521 re-redone DD

[wayno]

This was an explosion waiting to happen.

 

If something vibrates it needs to be fixed, things could have happened that were way worse, you are lucky.

[.sunlover]

2 hours ago, wayno said:

This was an explosion waiting to happen.

 

If something vibrates it needs to be fixed, things could have happened that were way worse, you are lucky.

It's not like I just chose not to worry about the noise.  I had been under it, several times, tinkering with this and that, trying to find/fix the source of my subtle vibration.  When the vibration became not so subtle, the driveline had walked back away from the tail end of the transmission, and I knocked it and locked it forward, so it could still move, but not so far that the dust covers no longer overlapped.  It didn't vibrate (not really) on the way home.  Next trip, BOOM.  So yeah, what I thought was the cause of the vibration, was more likely the effect.  Shit happens.   I will say that it is nice to see the same people still doing their thing, just like when Ratsun.net was my Facebook. (and before Facebook was something I avoid).  Around 2010, give or take.  Datsun Mike, expert on almost everything Datsun, especially compatible transmissions.  Wayno, the purist, who also puts his rigs to work, big time.  Bonzai, the dder, who has put up some great videos, like the timing one.  If you remember me from back then, please forget, lol.  I am very different as a sober person.  Also, less confidence and more knowledge, experience and skill.  Alcohol is a big confidence booster, especially in the portions I was consuming.  9 years sober, now.  I've been to a safety meeting or 2 since then, but for me, the trick was to become comfortable with myself, so I didn't feel I need anything to be content or avoid self-reflection that would ultimately make me feel bad about myself (Justifiably).  My point is, that I am aware, now.  Aware that vibrations are bad and need to be fixed.  That would be more useful for the drunk stoner I was.   How would you know that, though, if you remember the old me?   🙂  now ya' know.  Again, it's great to hear from you guys. 

[banzai510(hainz)]

i had a vibration once. i jack up the truck and put in gear and saw vibration.2bolts missing .then find out they also sae sizes on 521s except motor. You done good and fast if back on road. I personlly hate 521 trans set up. Pulln all that shit out nearing 60yrs old isnt good. I got 2 toyota p/u. 91 and 92. They not as cool as 521 but way better rigs

[Rustbin]

1 hour ago, .sunlover said:

I am very different as a sober person.  Also, less confidence and more knowledge, experience and skill.  Alcohol is a big confidence booster, especially in the portions I was consuming.  9 years sober, now.  I've been to a safety meeting or 2 since then, but for me, the trick was to become comfortable with myself, so I didn't feel I need anything to be content or avoid self-reflection that would ultimately make me feel bad about myself (Justifiably).  My point is, that I am aware, now.  Aware that vibrations are bad and need to be fixed.  That would be more useful for the drunk stoner I was.   How would you know that, though, if you remember the old me?   🙂  now ya' know.  Again, it's great to hear from you guys. 

 

A lot of us need to reach that point of becoming comfortable with ourselves, for me it came about when I reached 50, it wasn't alcohol but relationships. Now I can focus on things I want in life, like working on my Datsuns and doing metal work. Thank you for coming back.

[.sunlover]

48 minutes ago, banzai510(hainz) said:

i had a vibration once. i jack up the truck and put in gear and saw vibration.2bolts missing .then find out they also sae sizes on 521s except motor. You done good and fast if back on road. I personlly hate 521 trans set up. Pulln all that shit out nearing 60yrs old isnt good. I got 2 toyota p/u. 91 and 92. They not as cool as 521 but way better rigs

