Gyoas759 Posted March 30, 2008 Share Posted March 30, 2008 I was reading up on on of the Datsun boards on the LSDs and the 510 swaps. According to on author there, the older Subaru LSDs weren't always and actuall differential, but merely had lower gearing. I poked around and looked at all my stickers. Both my 83s have a 3.900, the 84 turbo has a 3.700 and the 82 has no sticker at all. Originally I thought the sticker just fell off the 82, but after reading the datsun stuff, I'm wondering what it really is. Anyone care to give a rundown on these things? Link to comment Share on other sites More sharing options...
Turbone Posted March 30, 2008 Share Posted March 30, 2008 For what I've gathered the M/T's are 3.9, unless they are from a fulltime box. Then they are 3.7. Most, if not all, of the AT's are 3.7. This is for EA's and ER's. I'm not up on the EJ's...yet. Link to comment Share on other sites More sharing options...
Gyoas759 Posted March 30, 2008 Author Share Posted March 30, 2008 That's been my observation in general. Of course one of my 83s with the 3.9 is an auto, but who know's what it's whole story is. My largest question is about this LSD that isn't really an LSD is all about. I'll let the Datsun guys' words explain. here are a few excerpts from the writeup I read. "The hard part about finding these LSD units is that almost any Subaru could be ordered with one, yet very few actually were. I'd guess that less than 5% of the cars came with LSD units, judging by what I've seen in yards. Perhaps those of you in mountainous/snowy climes might see more LSDs than those of us in flat/hot areas. What this means that there is no "one" Subaru that for sure has an LSD unit of a given ratio. Most likely clutch-pack LSD candidates are the '85-89 EA82 platform 4WD turbo cars, often with the 4AT (4 spd Auto) tranny." "A major problem is that most yard folks don't know much about them, and don't know how to tell an LSD from an non-LSD unit. Furthermore, I've heard from several yards that there are different universal listing code numbers for an open and a locked Subaru R-160 differential, but that there is just a single code for all 3.90 ratio Subaru differentials, making it impossible for them to search via teletype for 3.90 LSDs. Many people I know have been sold LSDs that actually weren't, so make sure it's an actual LSD before you pay for it or at least know what the return policy is before you leave the yard." "Subaru made it easier for us to tell what kind of differential is installed in their cars by just looking under them. Almost all of the older Subaru differentials (both LSD and Non-LSD) have a gold or silver foil sticker on the outside of the rear case cover stating the Subaru differential part number, the ratio of the differential (i.e. 3.70, 3.90, 4.11) and whether or not it is an LSD" What's up with that? And given that I may be putting a 4 speed D/R into my 83 with the 3.9, is that going to be a problem? Can the tranny have different gearing than the LSD? Link to comment Share on other sites More sharing options...
Turbone Posted March 30, 2008 Share Posted March 30, 2008 Pretty much everything said is true, with the exception of the 4EAT having most of the LSD's. You would need to put the LSD innards into your 3.9 case for it to work. You do not want to run different ratios on the tranny and rear diff. Theres a write up in the USRM for the swap. Link to comment Share on other sites More sharing options...
joostvdw Posted March 30, 2008 Share Posted March 30, 2008 The thing they didnt' mention is how to check if it's an LSD Just turn one of the wheels/axle stubs and see which way the other rotates Same direction? LSD Opposite direction? non-LSD It's THAT easy :-p Link to comment Share on other sites More sharing options...
Gyoas759 Posted March 30, 2008 Author Share Posted March 30, 2008 The thing they didnt' mention is how to check if it's an LSD Just turn one of the wheels/axle stubs and see which way the other rotates Same direction? LSD Opposite direction? non-LSD It's THAT easy :-p Gotcha. The one that's unmarked turns opposite. So what shall I call it? It's just a differential I guess? Link to comment Share on other sites More sharing options...
Turbone Posted March 30, 2008 Share Posted March 30, 2008 Its called a open diff Link to comment Share on other sites More sharing options...
