Rittmeister
09-01-2006, 11:49 PM
For the new 240SX Tech section.
First, the original install thread(s) are here: http://www.sr20forum.com/showthread.php?t=123599
http://www.sr20forum.com/showthread.php?t=124548
They have most of the details, but this will be step-by-step. I will also cut and paste the abbreviated install thread below here, to include the pictures and some other specifics. This how-to should work for both S13 and S14 cars, with open or viscous differentials.
Tools: 17mm, 14mm, 12mm, sockets and wrenches, torque wrench, and breaker bars. Rubber mallet/deadblow hammer. Pry bar. BIG bench vise.
It's also helpful to have the S13 and S15 FSMs on hand; you can download them from www.zeroyon.com
Parts: S15 HLSD (duh); S15 output shafts; new bearings and races if you've got 'em. Mine came all together and I encourage you to have all new parts. If you're doing a VLSD install into your open-diff casing, you'll need VLSD outputs; most aftermarket clutch-type diffs also require VLSD outputs, but make sure you get what's appropriate. NOTE: if you're installing a different-ratio ring and pinion, you're on your own. You can't just install a ring gear and have it work with the stock pinion, and I understand that installing the pinion is really an adventure.
I also got a new rear-cover gasket. You may be able to re-use the old one but why take a chance? They're cheap.
Finally you'll need 80w90 gear oil, 1.5 quarts. I used Valvoline synthetic blend, recommended for both S13 and S15 diffs.
Pre-work note: the diff casing is one heavy SOB. Be careful, get help if you need it, and DON'T drop it on your foot.
1. Jack the back of the car up and secure it with jackstands, and chock the front wheels. Drain the fluid from the differential casing - one 1/2" drive square plug, like the tranny. It's much easier to do this while it's on the car.
2. Remove pumpkin from the car. On an S13, that's two 17mm bolts at the front of the carrier, four nuts at the rear, four 14mm bolts on the driveshaft, and six 12mm bolts on each axle. On an S14, it's all the same except that instead of having four nuts on the back, there are two.
Tips:
-You can let the driveshaft hang, there's no reason to take it out of the car.
-You can wrestle the axles away from the output shafts without removing the axles themselves, or for that matter without taking the wheels off if you don't want to.
-Depending what exhaust you have you may need to remove the rear section. I have done this on my car, with a Veilside 3" exhaust, and on a car with a stock exhaust, and neither needed to be removed.
-Some will say you must remove the swaybar; at least on an S13 that's crap, leave it on.
3. Get the diff casing up onto a bench where you can work.
4. Remove rear cover - 8 14mm bolts. I used an electric impact gun on these, made it go nice and quick.
5. Remove output shafts. A combination of prying and tapping with the mallet and these pop right out - easier than an axle on a FWD SR tranny :D Take care not to damage the side oil seals.
6. Remove the four bearing cap bolts (17mm) and set the bearings caps aside. DON'T mix them up. At this point, in SCC's words, the diff should fall out, but when it doesn't, use the prybar; just don't mar the ring gear.
7. When the diff falls out, the bearing races and spacers will also. You MUST keep them in the same order when you re-install the new diff, or the ring-gear spacing could be drastically wrong.
8. Now the difficult part. You must transfer the ring gear from the S13 open-diff onto the S15 helical diff. It's held on by 10 incredibly tight bolts. The open diff will fit into most bench vises; air tools, electric impact (what I used) big breaker bar, pipe, whatever, you'll need it, those suckers are ON there.
9. Once you have the ring gear off, move the open diff away (sell it to some sucker who wants a welded diff) and put the S15 diff in the vise. It's bigger than the open diff, and will not fit in some smaller vises.
Tip - at this point you have a decision to make. The S13 ring gear and ring gear bolts will obviously work together; however the ring gear bolt holes in the S15 diff are larger than the bolts. Checking both FSMs shows that the S15 bolts are bigger, with a higher torque spec than the S13 bolts. I fashioned spacers to go around the bolts to fill the holes, out of some aluminum sheet I had in the garage. More recently someone on Freshalloy found that you could use a particular bushing, here's the thread: http://forums2.freshalloy.com/showthread.php?t=154986&highlight=hlsd If I were doing this now, I'd use the bushing. There are folks who have used nothing, and had no problem.