Thanks!  Yeah, it took 8 days to source a new transmission and install it.  I of course still had to do my regular work.  5 more days and I found and installed the driveline, and it's a good driving truck, again.  Tranny swapping a 521 is pretty awful.  That non-removable cross member is the worst part for me.  Oh, and this time, I couldn't use my buddies' machine/auto shop, because they are growing into a 3rd unit in the business complex they are in.  They bought a massive machine and the stuff they had to get out of the way is stacked in the lift bay.  I was working under jack stands on muddy gravel in occasional rain, snow, and hail.  Toyotas are good rigs.  I dropped a tranny out of an 81 corolla and a 98 4runner, but not 90 91.  the 81 was pretty easy, but the 4runner wasn't.  everything is wired in, no wire connectors, and it's big and heavy.   Oh, and both the strut rods for my 521, at the pick n pull were bent.  I could straighten them, but they would be weaker.   I am getting some made, soon, anyway.  They were the same length as in my 521. 

[.sunlover]

1 hour ago, Rustbin said:

 

A lot of us need to reach that point of becoming comfortable with ourselves, for me it came about when I reached 50, it wasn't alcohol but relationships. Now I can focus on things I want in life, like working on my Datsuns and doing metal work. Thank you for coming back.

Thanks, good for you Both are great ways to spend time.  Glad to be back.  I'll hit 50 late this year.

[NC85ST]

A week to source and install a transmission? Amazing! Where I live that would be impossible, a month maybe. Congratulations on being 9 months sober, that’s even more amazing. Keep up the good work.

[NC85ST]

Sorry, meant 9 years.

[wayno]

18 hours ago, .sunlover said:

It's not like I just chose not to worry about the noise.  I had been under it, several times, tinkering with this and that, trying to find/fix the source of my subtle vibration.  When the vibration became not so subtle, the driveline had walked back away from the tail end of the transmission, and I knocked it and locked it forward, so it could still move, but not so far that the dust covers no longer overlapped.  It didn't vibrate (not really) on the way home.  Next trip, BOOM.  So yeah, what I thought was the cause of the vibration, was more likely the effect.  Shit happens.   I will say that it is nice to see the same people still doing their thing, just like when Ratsun.net was my Facebook. (and before Facebook was something I avoid).  Around 2010, give or take.  Datsun Mike, expert on almost everything Datsun, especially compatible transmissions.  Wayno, the purist, who also puts his rigs to work, big time.  Bonzai, the dder, who has put up some great videos, like the timing one.  If you remember me from back then, please forget, lol.  I am very different as a sober person.  Also, less confidence and more knowledge, experience and skill.  Alcohol is a big confidence booster, especially in the portions I was consuming.  9 years sober, now.  I've been to a safety meeting or 2 since then, but for me, the trick was to become comfortable with myself, so I didn't feel I need anything to be content or avoid self-reflection that would ultimately make me feel bad about myself (Justifiably).  My point is, that I am aware, now.  Aware that vibrations are bad and need to be fixed.  That would be more useful for the drunk stoner I was.   How would you know that, though, if you remember the old me?   🙂  now ya' know.  Again, it's great to hear from you guys. 

 

You said, "the driveline had walked back away from the tail end of the transmission", this makes me think the center support(rubber piece) was destroyed, this would allow it to walk back on the spline of the rear section of the driveline, the way the tail shaft broke makes me think this had been going on for a while, I expect there was likely a clunking going on also.

 

If you still have a vibration and you lowered the truck, you need to figure out the proper height for the center bearing height.

[banzai510(hainz)]

when one lower the truck unbolt the carrier bearing and see how much it raised and make a spacer and or longer bolts. If this is over 4in blocks in back i bet this was the issue

[.sunlover]

I didn't lower it.  PO did.  Looks like 1.5" blocks.  Bushing is NLA, and not terrible.  It has some years on it, but only 50k miles.  it's in the driveline picture.  with the thing bolted down, it's pretty tight.  Not so much, when it's not bolted.  But, it's NLA, so, I hose clamped both sides of it, to restrict the movement.  Now, since it only moves at the slip yoke, no more hose clamps.  Please prove me wrong about that bushing being NLA.  I would love to be wrong about that. Taiwan has all the cab seal rubber, but no carrier bushing that I could find.  It seems like it will now slide inside the carrier bushing, when it goes over bumps.  Snug might be the best tightness for it.  Bolted tight and just snug.  That's what I've got.

