KDMatt

Alright, so what voodoo black magic incantation do I need to recite to get the transmission back up into the car? I've got it hoisted into relative position using ratcheting tow straps (which I thought was pretty clever in lieu of getting another person,) and the splines have slipped into the clutch, but I can't get it to go the last inch, almost like it can't clear something (flywheel teeth?) I've been muscling with it for hours... spinning it, changing the angle, raising the car, lowering the car, raising the tranny, lowering it... I don't know what else to try. I've been kicking it and banging it and it just will not go. What are the tools of the trade for a guy re-installing a transmission on his garage floor? Thanks. Hopefully we're in the home stretch now. EDIT: Chas, this isn't related to my question, but I found a number stamped into the bellhousing that began with 720... more fuel to the speculation that we're dealing with a 720 5-speed I imagine.

It's less wiggly now that the I have the rubber boot in place, but ok good to know on sealing where the little pivot ball is. I haven't put the transmission back into the car (yet), so I can pull that off of there and seal it up quick. You might have just saved me from yet another headache! Thank you! Also, since replacing the clutch was the genesis of this whole venture, I finally got around to doing that. There's, like, nothing left of the old clutch, so even though this has been a monumental project, I'm really glad I'm doing it.

Got it all buttoned back up. I put the shifter in, and everything is clicking nice and solid like it should. No weird noises as I spin the shaft and work through the gears. Only question I have left is about the little "fork" that pushes against the throw-out bearing. It feels a little "wiggly" but I'm not sure if that's going to be an issue, since it's the pressure plate that keeps it all pushed back into place, right?

Oh no, don't misunderstand me. I know there's no need to pull the diff to check the ratio. My diff is leaking a bit, that's all. I figured, with the driveshaft disconnected it might be a good opportunity to pull it out, drain it, pop the cover, and reseal it, that's all.

I suppose since I'm suffering from "while I'm at it" syndrome, I could try to pull the diff out and see if I can figure out what the rear-end ratio is.

Looking at this spreadsheet (http://www.gracieland.org/cars/techtalk/gearing2.html), it looks like a the gear ratios (at least gears 1 through 4) are identical to the 240/260 transmission ( F4W71B) The same ratios were also in the 620 it looks like (as a 5-speed) though again, I can't find anything like the ratio for my 5th gear, as you mentioned, so I suppose it's possible something got swapped around at some point. Who knows.

Oooh, so you think it might be an oddball 720 transmission? This was originally a car from the southern US, not sure how that particular owner would have come across an 820 transmission here in the states... I don't think they were particularly common here, but that was before my time so I'm not of liberty to say. ... and yes indeed, I think my re-assembly has gone well so far. Only problem I had was one of the metal pins attaching to/securing one of the forks didn't want to get punched in all the way, no matter how many times I tried to redo it. It came through enough on the other side that I doubt very much it's in any real danger of shearing off. I should grab a picture of it though. Maybe I can find a replacement. I have no idea how much force they're really designed to cope with. Thank you for the spreadsheet btw. SUPER USEFUL!

Alright, I've got all the gears and shafts put back together. The clutch forks are back in, and once I get some silicone sealant, I'm ready to put it back in the housing. No extra parts - nothing missing! So far so good. Also, random question... How the heck do I calculate the gear ratio? I counted all the teeth (except reverse) and when I start dividing I end up with some SUPER weird numbers. Here's what I got, when counting the teeth, from front to back Main: 21, Counter: 32 Main: 26, Counter: 28 Main: 28, Counter: 19 Main: 33, Counter: 14 Rev: (Didn't count) Main: 22, Counter: 38 (Overdrive??) Thanks for your help everyone!

I suppose a simple test to see if it's electrical or mechanical would be to disconnect the plug for the #6 injector -- if you still get issues after removing electrical power from that injector, then it would be reasonable to assume it's mechanically "stuck open" ... if you no longer have "gushing" gas after disconnecting it, then it's electrical. Do you have a copy of your factory service manual? The PDF's have been distributed heavily over the years and are widely available online. Regardless of what you do next, if I were you, I'd be tempted to remove all the plugs, pull the fuse for the fuel pump, and just crank the motor over a few times to make sure there isn't any extra fuel sitting in the cylinders... when I hear "gushing" in the context of fluid coming out of the cylinders, I'm not immediately instilled with confidence. Enough gasoline in there, while trying to crank, and you could do some damage. Fluid sitting in a cylinder could also explain the strained/slow cranking speed. You're going to want to do an oil change after this is over too. I'm also chiming in because I see that you're in Minnesota, and I was curious if you were part of the Z-Owners of Minnesota group. I think you said earlier in the thread that you were in Washington County -- I'm in Minneapolis, so I'm probably not super close to you, but there might be some other folks in the group who are closer that might be willing to do a drive by. I know diagnosing 40-year-old EFI can be tricky by yourself if you've never done it before.