10. Work the ring gear onto the HLSD and get two bolts into it, opposite each other, to hold it steady.
11. Put Loc-Tite (I used blue, red would work too) on each bolt and thread them in fully. Then you must do a final tightening in a criss-cross pattern, similar to tightening lug nuts, to maintain even torque around the ring gear. The torque spec for the S13 is 112 ft-lb; you MUST use this number.
12. Now the diff must go back into the casing. It only goes one way, no problem there. Put the bearing races back over the bearings (lube them a bit if you want) and wedge them into the case. It's best to have help here; two hands are only barely enough. Put the shims back in, in the same order they came out. Leave the thinnest for last, wherever it goes; you'll most likely have to tap it in with the mallet, it's designed to be a tight fit. Re-install the bearing caps on the sides they came off of, and torque to spec.
-Tip: here, the FSM makes a lot of noise about backlash and spacing; I didn't know how to check this and didn't check it, and there's been no problem. Before installing it onto the car I had my mechanic check it out (by feel and sound and sight) and he pronounced it healthy. SCC, NekoPunch, and others have done it this way with no issues; whether you do is up to you, but either way if you blow up your car it's your problem, NOT mine.
13. Re-install the rear cover with a new gasket, and tap the new outputs into place - they simply slide in with a little help from the mallet. I also installed new side-oil-seals, which go in in much the same manner that the front/rear main seal or FWD axle seals do.
14. Fill 'er up with fluid. You MUST do this when it's off the car, you can't get to the fill port when the casing is re-installed.
15. Now you must wrestle the pumpkin back onto the car. Having help is good but not necessary. I set it on a jack, got the nose up over the swaybar, and jacked it up while keeping the left side pointed upwards to clear the exhaust. Once it's high enough, get the four studs on the rear through the holes in the subframe and get a few nuts on them; raise the front the rest of the way and bolt it up. Tighten everything down, re-attach the axles and driveshaft.
16. Enjoy the ride. Two wheel drive is pretty sweet.
Below is the original, abbreviated install thread with pics. I edited it a bit to make it more understandable (I hope).
Diff:
http://www.sr20forum.com/img/data/500/medium/p7220061.JPG
Diff w/ring gear:
http://www.sr20forum.com/img/data/500/medium/P7220059.JPG
Bearing races:
http://www.sr20forum.com/img/data/500/medium/P7220060.JPG
I spent the early afternoon today installing the new diff into my stock open-diff carrier. Things seemed to go just fine.
Pertinent info:
1. I bought my diff with the outputs from ebay. The seller (seller id is mx83*gx81) had very large positive feedback and had sold a number of these setups recently. As far as I can tell, both from appearance and packaging, the outputs are brand new. I don't know about the diff; it had NO grease/oil/dirt of any kind on or in it, and in any case it appears to be in extremely good condition if it is used.
NB: if you get a diff with no outputs, www.jspec.com has them for a little over $300 for the pair.
2. You must install the ring gear from your open diff onto the S15 diff, unless you're going with a different final drive, in which case you'll need to install the new ring AND the pinion/shaft into the casing.
The ring gear bolt holes in the S15 diff are a bit larger than those in the S13 open diff. I doubt very much that this would cause trouble (the bolts are supposed to be torqued to a max of 112 ft lb), if the gear shifted at all it would just bump up against all 10 bolts and stop moving. I went the extra mile and fashioned some spacers out of sheet metal I had around the garage and I anticipate no problems.
NB: use loctite on ring gear bolts and bearing cap bolts!
NB: I checked both the S13 and S15 FSM for this install. The ring gear bolt torque specs are different for the two. USE THE S13 TORQUE NUMBERS! The S15 ring gear bolts are larger and therefore have a higher torque spec. You probably wouldn't break your bolts with the extra twist but BOY would you feel stupid if you did.
3. When I removed the open diff from the casing I laid everything out very carefully on the workbench so I could reinstall it in the same order. This is akin to the way we all lay out cam bearing caps when doing a cam swap; you just want each piece to go back where it came from.
Parts laid out:
http://www.sr20forum.com/gallery/data/608/medium/P7220057.JPG
Left to right on my diff was: large spacer - small spacer - diff bearing race - differential - diff bearing race - small spacer.
When installing the diff/ring gear into the casing, it's impossible to get it oriented wrong, as you can see from the pic of the pinion below. It's offset from the center of the casing and I doubt the diff would even go in backwards.
