stheodore10 Posted September 18, 2015 Report Share Posted September 18, 2015 Finally got my f5w71b ('79 280zx) transmission up and bolted to my l16. I was test fiting the driveshaft, taking different measurements for the shortening. This is where my problem lies. First of all, the differential side of the drive shaft bolted doesn't come close enough to the driveshaft bearing. Meaning when I dry fit the other half the bearing on the shaft is too far back and doesn't line up with the bearing holder. Either thus is the way it's supposed to be or I have the wrong drive shaft and have had the wrong one since I got the truck. I'm stuck. Should I have this shaft custom m are to my truck still? If so what was the procedure some o you 5 speed people used? If not what is my next move...? Thanks all Quote Link to comment
datzenmike Posted September 18, 2015 Report Share Posted September 18, 2015 Not enough info but I'll assume that with an L16 you have a '72-'73 620. The 620 through '74 used a short 4 speed. About 26" long. The 620 from '75 up used a long 4 or 5 speed. About 31.5" long. All 620s use a two piece driveshaft with a hanger or carrier bearing in the middle. The carrier bearing is located in the same place for all 620s so from the carrier bearing back to the differential is the same for all reg cab 620s no matter what transmission is used. A short transmission will need a longer front drive shaft to reach between hanger bearing and the transmissions. A longer transmission will need a slightly shorter front drive shaft. The difference in front drive shaft length is the difference in length between the F4W63 four speed and the FS5W71B five speed. (about 5.5") Fastest fix is the front drive shaft from a '75 and up. These had the longer 4 or 5 speeds in them and the driveshaft is already shorter. You can use the ones from a Reg cab, Long wheel base or King Cab trucks as the front drive shafts are all the same and only the rear shaft is different for the different length frames. Next easiest is shortening your too long drive shaft about 5.5" or the difference in length between your old four speed and the new five speed. 1 Quote Link to comment
stheodore10 Posted September 19, 2015 Author Report Share Posted September 19, 2015 Do we have a lead on where to find the Longtail driveshaft? My 620 is a 73. My issue I guess would be the rear driveshaft doesn't reach where the front shaft would be after being shortened/ using the short shaft. In other words the front shaft bearing sits too far in the support it looks like Quote Link to comment
datzenmike Posted September 19, 2015 Report Share Posted September 19, 2015 The rear end hasn't moved or where the hanger bearing mounts.The rear drive shaft will fit in it's original position. The front drive shaft should be shortened about 5.5" too long. Easier to show what's needed than try to describe. SHORT TRANS// ---FT. DRIVE SHAFT---------------HANGER BEARING--U JOINT--REAR DRIVE SHAFT--DIFFERENTIAL LONG TRANSMISSION// ---FT. DRIVE SHAFT------HANGER BEARING--U JOINT--REAR DRIVE SHAFT--DIFFERENTIAL Do we have a lead on where to find the Longtail driveshaft? Yes, already posted. Fastest fix is the front drive shaft from a '75 and up. These had the longer 4 or 5 speeds in them and the driveshaft is already shorter. If you are asking to buy one, it mustn't be done in any of the discussion forums. You can place an ad in the appropriate classified section... http://community.ratsun.net/classifieds/category/5-drivetrain/?sort_key=date_added&sort_order=desc Quote Link to comment
cruznude Posted September 19, 2015 Report Share Posted September 19, 2015 its real simple listen to what he is saying. Its all mechanics and we have to adjust things to the different applications that we are wanting. Quote Link to comment
stheodore10 Posted September 19, 2015 Author Report Share Posted September 19, 2015 I'm listening, I'm just prying to get more information. Also wanted to say that the support wasn't matching up properly with the shafts on a dry fit... but I will do more research I suppose. Thank you Quote Link to comment
datzenmike Posted September 19, 2015 Report Share Posted September 19, 2015 How much did you shorten the front drive shaft???? Quote Link to comment
