620 5 Speed Problems

[Juan Valdez]

How goes it, Ratsun?  I have some problems and questions, and hopefully you guys can help.  First off, I have a '73 620 with an L20b and what the PO says is a KA tranny mated to a NAPZ bellhousing (5spd of course).  I don't know because there are no identifying numbers on the transmission, and I don't know how to eyeball these things.  That's where I'm hoping you cans can say yes or no on whether or not that is what I have.

 

Here are some external oics of my tranny.  She's yellow, so she must be asian:

 

 

On to the actual issues!  First off, my clutch fork bent and cracked.  I don't know why.  I posted on here last year about my slave cylinder pushrod not disgengaging the clutch enough to shift.  Well, now I know why.  It almost seems like that it is the wrong size...?  I measured from the dimple for the slave cylinder pushrod to the center of the main pivot, and it is about 4 3/4".  In case you need to know, I have a 240mm clutch.  I forgot to measure the length of the release collar, so I'll do that soon because I'm sure you'll need to know that too.

 

Here's a pic of the sad fork:

 

Secondly, and this is probably related, the shaft/collar that the throw-out bearing collar rides on snapped off at the base.  I'm not too happy about that.  Is there a Nissan part number for this cover, or is it even readily available?  If not, who has an extra one lying around that they want to sell me?

 

Here's some pics of this :poop: :

 

I really don't want to source a new transmission... what are the likely causes of Mr. Clutch Fork getting bent?  Wrong size something or another?

 

Thanks guys.

Rob

 

 

[darrel]

Looks like a 81-83 zx transmission. The front cover is probably aluminum. A 4 spd front cover will work and if the 4 spd is from a 4 cyl it may be cast steel. 

 

Not sure why the fork would crack like that, could be the 240mm flywheel and PP.

 

Looking at it again. The combination of the front cover breaking and fork cracking, there might not have been any grease for the TO collar to slide.

[Juan Valdez]

There definitely was NOT any grease for the TO to slide.  That's for damn sure.  That thing was dry as a bone.

 

edit:  and you're correct, it is aluminium.

[darrel]

There you have it. No grease, TO collar bound, breaking the front cover and cracking the fork.

[metalmonkey47]

Either that or the PO dropped the trans on the clutch fork, bound up the collar, and broke it off the front cover. Prolly not that though. just a though. 

[fivetenguy]

Yeah, definitely not a KA tranny. The PO either didn't know what he had or he lied to you :sneaky: ......

[LenRobertson]

I saw a clutch fork to a '78 620 at Pull n Save a couple of days ago. I may be there tomorrow and I can grab it if it is still there. A couple of guys were pulling the engine to get to the tranny. After they left I walked by and they left the fork, but took the front cover plate you need. I guess they didn't need the whole tranny, just that one cover. Maybe someone else will post that they have both the fork and the cover you need. Also, does anyone know if all the 620 forks are the same? Different for 4 or 5 speeds?

 

If you have a 240mm clutch, you need to be sure you have the correct length TO bearing sleeve for the clutch. I have Bookmarked charts of the 200mm and 225mm clutch sleeve dimensions, but not for 240mm. Maybe someone has that chart and can post it, or a Google search might find it.

 

Len

[Juan Valdez]

Thanks for the responses guys.  Yeah, the PO told me that it was a KA trans.  He sounded convinced, himself, that it was a KA but you never know.  I want to give the guy the benefit of the doubt because of who he is.  I'm all the way down here in San Diego, so don't worry about the fork Len, though I do appreciate the offer.  I'm just going to order one from Partstrain.

 

I still need to measure the throwout bearing collar to make sure that it is the correct sized one.  The PO used a threaded slave cylinder pushrod to increase the distance, which is why I'm not feeling to warm and fuzzy about the collar or the fork.

[DISLEXICDIME]

looks like  a napz trans mated to a l series bell housing

[darrel]

Check your clutch pedal. Make sure the hole where the master and pedal are pinned isn't elongated needing a longer throw.

 

Reading your other thread where you heard clicking, it may have been clicking because of the crack.

[LenRobertson]

Found links to 240mm clutch specs:

 

http://datsun510.com/photopost/showphoto.php?photo=6979&title=datsun-pressure-plate-comparison&cat=3129

 

 

http://datsun510.com/photopost/showphoto.php?photo=6980&title=225mm-and-240mm-clutch-t-2fo-bearing-sleeve-specs&cat=3129

 

Maybe you can figure out which TO sleeve you need from these pages.

 

Len

 

[Juan Valdez]

Thanks Darrel. I checked it yesterday and its good and I'm thought the same thing about the clicking as soon as I saw the damage. Nissan stocks the gearbox front cover, so I'm going to get down there to see if the have this exact one, and pick up a new fork while I'm at it.

[Juan Valdez]

Little update to close this out so people can use the info later...

 

Basically, poor maintenance, lack of grease, and age contributed to the failure.  More likely poor maintenance.  darrel was right in that no grease, heat/binding, snap-bang-clunk dead. 

 

• Not sure what the trans is, but it is definitely mated to an 82-84 NAPZ bell housing.
• Front cover for the trans is 32111-E9800.
• Nissan lists the same part number (30531) for the clutch fork for a number of model years and 5 spd transmissions, but I'm not sure about earlier 4spds.

 

Since I'm bumping this back up to the top, I thought I'd ask a new question about my center carrier bearing for the drive shaft.  I'm broke.  As in, "thousands of dollars in medical bills" broke and need to find a cheap solution to my bearing.  The actual bearing is good and spins freely - it's just the rubber isolator that's toast.  I've seen people use random rubber "things" in place of actually replacing the entire thing, but has anybody ever used a mountain bike tire?  I have an old downhill casing Kenda Nevegals that I thought I could wrap around the bearing, gluing the layers as I wrap, then clamp that bitch down.  Anybody have any experience doing this with decent results?  Thanks again.

[darrel]

I'm sure that would work, conveyor belt, and someone also used a coil spring spacer they bought at the auto parts store. That was within the past couple weeks.

[datzenmike]

There is a metal band that clamps around the rubber isolator. All you need is a long enough strip of anything rubber and firm. I cut an inch and a half (ish) wide strip of conveyor belt and wrapped it around to build it up. Kept trimming the length until the hold down strap would fit it and still be snug. If loose it will just fall out. I had planned this to be temporary but forgot about it for years.