4. The diff came with bearings already pressed onto it; if you get one and it doesn't, I have no idea what to tell you to get. It stands to reason with Nissan's part-sharing fetish that they'd be the same as S13/S14 bearings but I can't tell you for certain.
It was also provided with brand-new bearing races (the metal rings to the right of the diff in the first pic). These just fit over the bearings and in turn fit into the casing properly.
Left-to-right: output flanges (left is longer than right, or at least I'm assuming it is since that's the way the open diff outputs were), diff with ring gear installed, bearing races. Newly painted casing in the background.
http://www.sr20forum.com/img/data/500/medium/P7240057.JPG
Empty casing with view of the pinion; you can see how it's offset from the center.
http://www.sr20forum.com/img/data/500/medium/p7240061.JPG
Diff in its new home. I lubed the bearings as per the FSM, and I've left the outputs uninstalled until my new side oil seals and rear gasket arrive from Courtesy.
http://www.sr20forum.com/img/data/500/medium/P7240063.JPG
Other notes: people ask why you need the output shafts from an S15. Well, similar to the way that VLSD and open-diff outputs are different, the S15 outputs are different as well. I was told that they are larger in diameter; I suppose that may be true but I can't tell with the naked eye. The two sets of outputs DO however have different spline counts. The S15 shafts fit into the diff easily, whereas the S13 will not go in (though in the interests of not damaging anything I didn't try that hard).
Also: if you get an S15 diff in the pumpkin, I've heard various rumors about fitment but no verification. Some say it will fit S14 but not S13, some say it will fit neither because the mounting points are different. I say just get it the way I did without the casing, I've never seen a full S15 pumpkin for less than $800-$850 and then you have to ship the monster, and if you do it the way I did you know it'll fit into the car.
There's a lot of noise in the FSM about adjusting lash and runout of various items. For now, I've installed it the way the old diff was in there; if I turn the input shaft (where the driveshaft bolts on) by hand the diff turns with exactly the same effort and noise that the old diff did. If it acts wierd when I install it onto the car I'll go from there, but every install writeup I've ever seen (nekopunch, some on Zilvia and Freshalloy, SCC's Quaife) whether its an HLSD or clutch-type seems to have had no trouble.
I hope this answers some of your questions. I should have it installed onto the car later in the week; driving impressions will follow.
First, the original install thread(s) are here: http://www.sr20forum.com/showthread.php?t=123599
http://www.sr20forum.com/showthread.php?t=124548
They have most of the details, but this will be step-by-step. I will also cut and paste the abbreviated install thread below here, to include the pictures and some other specifics. This how-to should work for both S13 and S14 cars, with open or viscous differentials.
Tools: 17mm, 14mm, 12mm, sockets and wrenches, torque wrench, and breaker bars. Rubber mallet/deadblow hammer. Pry bar. BIG bench vise.
It's also helpful to have the S13 and S15 FSMs on hand; you can download them from www.zeroyon.com
Parts: S15 HLSD (duh); S15 output shafts; new bearings and races if you've got 'em. Mine came all together and I encourage you to have all new parts. If you're doing a VLSD install into your open-diff casing, you'll need VLSD outputs; most aftermarket clutch-type diffs also require VLSD outputs, but make sure you get what's appropriate. NOTE: if you're installing a different-ratio ring and pinion, you're on your own. You can't just install a ring gear and have it work with the stock pinion, and I understand that installing the pinion is really an adventure.
I also got a new rear-cover gasket. You may be able to re-use the old one but why take a chance? They're cheap.
Finally you'll need 80w90 gear oil, 1.5 quarts. I used Valvoline synthetic blend, recommended for both S13 and S15 diffs.
Pre-work note: the diff casing is one heavy SOB. Be careful, get help if you need it, and DON'T drop it on your foot.
1. Jack the back of the car up and secure it with jackstands, and chock the front wheels. Drain the fluid from the differential casing - one 1/2" drive square plug, like the tranny. It's much easier to do this while it's on the car.
2. Remove pumpkin from the car. On an S13, that's two 17mm bolts at the front of the carrier, four nuts at the rear, four 14mm bolts on the driveshaft, and six 12mm bolts on each axle. On an S14, it's all the same except that instead of having four nuts on the back, there are two.
Tips:
-You can let the driveshaft hang, there's no reason to take it out of the car.
-You can wrestle the axles away from the output shafts without removing the axles themselves, or for that matter without taking the wheels off if you don't want to.
