justin 620 Posted January 15, 2011 Report Share Posted January 15, 2011 Hello there, I have a 79 620 that came with a 5 speed, due to problems with the 5 speed I had to pull it and replace it. I recently got a donor truck for the transmition. The truck itself has no I.D. tags on it, so I don't know year or model, but it looks like a 73ish 620. When i pulled the tranni it wasn't the one I expected at all. Unfortunately I don't have the old tranni on hand so I can't compare directly, but I DO know this is not the same transmition by any means. What i would like to know, is if this transmition will bolt up to my motor. I do have the clutch, pressure plate, and fly wheel for both trucks, so if I have to mix parts to make it work it's fine. The flywheel won't work, due to mine being 6 lug and the other being 5 lug. Any help would be much appreciated Quote Link to comment
datzenmike Posted January 15, 2011 Report Share Posted January 15, 2011 That's an 04 '72 to 10 '73 F4W63 4 speed identical gearing to the one in the 510 wagon. First that tranny is about 5-6" shorter than the 5 speed you removed. You will need a longer drive shaft. Possibly the one in your parts truck will work. It's a two piece so only the front half is needed I think. Yes it will bolt up to the L20B on your '79. No, neither the other clutch nor the flywheel will fit the L20B so... Keep the '79 clutch and flywheel on it. Use the '79 5 spd. throwout bearing collar on the shorter transmission. Or get one. The one on the shorter transmission is matched to the 200mm clutch and you will be keeping the 225mm on the '79 motor and it won't work with it. Probably you can use the parts truck cross member/tranny mount. The tunnel has a cover plate. Probably the parts truck one will need to be swapped with the '79 truck for the different shifter hole location. Speedometer cable will now be on the opposite side but the longer 5 speed cable should easily reach it. Unfortunately the '79 did not have the same ratio differential as the parts truck so the speedo drive pinion will be geared wrong and your speedometer will read slower than to are really going. Change the tail stock output seal. They're only $5 and saves doing it later when the tranny is in. Tranny should be drained for removal and is a lot easier to install when empty. Refill with new GL-4 80-W-90 gear oil that is 'yellow metal safe'. Quote Link to comment
76bullit Posted January 15, 2011 Report Share Posted January 15, 2011 Always listen to Mike, he knows his shit!!!! Quote Link to comment
420n620 Posted January 15, 2011 Report Share Posted January 15, 2011 Always listen to Mike, he knows his shit Datsuns!!!! Fixed, true statement. Quote Link to comment
justin 620 Posted January 15, 2011 Author Report Share Posted January 15, 2011 Thanks Mike! Now, my uncle has concerns with the pilot bushing? Would this be an issue or not? And the shorter transmition shouldn't be an issue because I do have the longer front section on hand and can put it on this one. And I have about 5 gallons of tranni fluid and it already drained it, so I'm set with that stuff. Quote Link to comment
datzenmike Posted January 15, 2011 Report Share Posted January 15, 2011 The pilot bushing is the thing that looks like an inch long piece of 1/2" copper pipe and is tapped into the end of the crankshaft for the front tip of the tranny input shaft to ride in. The old one is probably fine but they are only $3-$5 and like the seal in the back , much easier to change while the tranny is out. As mentioned, do you have the release bearing and housing from the 5 speed??? The top part or collar holds the bearing on the bottom. The collar length is matched to the size (diameter) of the clutch assy. The one in the parts truck is matched to a 200mm clutch and won't work properly with the 225mm now in your truck. If you can find the 5 spd one it will work... and I suggest you replace the bearing on it now before assembling. It's cheap insurance against pulling everything out in three months because it has failed. . Quote Link to comment
Guest DatsuNoob Posted January 15, 2011 Report Share Posted January 15, 2011 I always believe in replacing small parts when doing a big job. Seems like going cheap on the little shit sets you up to do things again faster than you expected. I know a good trick for getting out pilot bushings using a bar of soap. Might be able to find it on youtube better than I could explain it. Quote Link to comment
