yamahondarider Posted August 27, 2013 Share Posted August 27, 2013 Hey guys, I bought a 1976 280Z from a good friend of mine whos had it for as long as I've known him and finally sold it to me (for a good deal too!). Anyway, It runs and drives great but its only a 4 speed and a lot of the driving I do is 60+ MPH and I can really appreciate a 5th gear for highway use. He also has a 5 speed out of another z-car and I'm getting that from him. My question is, do I need another driveshaft, or is that the same between the two transmissions? Also, do I need a different clutch/pressure plate/flywheel or is that all the same between the two transmissions? I'll be ordering a new clutch either way, just want to know which to get. Can I pretty much just yank this tranny, and put the other in or do I need parts from a 5 speed z car? Thanks! Also, I'll get more specific info from him ASAP but as far as I know, its a 5 speed out of a 1975 280Z (thats the other car he had but stripped due to rust but I don't know for sure if its from that car or if he bought it already pulled from another car). Quote Link to comment Share on other sites More sharing options...
beermanpete Posted August 27, 2013 Share Posted August 27, 2013 The clutch and drive shaft are the same as long as the 5-speed is not a T5 from a Turbo. That caveat aside it is a straight bolt-in swap. Quote Link to comment Share on other sites More sharing options...
Tony D Posted August 27, 2013 Share Posted August 27, 2013 In the non-us market the 4 speeds came with a 3.70, and the 5 speeds came with a 3.90 Do some basic math and you realize the design speed is a lot higher than you think. I run the morning drive at 3200-3500 rpms with a 5 speed (early) and a 3.7 gearset in my L26, the same gearset in the L28 with a 3.90 seems to be just fine as well. 3,600 highway cruise is not bad... 2,500 is positively boring, and requires a two gear downshift to pass. Bleah! Quote Link to comment Share on other sites More sharing options...
NewZed Posted August 27, 2013 Share Posted August 27, 2013 1975 US cars didn't come with a 5 speed so you might spend a little time figuring out what you have. If it's a 77 Z - 83 ZX 5 speed, it will be a straight swap as beerman says. Check your rear main seal on the engine, and the front and rear seals on the transmission, they're easy to replace, pretty cheap, and you'll regret not doing it if you find they leak later. Also, on your 1976, if it's a Federal model, you'll lose the top-gear vacuum advance switch. It's described in the Emissions or Engine Fuel chapter in the FSM. Not a huge deal, but you might want to re-route the vacuum advance hose otherwise you'll never get vacuum advance of timing in the distributor. Quote Link to comment Share on other sites More sharing options...
yamahondarider Posted August 27, 2013 Author Share Posted August 27, 2013 In the non-us market the 4 speeds came with a 3.70, and the 5 speeds came with a 3.90 Do some basic math and you realize the design speed is a lot higher than you think. I run the morning drive at 3200-3500 rpms with a 5 speed (early) and a 3.7 gearset in my L26, the same gearset in the L28 with a 3.90 seems to be just fine as well. 3,600 highway cruise is not bad... 2,500 is positively boring, and requires a two gear downshift to pass. Bleah! Good to know, thanks for the info. So I shouldn't need to change my gearset or rear diff? 1975 US cars didn't come with a 5 speed so you might spend a little time figuring out what you have. If it's a 77 Z - 83 ZX 5 speed, it will be a straight swap as beerman says. Check your rear main seal on the engine, and the front and rear seals on the transmission, they're easy to replace, pretty cheap, and you'll regret not doing it if you find they leak later. Also, on your 1976, if it's a Federal model, you'll lose the top-gear vacuum advance switch. It's described in the Emissions or Engine Fuel chapter in the FSM. Not a huge deal, but you might want to re-route the vacuum advance hose otherwise you'll never get vacuum advance of timing in the distributor. Hmmm. How can I tell if my car is a Federal model? If need be do I just bypass that switch and run a straight vaccum line? The clutch and drive shaft are the same as long as the 5-speed is not a T5 from a Turbo. That caveat aside it is a straight bolt-in swap. Cool, I know its not out of a turbo car so it should be a bolt in. Sounds like it won't be more than a day long job. I don't have a transmission jack though, which seems like it'll make it a bit of a pain in the ass to swap. I have a floor jack and a motorcycle jack though, so I'll just get a bit creative. Quote Link to comment Share on other sites More sharing options...
Pharaohabq Posted August 27, 2013 Share Posted August 27, 2013 Your floor and motorcycle jack are plenty good enough to put the Tranny in, It only weighs about 80-100 lbs. I put one in by balancing it on my chest and pressing it up in place while my brother put a bolt in. Though When you're working on the car and getting under it, Please please use Jack stands. They're really cheap to buy, Harbor freight has them. $40 bucks is definitely worth not being crushed/killed or permanently disabled. Floor jacks have been known to fail w/o warning. Quote Link to comment Share on other sites More sharing options...