-Depending what exhaust you have you may need to remove the rear section. I have done this on my car, with a Veilside 3" exhaust, and on a car with a stock exhaust, and neither needed to be removed.
-Some will say you must remove the swaybar; at least on an S13 that's crap, leave it on.
3. Get the diff casing up onto a bench where you can work.
4. Remove rear cover - 8 14mm bolts. I used an electric impact gun on these, made it go nice and quick.
5. Remove output shafts. A combination of prying and tapping with the mallet and these pop right out - easier than an axle on a FWD SR tranny :D Take care not to damage the side oil seals.
6. Remove the four bearing cap bolts (17mm) and set the bearings caps aside. DON'T mix them up. At this point, in SCC's words, the diff should fall out, but when it doesn't, use the prybar; just don't mar the ring gear.
7. When the diff falls out, the bearing races and spacers will also. You MUST keep them in the same order when you re-install the new diff, or the ring-gear spacing could be drastically wrong.
8. Now the difficult part. You must transfer the ring gear from the S13 open-diff onto the S15 helical diff. It's held on by 10 incredibly tight bolts. The open diff will fit into most bench vises; air tools, electric impact (what I used) big breaker bar, pipe, whatever, you'll need it, those suckers are ON there.
9. Once you have the ring gear off, move the open diff away (sell it to some sucker who wants a welded diff) and put the S15 diff in the vise. It's bigger than the open diff, and will not fit in some smaller vises.
Tip - at this point you have a decision to make. The S13 ring gear and ring gear bolts will obviously work together; however the ring gear bolt holes in the S15 diff are larger than the bolts. Checking both FSMs shows that the S15 bolts are bigger, with a higher torque spec than the S13 bolts. I fashioned spacers to go around the bolts to fill the holes, out of some aluminum sheet I had in the garage. More recently someone on Freshalloy found that you could use a particular bushing, here's the thread: http://forums2.freshalloy.com/showthread.php?t=154986&highlight=hlsd If I were doing this now, I'd use the bushing. There are folks who have used nothing, and had no problem.
10. Work the ring gear onto the HLSD and get two bolts into it, opposite each other, to hold it steady.
11. Put Loc-Tite (I used blue, red would work too) on each bolt and thread them in fully. Then you must do a final tightening in a criss-cross pattern, similar to tightening lug nuts, to maintain even torque around the ring gear. The torque spec for the S13 is 112 ft-lb; you MUST use this number.
12. Now the diff must go back into the casing. It only goes one way, no problem there. Put the bearing races back over the bearings (lube them a bit if you want) and wedge them into the case. It's best to have help here; two hands are only barely enough. Put the shims back in, in the same order they came out. Leave the thinnest for last, wherever it goes; you'll most likely have to tap it in with the mallet, it's designed to be a tight fit. Re-install the bearing caps on the sides they came off of, and torque to spec.
-Tip: here, the FSM makes a lot of noise about backlash and spacing; I didn't know how to check this and didn't check it, and there's been no problem. Before installing it onto the car I had my mechanic check it out (by feel and sound and sight) and he pronounced it healthy. SCC, NekoPunch, and others have done it this way with no issues; whether you do is up to you, but either way if you blow up your car it's your problem, NOT mine.
13. Re-install the rear cover with a new gasket, and tap the new outputs into place - they simply slide in with a little help from the mallet. I also installed new side-oil-seals, which go in in much the same manner that the front/rear main seal or FWD axle seals do.
14. Fill 'er up with fluid. You MUST do this when it's off the car, you can't get to the fill port when the casing is re-installed.
15. Now you must wrestle the pumpkin back onto the car. Having help is good but not necessary. I set it on a jack, got the nose up over the swaybar, and jacked it up while keeping the left side pointed upwards to clear the exhaust. Once it's high enough, get the four studs on the rear through the holes in the subframe and get a few nuts on them; raise the front the rest of the way and bolt it up. Tighten everything down, re-attach the axles and driveshaft.
16. Enjoy the ride. Two wheel drive is pretty sweet.
Below is the original, abbreviated install thread with pics. I edited it a bit to make it more understandable (I hope).
Diff:
http://www.sr20forum.com/img/data/500/medium/p7220061.JPG
Diff w/ring gear:
http://www.sr20forum.com/img/data/500/medium/P7220059.JPG
Bearing races:
http://www.sr20forum.com/img/data/500/medium/P7220060.JPG
I spent the early afternoon today installing the new diff into my stock open-diff carrier. Things seemed to go just fine.
