440man Posted December 14, 2004 Share Posted December 14, 2004 I will be putting a 390 R200 out of an 81 ZX in my 75 280. Does anyone know if the flange coming off the differential to the driveshaft on the 81 can be removed and replaced with the stock 354 geared R200 flange from the 75 280 in order to use the stock 280 driveshaft, OR do I have to use a different drive shaft? I think I recall someone saying that this conversion requires a 1976-78 driveshaft, although it appears that the flanges could just be swapped out. Any thoughts? Thanks 440MAN 75 280Z - In Process "from the ground up" Quote Link to comment Share on other sites More sharing options...
JMortensen Posted December 14, 2004 Share Posted December 14, 2004 The flanges are the same until you get to the 300ZX R200s. What you have should bolt right up. Quote Link to comment Share on other sites More sharing options...
fl327 Posted December 14, 2004 Share Posted December 14, 2004 IF you have the stock 75 driveshaft, you will need the 76-8 driveshaft to use the 3.9 diff, or change flanges. problem is, 75-8 driveshafts are not rebuildable easily, so you pretty have to change the driveshaft. The stock 75 driveshaft flange is bigger and uses bigger bolts, and is the same flange as a 81-83 turbo diff flange. When I put my z31 LSD in, I had to change the flange to the more common type and use a 76-8 driveshaft, actually they are the same from 70-74, and 76-8. I picked up a spare driveshaft from a 72 and will put good ujoints in it for when I blow this one up from clutch kicking my car sideways. Quote Link to comment Share on other sites More sharing options...
datsunlover Posted December 14, 2004 Share Posted December 14, 2004 Oh crap.. so this means my 75 driveshaft will NOT bolt up to the 81zx r200 I have?!? crap crap crap.... Quote Link to comment Share on other sites More sharing options...
fl327 Posted December 15, 2004 Share Posted December 15, 2004 you should look and compare flanges before you do the hard stuff. if your car has the original diff and driveshaft, NO. Quote Link to comment Share on other sites More sharing options...
Doug71zt Posted December 15, 2004 Share Posted December 15, 2004 Matt - Just swap over your old diff flange to the new diff. You have an R200 in there right now, right? Doug Quote Link to comment Share on other sites More sharing options...
440man Posted December 15, 2004 Author Share Posted December 15, 2004 Hey Doug, So if I understand correctly, I should be able to remove the flange from the stock 3.54 R200 and install it on the 3.90 R200 and just use the stock 75 driveshaft. Right? Thanks Guys Quote Link to comment Share on other sites More sharing options...
440man Posted December 15, 2004 Author Share Posted December 15, 2004 By the way, the flanges aren't the same on all years up to 300's. Quote Link to comment Share on other sites More sharing options...
wheelman Posted December 15, 2004 Share Posted December 15, 2004 Datsunlover, If you need a non-75 driveshaft I have the original from my 73 240 I'll sell you cheap. I'm not sure about the condition of the u-joints right off hand as I'm at work but I can check them out tonight when I get home. I don't remember feeling any play in it when I removed it but I'll check anyway. PM me if you're interested. Wheelman Quote Link to comment Share on other sites More sharing options...
datsunlover Posted December 15, 2004 Share Posted December 15, 2004 uh.. yah, what 440 said... I have the exact same 'dilema' as him.. I have the original (1975) 3.54 R200 on the floor, and the '82 zx 3.90 ready to go in (just have to get off my arse and go to the garage... ) So... Doug; you're saying the flange will just bolt on? I didn't even think ther'd be an issue with the flanges, as I checked out both diffs side by side, and they apeared to be identical.. guess I'll have to look harder.. I'm assuming I'm gona have a bitch of a time getting that nut off right? ps; I didnt intend to 'post hijack' here, it just that I have an almost identical issue/question so I thought i'd jump in.. I figured any answers I got would be the same ones 440man was looking for anyway. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted December 15, 2004 Share Posted December 15, 2004 Well I guess I stand corrected. I started with a 70, added a 80 ZX rear end, and it bolted right on. Then I swapped to the Z31 Turbo R200, and I swapped the flanges. Then I got a 200SX diff, and it has the same flange as the 80 ZX, and both bolt right up to my 70. I guess 75 is an oddball from the sounds of it. The pinion flange is swappable, but they are usually red loctited and the torque is in the ~150 ft/lbs range, so you'll need an impact or maybe someone sitting in the car standing on the brakes to get the flange loose. Sometimes the flanges are rusted on the splines, the last one I pulled off required a small pulley puller. Red loctite it and torque the crap out of it. Manual says 137-159 ft lbs, in stages of 50 lbs, and spin the pinion in between torques. Quote Link to comment Share on other sites More sharing options...
fl327 Posted December 15, 2004 Share Posted December 15, 2004 What I did was swap everything out to the more common 70-3, and 76-8 driveshaft and flange combo. 75s uniqueness makes them a little harder to replace quickly, changing stuff out to the more common flanges gives me more choice in finding good used driveshafts, since you will have 7 years of interchangability vs. 1. Quote Link to comment Share on other sites More sharing options...
datsunlover Posted December 16, 2004 Share Posted December 16, 2004 The pinion flange is swappable' date=' but they are usually red loctited and the torque is in the ~150 ft/lbs range, so you'll need an impact or maybe someone sitting in the car standing on the brakes to get the flange loose. Sometimes the flanges are rusted on the splines, the last one I pulled off required a small pulley puller. Red loctite it and torque the crap out of it. Manual says 137-159 ft lbs, in stages of 50 lbs, and spin the pinion in between torques.[/quote'] Hmm.. well, both diffs are currently sitting on the floor in my garage.. I don't have an air compressor or any air tools though. I guess I could bring it to work..although my boss's impact gun kinda sucks.. and I don't know how I'd hold the thing steady so the driveshafts wont fly around! I'll see if I can get the old one off first.. evrything I pulled off the 280zx parts car came off pretty good... (7 years newer, about 100 LESS k's on it than my 75!) so if I can get the old flange off, I'm sure I'll be able to swap them.. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted December 16, 2004 Share Posted December 16, 2004 Just wrap the yoke with a rag and hold onto it with your hand. Quote Link to comment Share on other sites More sharing options...
Doug71zt Posted December 16, 2004 Share Posted December 16, 2004 The pinion shaft splines are all the same on long nose R200, so just take the flange you need to match you driveshaft and slap it on the diff. It is a good idea to keep the other flanges around, because they can be handy down the road. It will likely require an impact and a gear puller to get it off if its an Ontario car... Good luck Doug Quote Link to comment Share on other sites More sharing options...
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