Hey gang, sorry to leave you all hanging on my progress. I managed to use the gear puller and "improvise" a way to get that shaft bearing off... which involved some metal pieces with pre-drilled holes (thanks to the hardware store) ... which extended it out the needed 12/13" to pull the bearing loose. I used a 1" wrench to go between the puller and the bearing so I wouldn't harm it. After that, I was able to get everything else off (keeping it all in order of course) so I could whack the main-shaft out of its bearing. The countershaft fell out early in the process (because of the broken countershaft bearing) which meant I had to use a screwdriver and a punch to pound out the outer bearing ring, and my vice and some heat to get the inner ring off of the countershaft itself. With those things both free, I got the new bearing into its home (6503 with C3 tolerance, came in the mail yesterday!) and used a punch to make sure it was seated completely around the edges. After that it was a matter of gently pushing both shafts back into their respective bearings and pounding them in all the way. I had a brief hiccup with the main-shaft, since there's a shim or washer of some kind that has to slip over a little ball-bearing lock, so I had to back out and re-align it, but once that was where it needed to be, I was home free. I didn't really molest or disassemble the front parts of the main-shaft nor countershaft in any way, so it should be good to go. I've attached some pics of everything meshing up. Do I look okay here? Only hiccup is that I forgot to slide a shim over the backside of the countershaft as I slid it in... so now I have to remove the reverse idler (which I was trying to avoid) to slip it on there. D'oh! Is there anything else I should be looking at or keeping an eye out for as this thing goes back together? Thanks again for your help so far everyone.

I actually had this thought as I re-examined the medium sized gear-puller I've got... that if I had some sturdy-enough metal pieces I could extend the "jaws" of the puller and try my luck that way... which I should do anyway because I'm sure getting that bearing back on is going to be just as much of a pain as it is/was to get off. I'll let you guys know how it goes. Thanks for sticking with me.

Hey, @Dave WM thanks for the link to these videos, dude, this one in particular was really insightful: That said, I'm still not having any luck getting the bearing off. I need this dude's tool!! @EuroDat I tried to replicate your tool with some wood and long bolts, but I can't apply enough pressure without the wood bending and cracking (and I'm using 3/4" plywood -- leftovers from when I re-decked my boat) @Mark Maras I tried using a punch, but I can't get a clear angle on it. I tried using my 1500watt heatgun to try to get the thing hot enough to knock out of place, but it still won't budge. I think I'm going to need to find a 12" gear-puller or something. :/ I just can't get enough leverage on the bearing. I'll keep you guys posted.

@Dave WM Thank you for the video link. I'll check that out when I've got some time at the office. @EuroDat aaaahhh so THAT'S what that thing is for! I saw that picture in a previous thread but didn't put 2 + 2 together. I don't have a lot of metal-working tools at my disposal -- I'll have to improvise. Thanks guys!

@EuroDat Cover up the stopper-pin with some sealant? OK. That's simple advice. Thank you! Got another quick question for the crew here. What's the best way to pull off this bearing that's kind of out here in no-man's-land on the shaft? The gear puller I've got isn't nearly long enough. Other than that, I'm slowly getting into it. Clutch forks and rods are out, as well as all of the little balls. I've kept everything neatly separated and labeled with a paint sharpie where and when applicable. Just need to figure out how to get this sucker off before I go any further. Also that nut on the main-shaft, IIRC, is reverse threaded right?

No worries, I think I'm in good hands now. I spent an hour just getting things cleaned up and organizing -- putting parts and pieces into bins and containers -- to make sure I'm keeping track of everything before I go forward. I also mocked up the shafts with some wooden dowels screwed into a piece of scrap plywood, this way I can keep all of the gears, snaprings, shims, etc. etc. in order, straight and organized. Got some heavy-duty snapring pliers too, along with some new safety glasses and work-gloves to commemorate the occasion. I hope I'm doin' you guys proud.

Chas, holy crap dude you freakin ROCK! This is a big big help! Also, as a note, I don't think I have one of these: Otherwise, I've got the bearing, the gutter, the rear oil seal, and the gasket ordered up. The picture of the back gears removed is really illuminating. I still have a long way to go it looks like.

