there is no way to properly set that preload so it's critical that you put them back exactly where you found them after doing the seals. If you don't you'll ruin the front diff. These change the orientation of the ring gear and pinion inside the front diff - it is critical that they mesh completely and properly or both will be destroyed in short order. Make sure you really need those seals and the grease button hasn't popped free from the inside of the DOJ cup. You could be seeing CV grease and not gear oil. At any rate those seals rarely fail. GD Quote Link to comment Share on other sites More sharing options...
tcspeer Posted October 21, 2007 Share Posted October 21, 2007 You may be right, it seems that is stated here quite often, could you please explain how this sets the preload, I did not see how this could be but I must admit you hold the more common belief here so I can not argue that point. Those retainers do set the front diff preload and need to be marked as to their orientation and set back EXACTLY the same when doing those seals. Without splitting the case there is no way to properly set that preload so it's critical that you put them back exactly where you found them after doing the seals. If you don't you'll ruin the front diff. These change the orientation of the ring gear and pinion inside the front diff - it is critical that they mesh completely and properly or both will be destroyed in short order. Make sure you really need those seals and the grease button hasn't popped free from the inside of the DOJ cup. You could be seeing CV grease and not gear oil. At any rate those seals rarely fail. GD Quote Link to comment Share on other sites More sharing options...
johnceggleston Posted October 21, 2007 Share Posted October 21, 2007 some one recently posted a FSM section on the 99? auto trans, i think. it went in to great detail about shimming the pinion gear in the diffential and setting the ring gear with the 2 retaining rings, one at each axle. reading the description of the procedure for putting it together correctly gave me a very good understanding of how it is supposed to work. in a nut shell, if my memory serves me correctly. the pinion and ring gear must mate correctly or they wear funny, badly. solutions were given for too-much-of-this or not-enough-of-that. but what i remember about the retaining rings and the differential is this: after you get the pinion right, you thread in the retaining rings until each one just touches and then back it off. you do this several times to make sure you do not go too far. then, you thread one side IN and the other side OUT the EXACT same (pre set ) number of turns (1.75 turns?). this shifts the ring gear, etc., in the correct direction the correct distance. ( i didn't even bother to try and remember the amount or the direction since i didn't think i'd need it and i knew i would never be able to remember it if i did need it. if i do, i'll do a search.) the long and the short of it is, if you replace the seals ONE SIDE AT A TIME and you re-thread IN the EXACT same number of turns you threaded OUT, you should be able to replace the seals without damaging the differential. but, i'm still in the how-much-is-it-really-leaking camp. if it's not making you add gear oil every few months, why bother. try this at your own risk. gear oil is cheap. Quote Link to comment Share on other sites More sharing options...
GeneralDisorder Posted October 21, 2007 Share Posted October 21, 2007 Here's a section from an 84 FSM. The procedure is similar for all Subaru manual transaxles - this just happens to be what I have on hand at the moment. It's NOT something you want to have to do unless you are rebuilding the transmission on a bench. Here's the link to a larger version if you actually want to read it : http://home.comcast.net/~trilinear/preload_big.jpg GD Quote Link to comment Share on other sites More sharing options...
tcspeer Posted October 21, 2007 Share Posted October 21, 2007 John & Gen. those are two very good posts, I have heard this here but never did understand, (in fact still dont) but I know enough about it now that I wont change them even through it's looks like a very easy job. Thanks for the insight. Quote Link to comment Share on other sites More sharing options...
cookie Posted October 21, 2007 Share Posted October 21, 2007 It's miserable enough to set preload on a regualr rear end. You used to have to use grease or mechanic's blue to see the contact patch. Adjust ability is good becuse otherwise you have to use shims. Never done it on a Subaru and don't want to. If you set it back exactly where you go it it will be fine, but otherwise you can run into gear whine or worst case running on the gear edge and haveing it break, very expensive error. Quote Link to comment Share on other sites More sharing options...
tcspeer Posted October 21, 2007 Share Posted October 21, 2007 Cookie, if I remember right I think it was you that first told me of the dangers of changing them seals, It's a good thing I listened or I might have had to change that transmission a couple of years earlier. It's miserable enough to set preload on a regualr rear end. You used to have to use grease or mechanic's blue to see the contact patch. Adjust ability is good becuse otherwise you have to use shims. Never done it on a Subaru and don't want to. If you set it back exactly where you go it it will be fine, but otherwise you can run into gear whine or worst case running on the gear edge and haveing it break, very expensive error. Quote Link to comment Share on other sites More sharing options...
aartod Posted October 21, 2007 Author Share Posted October 21, 2007 Thanks for all the info! I think that I will assume it is grease and not gear oil-- it does not have that gear oil smell-- and if those seals are leaking then I will fix it later... subaru cv shafts are very easy to remove! Thanks Quote Link to comment Share on other sites More sharing options...
idosubaru Posted October 21, 2007 Share Posted October 21, 2007 but otherwise you can run into gear whine. yep, i know someone that did a bad install, ruined the new front diff. Quote Link to comment Share on other sites More sharing options...
cookie Posted October 22, 2007 Share Posted October 22, 2007 We may be old TC but we ain't stupid yet. Quote Link to comment Share on other sites More sharing options...
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