Differential Help... 38311 P9000

[Patcon]

21 minutes ago, jl240z said:

I am looking at the OBX option as well.  Rich Bryant,( rich_bryant_is@yahoo.com), sells the upgrade kit for $34.  The unit had a lot of bad press and failures early on but the kit seems to fix it.  He has a web page that describes how to do it step by step.

http://rbryant.freeshell.org/obx_washers.htm

[z boy mn]

I don't know anything about the OBX LS options, but I can say that a year later I'm really pleased with my 4.11. I've had it on the track a few times and it really makes a huge difference even though most of it's life it's a daily driver. I did have an issue initially because the backlash on the pinion was WAY too tight (it calls for .0012-ish and mine was at .0001-ish). Once that got adjusted, I used Royal Purple diff fluid but the clutches were so tight it clunked still on hard corners. I called Royal Purple and they suggested adding more slip additive, and that did the trick.

While I'm happy with the result, I can see why the OBX could be a good option if it holds together. I think I had about $500 in parts (bearings, etc.) to overhaul the diff itself, and I had a new LSD to begin with from a 240SX from the PO. Those two bits added to the shop charge to adjust the backlash and it was an expensive option (luckily it took about a year so I didn't notice as much!). Good luck with your quest, and let us know how it turns out!

[jl240z]

13 hours ago, z boy mn said:

I don't know anything about the OBX LS options, but I can say that a year later I'm really pleased with my 4.11. I've had it on the track a few times and it really makes a huge difference even though most of it's life it's a daily driver. I did have an issue initially because the backlash on the pinion was WAY too tight (it calls for .0012-ish and mine was at .0001-ish). Once that got adjusted, I used Royal Purple diff fluid but the clutches were so tight it clunked still on hard corners. I called Royal Purple and they suggested adding more slip additive, and that did the trick.

While I'm happy with the result, I can see why the OBX could be a good option if it holds together. I think I had about $500 in parts (bearings, etc.) to overhaul the diff itself, and I had a new LSD to begin with from a 240SX from the PO. Those two bits added to the shop charge to adjust the backlash and it was an expensive option (luckily it took about a year so I didn't notice as much!). Good luck with your quest, and let us know how it turns out!

When I saw the date on the post I didn't know it my post would go thru.  I am new to the site.  I had joined ZCar.com almost about the time it was created back in the '70s, but if Im not logged in often enough it wont let me log back on and it takes awhile for the admistrators t get me back on.  So I found this site and decided to try it. I have had my "71 since I bought it brand new when I was stationed on Okinawa in the Air Force.  I have had it ever since and done different things with it.  It has been sitting for over 12 years and I finally decided to upgrade and use it again.  When you rebuilt your clutch type LSD, did you have to do anything special with the clutch pac's?  Or did you just replacer the old disks with new ones.. I probly should just use what I have for now.  The bearings all look good but I don't know how to judge the clutch disks. I know the gear type units are supposed to be better but I think they raced with this type back in the day and they were ok.  I am bleeding buks with all the stuff I want to do and using this diff may be what I should do for now.

[grannyknot]

21 hours ago, jl240z said:

I am looking at the OBX option as well.  Rich Bryant,( rich_bryant_is@yahoo.com), sells the upgrade kit for $34.  The unit had a lot of bad press and failures early on but the kit seems to fix it.  He has a web page that describes how to do it step by step. The price for the diff on ebay is $415-$479.  It sounds to good to be true but it may be worth a shot with the kit.  I have a R200 LSD clutch type as well, but it has a 4.67 in it.  I bought a 3.91 open diff so I could put the LSD into it.  I found a company in Japan, Negun Co. LTD, that sells part for it so i can replace all the clutch disc parts, but i cant get on the site.  Something about computer problems, theirs  or mine and i get kicked off it before i can inquire.   I did see one page that said the clutch disc set for one side was $27.  They had other kits that may have included bearings and seals, but i couldn't get on the site.  I think i hat ill write them and see if they will email me back so i can do it that way.  Anyway in case you didn't already know i am passing it on,  I may just order one of the diffs and a kit and see what happens.  Good luck

I did the same thing, $400 ebay OBX, Rich's fix kit and my R200 3.90 diff. I took it all apart, set it up as best as I could then took it up to my local transmission/diff shop to have them do the backlash properly.  I should have it back next week.  If you go this route you will need the clirclips that hold the stub axles in the diff, they don't come with the OBX unit. They are still available from Nissan, the PN is 38225-N3100,  they are part number #18, http://www.carpartsmanual.com/datsun/Z-1969-1978/power-train/differential-gear/r200

Chris

[Patcon]

Cool.

58 minutes ago, grannyknot said:

I should have it back next week

Post up you impressions here once it's in and you have some miles on it. Would be nice to add some feedback to the info already here

[jl240z]

Thanks I will save the part number.  I haven't looked at the stubs I have for a long time so I don't remember if they are on it or not.  I also will be interested on how it works out for you.  This is something I have wanted to do for a long time. I bought my car brand new in 1971 when I was stationed on Okinawa and have had it ever since. Its been parked for about 12+ years.  So its time to get busy. I bought the R200 LSD from Dave at Arizona Z car back when he was still getting them from Japan.  I never installed it because of the 4.67 gear and I only had the stock 4 speed.  So it has been sitting on my shelf for over 16 years.  I still have time to decide clutch type or OBX gear type.  The R200 long nose I  just got with the 3.91 gear may not have come out of a z car as it is about an inch longer and has a sensor of some type on the nose. I will just remove it as since I am putting in the T5 out of a turbo  I have to get a new drive shaft anyway.  This is a good opportunity to get an alum drive shaft. Either way I should be OK as I doubt that I will ever see a track.   But if life has ever taught me something its "never say never" Meanwhile I will be lurking and watching.  Later

[z boy mn]

I did not replace the clutch packs as the whole lsd unit was new. I did learn in my research process, though, that they weren't easily available so I'm not sure how I would have gone about replacing them if they had needed it. There's a local machine shop that could have made them, and that probably would have been my best option. It sounds like your lsd is new, too, or at least has very few miles on it. I don't think these parts go bad with time if they are stored properly.

As for cost--yeah, it's expensive and partly why I did mine over time.

Finally, this is a great site with all kinds of resources. I use it every time I do an upgrade of have an issue I can't figure out! Welcome to the group!

[jl240z]

Thanks, I am going to keep trying to contact the Negun Co. Ltd.  They may be a good source for other stuff besides LSD parts.  What would I give for a new LD28 crank that I could afford.  Some guy on ebay had a used one and wanted $2000 for it!!  They must be available somewhere in Japan.  They sell a lot of diesel stuff world wide and I heard it was a common engine in fork lifts and stuff like that.  The sad  tale is I had one for a long time and I sold it when I thot I would never redo my Z let alone build a stroker.  I think I paid less than $100 for it and didn't sell it for much more.   It was years ago but I am still kicking myself over that one.

[Gurmal]

I have an original 1982 280zx 2+2 the rear end out of it is 38311 N3100.  just for reference I see many posts on this number and wanted to give you all a reference of what year car it came out of.  My son is using the engine tranny and rearend for his 240z project.  I hope this helps google on a website and it said  280zx 81-83 (3.9) (r200)