[Crashtd420]

10 minutes ago, .sunlover said:

I didn't lower it.  PO did.  Looks like 1.5" blocks.  Bushing is NLA, and not terrible.  It has some years on it, but only 50k miles.  it's in the driveline picture.  with the thing bolted down, it's pretty tight.  Not so much, when it's not bolted.  But, it's NLA, so, I hose clamped both sides of it, to restrict the movement.  Now, since it only moves at the slip yoke, no more hose clamps.  Please prove me wrong about that bushing being NLA.  I would love to be wrong about that. Taiwan has all the cab seal rubber, but no carrier bushing that I could find.  It seems like it will now slide inside the carrier bushing, when it goes over bumps.  Snug might be the best tightness for it.  Bolted tight and just snug.  That's what I've got.

I did a write about for a replacement carrier bearing.... 

Go down the page to the b2000 information... 

https://ratsun.net/topic/80193-datsun-521-carrier-bearing-replacement-option/

 

[.sunlover]

8 hours ago, Crashtd420 said:

I did a write about for a replacement carrier bearing.... 

Go down the page to the b2000 information... 

https://ratsun.net/topic/80193-datsun-521-carrier-bearing-replacement-option/

 

Thank you

 

[wayno]

On 3/26/2025 at 9:30 PM, .sunlover said:

I do not know what that is on the driveline closet in the photo, but that is not a 521 center support, when installing that driveline the round piece with the rubber has to fit tight in the center mount, if it is tight the driveline cannot back out of the transmission as that piece on the driveline is supposed to be tightly mounted on the drive shaft.

 

Was the center mount mounted to the cross member tight?

 

It appears the 620 driveline(farthset away in photo) does not have the center support piece either, where is the rubber support?

Edited March 30, 2025 by wayno

[datzenmike]

This is the 620 rubber surround and it DOES allow some forward and back movement because it does not have a slip yoke on the rear most driveshaft. If there is a small amount of forward and back at the differential from suspension flex or during acceleration and braking then the spline can slide in and out of the transmission.

 

 

The PL521 front driveshaft is SOLIDLY bolted to the transmission and any forward and backward component of the differential is taken up by the slip shaft in the rear driveshaft.

 

 

[wayno]

I suspect he has a 5spd with a slip yoke installed on the 521 driveline same as I did on my 521 work truck, my center support had a 521 rubber surround, it allowed very little forward/rearward movement, Sunlover said he had to slip the yoke back forward into the transmission at some point to get home, this just does not seem possible unless the center rubber support was free to move around.

[.sunlover]

41 minutes ago, wayno said:

I do not know what that is on the driveline closet in the photo, but that is not a 521 center support, when installing that driveline the round piece with the rubber has to fit tight in the center mount, if it is tight the driveline cannot back out of the transmission as that piece on the driveline is supposed to be tightly mounted on the drive shaft.

 

Was the center mount mounted to the cross member tight?

 

It appears the 620 driveline(farthset away in photo) does not have the center support piece either, where is the rubber support?

What I have is the thing on the 521 driveline, slid forward of the carrier bearing.  It is what I got when I bought a new carrier bearing and bushing for it, about 25 years ago.  the metal around it unbolts and comes off of it.  Just the rubber is in the picture there.  The 620 driveline had an open hole where the bushing was supposed to be and a somewhat similar housing to what I have.  I wouldn't think I have a different bushing, since it bolts perfectly into place on the 521, but I guess it's possible.  I really think the thing to focus on is that it is there, it fits and bolts down correctly, and it does allow for a little movement, like a 620 driveline setup requires.    Thanks for the help.  I'm going to go drive my Datsun, now.   

[datzenmike]

I agree. The driveshaft was moving back and collapsing into the slip yoke. I bet the rubber surround is totally gone. The 620 surround will move but maybe an inch both ways.