Gyoas759 Posted March 30, 2008 Author Share Posted March 30, 2008 Its called a open diff Thanks! I read up on the LSD swap. Doesn't look too hard, but I'm still a little unclear on the relationship between the tranny and LSD. The write ups concern swapping your diff from a 3.7 to 3.9 but the tranny isn't mentioned. I ask because I have an 83 Wagon with a bad automatic tranny. It has a 3.900 LSD on it and I'm hoping to swap a D/R 4 speed in it. I'm guessing, but not sure yet that the tranny I have, which came from my 82 parts car had the 3.7 open diff. The extra auto tranny I have from my 84 turbo had a 3.7 LSD. Does this mean that to swap one of my other trannies into the 83 that I need to swap the LSD to a 3.7? Link to comment Share on other sites More sharing options...
Turbone Posted March 30, 2008 Share Posted March 30, 2008 The 4spd D/R is going to be a 3.9, so if you take a LSD(which almost all are 3.7) and convert it to 3.9 you will be good to go. The setup you have right now, the AT is a 3.7 and with a 3.9 rear diff is wrong and probably why you are having problems. Link to comment Share on other sites More sharing options...
Gloyale Posted March 30, 2008 Share Posted March 30, 2008 Thanks! I read up on the LSD swap. Doesn't look too hard, but I'm still a little unclear on the relationship between the tranny and LSD. The write ups concern swapping your diff from a 3.7 to 3.9 but the tranny isn't mentioned. I ask because I have an 83 Wagon with a bad automatic tranny. It has a 3.900 LSD on it and I'm hoping to swap a D/R 4 speed in it. I'm guessing, but not sure yet that the tranny I have, which came from my 82 parts car had the 3.7 open diff. The extra auto tranny I have from my 84 turbo had a 3.7 LSD. Does this mean that to swap one of my other trannies into the 83 that I need to swap the LSD to a 3.7? You talk about it as if you think the LSD diff is in the Tranmission. It's not. There is a differential in the front of the trans, but none of them are LSD. I don't think you understand that the LSD differentials we are talking about are rear diffs. The rear diff ratio must match the front diff in the transmission(which none are LSD) Other than that, they are totally separate and independent items You also contradict yourself. you say your 84 Turbo has 3.7 LSD, but then you ask if you will need to swap it to 3.7? Personally, I doubt any of those vehicles have Limited Slip. As far as I know, it was not offered even as an option until 1985 with the introduction of the EA82. MAYBE the 84 Turbo would have it. But you're 83, 3.9 automatic??? And an 82?? No way. Until you understand: A) what a differential is and does What a Limited slip differential is and does C) the fact that Subarus have a front and rear differential, and only the rear diffs were available in Limited Slip (LSD) D) That adding an LSD won't give you any more power or gearing than an open diff of the same ratio. .........you should hold back your Questions. I think if you search and learn about this stuff, you will answer your own questions. Link to comment Share on other sites More sharing options...