Holy crap he does! BOOM!

Hey Chas, I'm not sure I'm seeing the correct bearing reflected on this list and in this diagram. I see the main-shaft bearing (#32276) but nothing listed for the one below it (which is the one that's broken on mine.) You're correct though, the number on the busted bearing is 6305, and I've already poked around some local suppliers (online) and it doesn't seem like it will be hard to source. Will any 6305 do, or is there something specific I should look for? ... and here's a random thought/idea/question (I'm at work, so I don't have the assembly right in front of me)... Is it possible to disengage all of the gears/bearings from the rear-half of the transmission (including the reverse idler) and slide both shafts toward the front at the same time, keeping them meshed and assembled? ... at least far enough to get that busted bearing out and put a new one in? I don't like to half-arse things, but I also want to minimize the amount of disassembly I have to do, lest I get something wrong. Just a random thought. The reason I brought up the 720 was because after hours and hours of endlessly googling different combinations of Datsun and Nissan transmissions, the closest one I saw (that still wasn't an exact match for mine) was out of an '80 720. ... and your warning on aftermarket parts has not fallen on deaf ears, I promise! The transmission was in pretty good working order before I pulled it, so I don't want to replace anything that doesn't seem broken. If it ain't broke... It never ground or stuck -- the only issue I ever had with this transmission was that it would make a wobble or "whine" noise when I let the clutch out in neutral, which could very well have been the worn countershaft bearing wiggling around a bit. I got a new throwout bearing as part of my clutch kit just in case, so that'll be covered too.

No worries, no offense taken. I was just feeling pretty good about this project overall (i.e. feeling like I'm not in over my head just yet) and your reply got me a tiny bit discouraged, so forgive me if I seemed a little too defensive in my reply. I felt like things were going swimmingly and you just had to remind me to not get cocky, haha. As for reading, I'm sticking to the FSM and looking over Dave's thread at the same time. What else were you referring me to read? This was the only mention of the "mystery part" I could find in that thread, btw: -- and I see now it's related to shifter return spring (though I think the FSM refers to this as a plunger) which I did remove as per the FSM instructions. I'm honestly trying to take this slow -- to be as methodical as I can -- I stopped where I did because I don't want to get lost. I suppose every man's got his limits, and I do genuinely appreciate you guys trying to keep me on track.

For the record I haven't come close to throwing anything away. The only thing in the trash right now are heaps and heaps of shop towels, soggy with gear oil. "Just had some loose metal in it" sounds strange to me. I was under the impression that we're talking about a pretty severe failure. Are you suggesting that I button it back up as-is and keep my fingers crossed? I'm honestly just poking around in here to see how hard it would be to fix. I don't feel like I've disassembled anything to that point yet where I'm clueless if I want to just slap it all back together (save for the "mystery piece" that I'm checking Dave's thread to reference.) Just saying. This whole venture from the get-go was meant to be more exploratory than anything. I'm still not above trying to source a different 5-speed and call it a day. I might still be at a point where I can take this assembly down to the transmission shop and ask real nicely to have them replace just that one bearing, who knows. Look, I defer to all of you guys on here because you know more than me. If I'm clearly in over my head on this one, I'll stop.

Hey Dave, thanks again for chiming in here. Okay, so that part goes into the back. It would make sense that it came out -- there were still bits of chewed up bearing jingling around in the back half, so I gave it a few gentle shakes to get it all out, and must have knocked this thing loose also. I'll try to figure it out where it goes. The back half of my trans is a different design than yours though -- I don't have that removable plate that's secured with two bolts that lets you get at that rod from the side. All things being equal, I'm probably going to leave much of the rear housing alone, save for replacing the rear-most seal. There's actually a spot on the underside of the trans tunnel on the car where you can see trans-fluid hasn't just been leaking out, but has been flung at speed, presumably for decades. Also got fluid leaking when the prop-shaft came out too. Oh and since my rear housing is different than yours, I will definitely check for that trough, but yes if you can find me that part number that would be awesome! Did you see my note about suspecting this might be a 5-speed out of a 720? Just curious. Well right now the whole countershaft moves around a lot, owing to the fact that the bearing hold it in place is destroyed. Speaking of which, I'm assuming I can just go ahead and order a 6305 bearing now? There are some local bearing supply shops that can get one for me in a day or two. There was a shim stuck to one of the bearings on the front (that came off under the cover) -- I saved it. I'm sure there are many more shims I'll need to keep track of. I do not have a caliper, nor do I have punch... yet. I think I'm also going to need a better set of snap-ring pliers. It sounds like I'll be making another trek to harbor freight. What are some tools of the trade I should arm myself with if I intend to keep going? Definitely trying to take my time and take lots of pictures. I think I might also go into the garage tonight with some ziplock bags and a sharpie and start labeling where components came from, just so I don't lose anything I've got so far. This is probably up there with some of the more complicated things I've ever done. Can you clarify what you mean on the seal-lip? Just speaking generally about installing new seals on things? Thanks again for all of your help.