Phantom Posted August 27, 2013 Share Posted August 27, 2013 Your '76 should have a 3.54:1 R200 to go with the original 4-spd. The 5-spd sold with the '77 & '78 models have the same basic gearing as your 4-pd except for the 5th gear overdrive. In an ideal world you'd get the 5-spd and 3.90:1 R200 out of an '82 or '83 S130. The gear ratio combinations of the transmission and the differential will give you better initial acceleration and lower RPM's at highway spd. I did that with my '77 that came as a 4-spd car and was very satisfied. Quote Link to comment Share on other sites More sharing options...
yamahondarider Posted August 28, 2013 Author Share Posted August 28, 2013 Your floor and motorcycle jack are plenty good enough to put the Tranny in, It only weighs about 80-100 lbs. I put one in by balancing it on my chest and pressing it up in place while my brother put a bolt in. Though When you're working on the car and getting under it, Please please use Jack stands. They're really cheap to buy, Harbor freight has them. $40 bucks is definitely worth not being crushed/killed or permanently disabled. Floor jacks have been known to fail w/o warning. Good to know, I've manhandled a 1952 Dodge Coronet transmission around before so if thats all the Datsun's weighs I should be able to do this pretty easily I'm a strong guy. I do a lot of work on cars so I've got an assortment of jacks and jackstands and ramps and such, I have a fear of being crushed so I take that stuff very seriously. I wish I had a lift but I'm just glad I have a paved driveway. Working in gravel SUCKS Your '76 should have a 3.54:1 R200 to go with the original 4-spd. The 5-spd sold with the '77 & '78 models have the same basic gearing as your 4-pd except for the 5th gear overdrive. In an ideal world you'd get the 5-spd and 3.90:1 R200 out of an '82 or '83 S130. The gear ratio combinations of the transmission and the differential will give you better initial acceleration and lower RPM's at highway spd. I did that with my '77 that came as a 4-spd car and was very satisfied. So what would it be like to drive the car with the current rear end, and the 5 speed out of a 77-78? Would it be worth it to swap or should I put it on the back burner until I get a matching rear? The rear is making knocking sounds going over bumps and when you shift (suspension clunk) so eventually I have to dig into that anyway. It has all new bushings and such except the mustache bar bushing so I think thats where the problem lies. Quote Link to comment Share on other sites More sharing options...
Pharaohabq Posted August 28, 2013 Share Posted August 28, 2013 It would be more fun than driving it with the 4 speed You shouldn't have much trouble manhandling the S30 5 speed. it's really not that bad. it's not one hand lifting mind, you, but it's definitely lighter than a lot of them. Quote Link to comment Share on other sites More sharing options...
yamahondarider Posted August 28, 2013 Author Share Posted August 28, 2013 It would be more fun than driving it with the 4 speed You shouldn't have much trouble manhandling the S30 5 speed. it's really not that bad. it's not one hand lifting mind, you, but it's definitely lighter than a lot of them. I've got a friend of mine who'll give me a hand if I ask. I've helped him pull and install the motor in his VW Bug a few times so I'm sure he wouldn't mind helping me put a trans in the datsun. We'll see how it all goes, I'll put a build thread soon enough and the tranny swap will be part of it. I haven't bothered putting a build thread up yet because for the first time ever I literally haven't had to do anything to the car to drive it so I've been busy enjoying it, unlike all my other cars I've bought in the past Quote Link to comment Share on other sites More sharing options...
NewZed Posted August 28, 2013 Share Posted August 28, 2013 So what would it be like to drive the car with the current rear end, and the 5 speed out of a 77-78? Phantom answered this in Post #7. It would be exactly like what you have until you shifted to 5th. Look through the MT chapters of the various FSM's or find a web page that lists the gear ratios for the older versus newer 5 speeds. They're different, that's why the rear gear ratio is different. Quote Link to comment Share on other sites More sharing options...
Phantom Posted August 30, 2013 Share Posted August 30, 2013 (edited) "So what would it be like to drive the car with the current rear end, and the 5 speed out of a 77-78? Would it be worth it to swap or should I put it on the back burner until I get a matching rear? The rear is making knocking sounds going over bumps and when you shift (suspension clunk) so eventually I have to dig into that anyway. It has all new bushings and such except the mustache bar bushing so I think thats where the problem lies." The current rear end will work fine with a 5-spd out of a '77-78. It will work better if you use an 82-83 set-up. The "clunk" you are getting out of the rear end on shifting is the front differential mount. It is a typical problem in older Z's. The stock mount has a rubber isolator that rots out and allows the nose of the diff to rise up and smack the underside of the car during shifts. You can get a new one from Motorsport Auto or any of several other aftermarket Z places. Edited August 30, 2013 by Phantom Quote Link to comment Share on other sites More sharing options...
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