Gyoas759 Posted March 30, 2008 Author Share Posted March 30, 2008 You talk about it as if you think the LSD diff is in the Tranmission. It's not. There is a differential in the front of the trans, but none of them are LSD. I don't think you understand that the LSD differentials we are talking about are rear diffs. The rear diff ratio must match the front diff in the transmission(which none are LSD) Other than that, they are totally separate and independent items You also contradict yourself. you say your 84 Turbo has 3.7 LSD, but then you ask if you will need to swap it to 3.7? Personally, I doubt any of those vehicles have Limited Slip. As far as I know, it was not offered even as an option until 1985 with the introduction of the EA82. MAYBE the 84 Turbo would have it. But you're 83, 3.9 automatic??? And an 82?? No way. Until you understand: A) what a differential is and does What a Limited slip differential is and does C) the fact that Subarus have a front and rear differential, and only the rear diffs were available in Limited Slip (LSD) D) That adding an LSD won't give you any more power or gearing than an open diff of the same ratio. .........you should hold back your Questions. I think if you search and learn about this stuff, you will answer your own questions. I'm aware of the seperation. I have the rear diff off my 82 sitting on my porch right now. As for the contradiction, we're talking about 3 different cars here. 1. An 83 gl with a 3.9 diff and automatic trans 2. an 82 GL with a, previously thought 3.7 but now I know it's 3.9, diff and 4 speed D/R, and 3. an 84 Turbo wagon with a 3.7 and automatic. The 83 is the car the car in question for the swap. The 82 was parted and the 84 is being parted. Either was a cantidate to donate a transmission. My question was one of compatability. Until Turbone answered my question with the fact that the D/R was a 3.9 ratio, I was under the impression that I probably had a 3.7 transmission going into a car with a 3.9 Diff. As for LSD, my mistake. I'm not really concerned with Limited slip vs. open right now. I had also just assumed that it was limited slip. I've since checked and you're correct that the LSDs are all open diff. My questions are only pertaining to compatability. The tranny in the 83 is about dead and I'm hoping to throw the D/R in it. I did some searching on LSDs (Assuming it's what I had at the time) and didn't get my answer. So I asked a question and here we are. It's how I learn and I appreciate the help I've gotten from Turbone on this topic and many others in the past. (Yourself included.) Sorry for my ignorance on the topic, but I'm not trying to impress anyone. Just figuring out how to get the job done and make sure I'm not making any huge mistakes along the way. I know what I need to know now about diffs to go ahead with my swap. The D/R 4x4 will go right in, the auto would require I swap the 3.7 in as well. LSDs can wait for another day. Link to comment Share on other sites More sharing options...
Gyoas759 Posted March 30, 2008 Author Share Posted March 30, 2008 LSDs are all open diff? Huh? Oops. Let me rephrase. "My EA81 Differentials are all open differentials." Now I really sound dumb. But again. Until an hour ago I was under the impression that they were all limited slip. Link to comment Share on other sites More sharing options...
Gloyale Posted March 30, 2008 Share Posted March 30, 2008 The 83 is the car the car in question for the swap. The 82 was parted and the 84 is being parted. Either was a cantidate to donate a transmission. My question was one of compatability. Until Turbone answered my question with the fact that the D/R was a 3.9 ratio, I was under the impression that I probably had a 3.7 transmission going into a car with a 3.9 Diff. Cool. It sound like you figured it out. You just have to match your transmission and rear diffs. LSD vs. OPEN is a seperate thing, but then still dependant on a matching diff and trans. Hope my comments weren't taken with offense. Now that you've clarified about the supposed LSDs(which turned out were actually jut open diffs) this thread makes a whole lot more sense. You basically had a gearing question. Adding the LSD swap talk just made it all very confusing. Link to comment Share on other sites More sharing options...
Gloyale Posted March 30, 2008 Share Posted March 30, 2008 But again. Until an hour ago I was under the impression that they were all limited slip. I think we just want them all to be Limited Slip:rolleyes: "People, please, Can't we all just get a lock??" Link to comment Share on other sites More sharing options...
Gyoas759 Posted March 30, 2008 Author Share Posted March 30, 2008 Nah, no offense taken. Now that I know there's both open and limited slip, as well as swaps to go from open to limited, and that EA81s didn't have limited I see how I came across. But I think I'm all set now as far as differentials are concerned. Now I just need to get into the nuts and bolts of going from an auto to 4 speed D/R. (Crosses fingers) Link to comment Share on other sites More sharing options...
Turbone Posted March 30, 2008 Share Posted March 30, 2008 You have more reading to do :-p http://www.ultimatesubaru.org/forum/showthread.php?t=67990&highlight=auto+to+manual+swap Link to comment Share on other sites More sharing options...
MilesFox Posted March 30, 2008 Share Posted March 30, 2008 here is what i know n'a cars are 3.9 turbo cars are 3.7 the xt6 full time had vlsd 3.9 on some of them the rx had lsd from the factory 85 and 86 and maybe some 87 ea82 3at non turbos had 3.7 diffs. Link to comment Share on other sites More sharing options...
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