Pertinent info:
1. I bought my diff with the outputs from ebay. The seller (seller id is mx83*gx81) had very large positive feedback and had sold a number of these setups recently. As far as I can tell, both from appearance and packaging, the outputs are brand new. I don't know about the diff; it had NO grease/oil/dirt of any kind on or in it, and in any case it appears to be in extremely good condition if it is used.
NB: if you get a diff with no outputs, www.jspec.com has them for a little over $300 for the pair.
2. You must install the ring gear from your open diff onto the S15 diff, unless you're going with a different final drive, in which case you'll need to install the new ring AND the pinion/shaft into the casing.
The ring gear bolt holes in the S15 diff are a bit larger than those in the S13 open diff. I doubt very much that this would cause trouble (the bolts are supposed to be torqued to a max of 112 ft lb), if the gear shifted at all it would just bump up against all 10 bolts and stop moving. I went the extra mile and fashioned some spacers out of sheet metal I had around the garage and I anticipate no problems.
NB: use loctite on ring gear bolts and bearing cap bolts!
NB: I checked both the S13 and S15 FSM for this install. The ring gear bolt torque specs are different for the two. USE THE S13 TORQUE NUMBERS! The S15 ring gear bolts are larger and therefore have a higher torque spec. You probably wouldn't break your bolts with the extra twist but BOY would you feel stupid if you did.
3. When I removed the open diff from the casing I laid everything out very carefully on the workbench so I could reinstall it in the same order. This is akin to the way we all lay out cam bearing caps when doing a cam swap; you just want each piece to go back where it came from.
Parts laid out:
http://www.sr20forum.com/gallery/data/608/medium/P7220057.JPG
Left to right on my diff was: large spacer - small spacer - diff bearing race - differential - diff bearing race - small spacer.
When installing the diff/ring gear into the casing, it's impossible to get it oriented wrong, as you can see from the pic of the pinion below. It's offset from the center of the casing and I doubt the diff would even go in backwards.
4. The diff came with bearings already pressed onto it; if you get one and it doesn't, I have no idea what to tell you to get. It stands to reason with Nissan's part-sharing fetish that they'd be the same as S13/S14 bearings but I can't tell you for certain.
It was also provided with brand-new bearing races (the metal rings to the right of the diff in the first pic). These just fit over the bearings and in turn fit into the casing properly.
Left-to-right: output flanges (left is longer than right, or at least I'm assuming it is since that's the way the open diff outputs were), diff with ring gear installed, bearing races. Newly painted casing in the background.
http://www.sr20forum.com/img/data/500/medium/P7240057.JPG
Empty casing with view of the pinion; you can see how it's offset from the center.
http://www.sr20forum.com/img/data/500/medium/p7240061.JPG
Diff in its new home. I lubed the bearings as per the FSM, and I've left the outputs uninstalled until my new side oil seals and rear gasket arrive from Courtesy.
http://www.sr20forum.com/img/data/500/medium/P7240063.JPG
Other notes: people ask why you need the output shafts from an S15. Well, similar to the way that VLSD and open-diff outputs are different, the S15 outputs are different as well. I was told that they are larger in diameter; I suppose that may be true but I can't tell with the naked eye. The two sets of outputs DO however have different spline counts. The S15 shafts fit into the diff easily, whereas the S13 will not go in (though in the interests of not damaging anything I didn't try that hard).
Also: if you get an S15 diff in the pumpkin, I've heard various rumors about fitment but no verification. Some say it will fit S14 but not S13, some say it will fit neither because the mounting points are different. I say just get it the way I did without the casing, I've never seen a full S15 pumpkin for less than $800-$850 and then you have to ship the monster, and if you do it the way I did you know it'll fit into the car.
There's a lot of noise in the FSM about adjusting lash and runout of various items. For now, I've installed it the way the old diff was in there; if I turn the input shaft (where the driveshaft bolts on) by hand the diff turns with exactly the same effort and noise that the old diff did. If it acts wierd when I install it onto the car I'll go from there, but every install writeup I've ever seen (nekopunch, some on Zilvia and Freshalloy, SCC's Quaife) whether its an HLSD or clutch-type seems to have had no trouble.
I hope this answers some of your questions. I should have it installed onto the car later in the week; driving impressions will follow.