[.sunlover]

1 hour ago, datzenmike said:

This is the 620 rubber surround and it DOES allow some forward and back movement because it does not have a slip yoke on the rear most driveshaft. If there is a small amount of forward and back at the differential from suspension flex or during acceleration and braking then the spline can slide in and out of the transmission.

 

 

The PL521 front driveshaft is SOLIDLY bolted to the transmission and any forward and backward component of the differential is taken up by the slip shaft in the rear driveshaft.

 

 

Wow, so weird.  Mine and the wrecking yard 620 carrier bushing and housing are similarly different.  Mine allows for some movement, so I'm calling it good.  It's hard to remember the details of a 25 year old purchase that was one of many I was making at the time.  Thanks for the info.

  

[.sunlover]

Ok, I will be driving with the imaginary rubber bushing that is in the driveline picture there.  I guess I will imagine it's driving nice and smooth too.  Just like you guys are imagining that after 30 years of automotive experience that I don't know the difference between a missing bushing and a snug one that allows for some movement.  Even when there is a picture of it.  

[banzai510(hainz)]

last time i was under my 521 i think my bushing was soft. maybe thats why it leaks oil out rear seal. i changed it twice. i just add oil. its a pain taken that output shaft out. Wish i got a 510wagon when nobody wanted one. Way ezer to maintain

 

[wayno]

OK, this is the only photo I have of the rubber piece in a truck, this is my 720 which has a larger rubber piece, the piece was so bad(deteriorated) that I put rubber hose pieces around the inside of it so it would hold it in the correct place as I did not like the clunking and more importantly I did not want it to explode and possibly have a catastrophic event like losing the driveline and have it come out from under my truck and hit something, or have it completely raise the back of the truck up and finally breaking off the rear axle, I can only imagine bad things happening.

I had a drive line come out of my 1965 Nova/4spd with a 350hp one time power braking on the start line, I was lucky no one was on the side of the car, it flew 30 feet sideways.

 

 

 

That rubber piece keeps the forward/backward motion of the driveline happening in a 521 with a rear slip joint, one could say the 620 driveline without a slip joint will not move forward or backwards, without that rubber piece in the joint it can wobble, at high speed that wobble could take you out of the picture.

[.sunlover]

I have run out of ways to attempt to let you know that the bushing I even took a picture of, does indeed exist, and is working perfectly for the application it is designed for.   Feel free to go on ignoring everything I say and the picture of it.  I have been driving it daily for a week now and it is fantastic.  No clunk, no wobble.   Do you know why?  It is because it does exist and is working great.   after 25 years, it allows for some movement.  Bad for a driveline that slipped at both ends, but great for the 620 style.  What do I know, though?  I'm just the mechanic that owns it, is looking at it, working on it, driving it, taking pictures and telling you several times, in perfect English what is going on.  My patience is spent.    

[datzenmike]

If the rubber surround was in place and working then the front driveshaft couldn't have wandered more than an inch or so to the rear. What do you think?

[.sunlover]

It was in place.  the limiting factor for how far forward it can walk was where it would hit the bushing housing.  It was hose clamped around the bushing that does exist, on both sides, like I have said.   first to keep it from walking forward, then to also keep it from walking back. I think that the one time it walked back (like I mentioned) and made a horrible vibration, and I fixed that by knocking it forward and adding the 2nd clamp to prevent that, it was far enough back to either aggravate an existing crack or make one.  After I did that in the hobo freight parking lot, I drove home a short distance just fine, but the next time I drove it, BOOM.   I told you that it was there, described the condition, took a picture, repeated myself and was as clear as possible, explained that I am sober and have been for almost a decade.  What did you think?  I'm too stupid to know the difference between a bushing being in place and an open hole where it's supposed to be?  That seems to be the story you are going with.  That's not supposed to be insulting to me?  That is the most logical explanation?