stheodore10 Posted September 19, 2015 Author Report Share Posted September 19, 2015 I didnt, this driveshaft is what was hooked up to the f4, which I believe was factory? Quote Link to comment
datzenmike Posted September 19, 2015 Report Share Posted September 19, 2015 I don't know what the hell you're doing. Of course the drive shaft won't fit, it's got a longer transmission in there. Bolt the drive shaft to the differential and the hanger bearing will be in the right place. The front drive shaft won't fit into the transmission because it's too long and will extend forward beside it. Shorten the front drive shaft the difference in length between the old and the new transmissions. See post #2 for lengths. Compare them to the transmissions you have.... and post a picture of them to be sure that you have what you think you have. Quote Link to comment
stheodore10 Posted September 19, 2015 Author Report Share Posted September 19, 2015 There is a mistake communication here its alright though I got a decent amount of information, I appreciate it Quote Link to comment
datsunaholic Posted September 20, 2015 Report Share Posted September 20, 2015 Did this truck ever run when you had it? That's the only way I can see that the driveshaft (rear one) would now not fit. Or you somehow are trying to fit the 280ZX driveshaft in there, not gonna work. What you need is a '74-79 620 short wheelbase driveshaft assembly. The whole thing, from trans yoke to diff flange, both shafts. carrier, 3 sets of U-joints... If you have the actual original '73 rear shaft, the all you need is a 74-79 front shaft. I'd stay away from '74 ones though, I've had several folks say they had '74s with short transmissions but mine had longtail 71B trans (unless replaced with oddities) so unless you know what you're looking at you could end up with one too long. Quote Link to comment
datzenmike Posted September 20, 2015 Report Share Posted September 20, 2015 I didnt, this driveshaft is what was hooked up to the f4, which I believe was factory? The F4W63 is the stock 4 speed for a '73. It's 26" long. The '74 was the first year the 'new' 71B 4 speed was installed. It's 31.5" long, same as the later 71B 5 speeds including the '79 280zx you have. So put the rear driveshaft back in. If it came out it should fit back in. It's the front drive shaft that won't fit. There is a mistake communication here its alright though I got a decent amount of information, I appreciate it It's all very simple really. The rear end hasn't moved or where the hanger bearing mounts. The rear drive shaft will fit in it's original position. The front drive shaft should be shortened about 5.5" too long. Easier to show what's needed than try to describe. SHORT (F4W63) TRANS// ---FT. DRIVE SHAFT--------------------HANGER BEARING--U JOINT--REAR DRIVE SHAFT--DIFFERENTIAL LONG (FS5W71B)TRANSMISSION// ---FT. DRIVE SHAFT------HANGER BEARING--U JOINT--REAR DRIVE SHAFT--DIFFERENTIAL Quote Link to comment
stheodore10 Posted September 21, 2015 Author Report Share Posted September 21, 2015 I believe I found someone for a driveshaft, I'm going to try that route. If not I may be bringing this post back from the dead. Thank you both for the information Quote Link to comment
datzenmike Posted September 26, 2015 Report Share Posted September 26, 2015 .... so far,..... Quote Link to comment
stheodore10 Posted September 26, 2015 Author Report Share Posted September 26, 2015 Waiting on shipment of "new" driveshaft Quote Link to comment
datzenmike Posted September 26, 2015 Report Share Posted September 26, 2015 Aww... Quote Link to comment
stheodore10 Posted September 26, 2015 Author Report Share Posted September 26, 2015 Lol will update Quote Link to comment
edutechnic Posted January 13, 2016 Report Share Posted January 13, 2016 Swapped an NA, '82-83 280ZX 5 speed into my 3-speed auto, '74, L18 620 and it was a bolt-in affair. Just posting for science, and Google. Quote Link to comment
datzenmike Posted January 13, 2016 Report Share Posted January 13, 2016 There is a bolt in crossmember that the transmission mount bolts to. The same crossmember is used for automatics and standards..... Did you have to turn it around backwards for the manual mount? Quote Link to comment
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