datzenmike Posted January 15, 2011 Report Share Posted January 15, 2011 I always believe in replacing small parts when doing a big job. Seems like going cheap on the little shit sets you up to do things again faster than you expected. I know a good trick for getting out pilot bushings using a bar of soap. Might be able to find it on youtube better than I could explain it. Yup, soft bar soap like Ivory works way better than grease. :D I use a small 6" chisel or screw driver and lightly hammer it in lengthwise down the length in 2 or 3 places and the pieces fall right out. If it scratches the inside of the hole it's not a big deal as the bushing is very soft and will drive in just the same. The pilot bushing is made of bronze powder that is pressed into shape by hydraulic pressure and then heat treated. The final product is somewhat porous and is oiled and does not need further lubrication when installing. Quote Link to comment
datzenmike Posted January 15, 2011 Report Share Posted January 15, 2011 TO CORRECT SPEEDO ERROR: The one in that transmission should be a BLACK plastic 17 tooth cog Pt.# 32703 22001. What you want to try is a Yellow 16 tooth cog Pt.# 32703 22000. This will spin the speedo faster to read a higher MPH from the 4.11 rear end. Probably the one on the left is what you have now. The difference between the parts truck rear end ratio 4.375 and the '79's 4,11 is 6.05%. The difference between a 16 and a 17 tooth pinion is 6.25%.... close enough. Always count the cog teeth to be sure. Oh the 16 tooth is from the F4W63 transmission in the 510 car. Quote Link to comment
justin 620 Posted January 16, 2011 Author Report Share Posted January 16, 2011 Alright, well I got it in yestarday, Need to get bolts and nuts for the starter before I ran it, but when I get those I'm going to test the set up and see if anything's amiss, if it is I'm gonna pull it and fix anything that's wrong. I have another speedo pinnion, but I'll have to campare it to the one that's in the tranni now. The one that I have to replace it loks like the one in the middle, I'll count the teeth and see if it'll work. Quote Link to comment
datzenmike Posted January 16, 2011 Report Share Posted January 16, 2011 Probably the one on the left is what you have now. If memory serves me the far left one is from the F4W63 and the other two are from the FS5W71B and are (obviously) shorter and unlikely to work. Pull and compare. Also did you use the release bearing collar from the 5 speed??????? Quote Link to comment
justin 620 Posted January 17, 2011 Author Report Share Posted January 17, 2011 No, it was too long, we press the collar out of the bearing and replaced it with the shorter one from the 4 speed. Quote Link to comment
datzenmike Posted January 17, 2011 Report Share Posted January 17, 2011 That's why I mention it. The collar is matched to the clutch not the tranny. You kept the same clutch on the '79 so you need to keep that collar and use it on the parts truck tranny. Quote Link to comment
justin 620 Posted January 17, 2011 Author Report Share Posted January 17, 2011 Crap, So I have to use the collar from the 79 instead of the collar from the parts truck? Quote Link to comment
datzenmike Posted January 17, 2011 Report Share Posted January 17, 2011 As mentioned, do you have the release bearing and housing from the 5 speed??? The top part or collar holds the bearing on the bottom. The collar length is matched to the size (diameter) of the clutch assy. The one in the parts truck is matched to a 200mm clutch and won't work properly with the 225mm now in your truck. If you can find the 5 spd one it will work... and I suggest you replace the bearing on it now before assembling. It's cheap insurance against pulling everything out in three months because it has failed. . The parts truck should have a longer collar than the '79. The 200mm clutch on the parts truck should be shorter from the flywheel up to the PP diaphragm fingers and will need a long collar. The 225mm clutch is taller and requires a slightly shorter collar. This is so the clutch arm works within the same range and doesn't have to 'reach' in as far to work the PP. Quote Link to comment
justin 620 Posted January 17, 2011 Author Report Share Posted January 17, 2011 The one from the 79 is about 1/2 an inch longer then the one from the parts truck. But I used the shorter collar from the parts truck with the flywheel and clutch assembly from the 79. Quote Link to comment
datzenmike Posted January 18, 2011 Report Share Posted January 18, 2011 That would seen to be correct... Well try it and if the clutch does not fully disengage then the longer one will have to go in. If you have to remove take a picture of them side by side. Maybe everything will be fine. Quote Link to comment
justin 620 Posted January 18, 2011 Author Report Share Posted January 18, 2011 I'll try this setup first, no sense in taking it out just to find out it was correct. And I was thinking about taking pics and making sure first, but I was in too big of a hurry... Guess I learned that lesson. Quote Link to comment
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