Okay guys, I got it! (So far anyway) Turns out the bolts used to hold the bellhousing to the engine block are the same thread as the little ball-pivot thing... so I screwed one of those into the hole, grabbed my vicegrips and yanked the cover off. After that I had a bit of a struggle with the big main-drive snap ring, but eventually got that too. I used a screwdriver and a rubber mallet to gently whack (not pry) the bellhousing off. I took a few pics. Now that everything is apart, what else should I look for as far as wear is concerned? With everything free like this there is pretty substantial play in the countershaft. Do I need to take everything apart to get to that bearing... or is there a way I can gently remove just the countershaft? Other, procedural question ... how do I hold the shaft still so that I can remove the nut(s) at the end(s)? I stopped for the night because I found a part on my workbench that I don't remember removing. (Looks a bit like a cap -- I took a picture of it) ... what is it? Thanks for the help so far everyone!! EDIT: After doing some digging, I'm thinking this is most likely a 31.5" tranny out of an early 80's 2wd 720 truck (the short/stubby transmissions were only in the 4x4's) It seems to be the closest match as far as casing is concerned. I'm not having a whole lot of luck finding any additional info on it though (i.e. gear ratios, etc. etc.)

I had that thought too -- I don't have a bolt with the same thread though, at least not on me. I was thinking about trying to grip it with some vicegrips and just gently wail on it with a hammer. I saw a guy who apparently used a long screwdriver and a mallet to knock on the bolt of the ball-pivot to knock the thing loose -- not on the ball-pivot thing itself of course. The terminology of all this is going to drive me nuts.

Don't worry, I'm not too far into it yet that I don't know what goes where or what does what. I've haven't started disassembling the guts of the transmission yet. I'm just at the "let's take it apart and see how hard this is going to be" stage. This is also why I'm posting pictures of everything as I go, so if I DO get lost during re-assembly, I've got a reference. I've got the chapter for the FSM pulled up, there just aren't a lot of pics. In my last post, my 'stuck' place was the cover, and because the snapring for the shaft is underneath I can't pull the case off yet. I'm asking a lot of questions to make sure I don't beat on something that isn't meant to be beat on, or that I'm not taking something apart that isn't meant to be taken apart. Also since there's a question mark on what kind of tranny this even is, I'm just trying to be slow and methodical. Thanks for the pic btw, I think I've got some similar illustrations in my '76 FSM. Hey, you're that Dave WM guy I've heard so much about, hello! I've seen your videos on YT and appreciate you chiming in on my thread. Do you have a part number handy for that oil gutter ... just in my case I damage mine during disassembly? Also, on the point of the gasket seals for the tranny, do you recommend using some silicone stuff to seal it all back up once all is said and done? Also noted -- I won't try to pry it apart. Thanks again, guys. I'll try to see if I can get that bellhousing off tonight and then we'll see where we're at. If I can get it apart, maybe I can at least figure out what the part# on the bearing is I need to replace, so I can try to have it by next weekend... that would give me the week (if I wanted it) to get a feel for taking this thing apart. Famous last words: "How hard could this be?"

I think it's the same length as a standard Z transmission -- that is to say, I've got a replacement driveshaft for my Z, and it's the same length as the one that just came out of it... at least it sure looked like it. I'll have to double check now. Maxima in the 70's and early 80's would have been the 810, right? I've started dis-assembly, and I've reached a bit of an impass with the front cover -- I got all the bolts off, but I can't get the cover itself to budge. I got the back cover off (I can see two of the bearings/cages and so far these ones look ok) -- and I can see some starbit/hex bolts ... do those need to come off to get the front cover off? I can take some pics tomorrow of where I'm struggling if need be. Thanks for all the help so far everyone. I never would have made it this far without you guys. EDIT: I measured the transmission -- it's 31 inches... so... standard Z-length as far as I can tell. The bell housing looks like the Maxima bell-housing, but with the early Z 5-speed rear-half... The two ears are the giveaway on that right? Also, I think I found my busted bearing culprit... It's the one right in the middle down below (second pic) ... is that the countershaft?