I'm tackling a clutch job for the first time in my history with this car (11 years/35k miles), and as such, I cracked the drain plug for the first time in at least that long. I have no idea when it was last done -- somewhere I've got a stack of records that would probably tell me if it's been done anytime "recently" in the car's history... but for now it's an unknown.

The fluid that came out was pretty sludgy and gray, and as expected there was a pretty thick layer of metal crud on the magnet plug, but, on top of that, I found a couple of bits/chunks of metal. 

I searched some previous threads and saw someone else with something similar -- it looks like some bits from one of the gear bearings? I have no idea how long these parts have been down there. For all I know these things could have been down there for decades. 

I'm assuming the worst-case scenario is that I need to crack open the transmission and rebuild/replace these assemblies. That being the case, is there a section in the FSM that covers how to do this? I've never cracked open a transmission before (hell I've never even done a clutch before - so I'm already in unfamiliar territory), but there's no time like the present, I guess? How big of a job are we talking about here? Could it be done in a weekend? An afternoon? 

If you were me, what would you do?

 

8 hours ago, KDMatt said:

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...

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?

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?

You really need to get a good set of instructions and keep track of what you're doing or you'll end up with a pile of parts, or extra parts when you're done, or break something.  For example, there's a snap ring on the main shaft bearing that has to be removed in order to get the front case (aka bellhousing, not cover, the snap ring is under the cover) off.  Doesn't look like you removed it (you didn't mention it, and you mentioned the Torx bolts instead).  The instructions will also identify the shafts.  The guys here are saying it's easy, but it's not "remove 5 bolts and replace a bearing" easy.  It's a "long series of simple steps" easy.  The MT chapter of the Factory Service Manual is your best starting place.

That looks like the bearing that commonly falls apart.  Good luck.

Here's an example.  The 1978 5 speed instructions will work.  Maxima manuals are hard to find.

Look in the forums Download area.  I'd post a link but the site is turtle slow today.

 

 

after getting that front cover off and the ring on the front bearing I had to beat on the front housing with a rubber mallet going all around it before it let go. The gasket seal that is used is like glue.

Edited May 8, 20168 yr by Dave WM

That's a good point.  Some PB blaster or solvent might soak in and loosen it up.  Don't stick anything between the pieces and try to pry though.  That will damage the sealing surface.

oh one more thing, the oil gutter is very easy to damage when removing or installing that front housing to the metal plate. It just so heavy and there is very little room for the gutter, its very easy to come into contact and bend it. I highly recommend you order one from Nissan just in case yours is broken damaged or gets mucked up during the install (get bent, not easy to tell, you have to be VERY careful on the install, and then see if you can look from the back side and make sure its still in the right place, its hard to describe, I heard mine rubbing on the gear AFTER the intall, and to separate, straighten out and do again). One thing I noticed is the steel of the new one (gutter) seems softer than the orig. The oil gutter catches flung off oil from the gear cluster and sends it down a trough that feed the bushing that the drive shaft end (smooth part) rides in. The bushing is right behind the rear oils seal, look it oveand see if its in good shape. Mine was  bit scored (I presume from lack of oil due to the broken gutter found stuck to the magnet) but not bad I was able to clean it up with some fine oil soaked sand paper.

Edited May 8, 20168 yr by Dave WM

9 hours ago, Zed Head said:

You really need to get a good set of instructions and keep track of what you're doing or you'll end up with a pile of parts, or extra parts when you're done, or break something.  For example, there's a snap ring on the main shaft bearing that has to be removed in order to get the front case (aka bellhousing, not cover, the snap ring is under the cover) off.  Doesn't look like you removed it (you didn't mention it, and you mentioned the Torx bolts instead).  The instructions will also identify the shafts.  The guys here are saying it's easy, but it's not "remove 5 bolts and replace a bearing" easy.  It's a "long series of simple steps" easy.  The MT chapter of the Factory Service Manual is your best starting place.

That looks like the bearing that commonly falls apart.  Good luck.

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.

8 hours ago, Dave WM said:

oh one more thing, the oil gutter is very easy to damage when removing or installing that front housing to the metal plate. It just so heavy and there is very little room for the gutter, its very easy to come into contact and bend it. I highly recommend you order one from Nissan just in case yours is broken damaged or gets mucked up during the install (get bent, not easy to tell, you have to be VERY careful on the install, and then see if you can look from the back side and make sure its still in the right place, its hard to describe, I heard mine rubbing on the gear AFTER the intall, and to separate, straighten out and do again). One thing I noticed is the steel of the new one (gutter) seems softer than the orig. The oil gutter catches flung off oil from the gear cluster and sends it down a trough that feed the bushing that the drive shaft end (smooth part) rides in. The bushing is right behind the rear oils seal, look it oveand see if its in good shape. Mine was  bit scored (I presume from lack of oil due to the broken gutter found stuck to the magnet) but not bad I was able to clean it up with some fine oil soaked sand paper.

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?"

 

 

Edited May 9, 20168 yr by KDMatt

People have said that you can remove the clutch fork pivot pin and run a longer bolt in the hole to push the cover off.  Sounds sensible.  The front cover has the same problem as the front housing, it's essentially glued on.

EuroDat/Chas has compiled a parts list out there somewhere, I believe.  Worth a search.  The bearing part number will be there.

3 minutes ago, Zed Head said:

People have said that you can remove the clutch fork pivot pin and run a longer bolt in the hole to push the cover off.  Sounds sensible.  The front cover has the same problem as the front housing, it's essentially glued on.

EuroDat/Chas has compiled a parts list out there somewhere, I believe.  Worth a search.  The bearing part number will be there.

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. 

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.)

 

Edited May 9, 20168 yr by KDMatt

the unknown part to help prevent shifting from 5th to reverse on the down shift, part of the rear case. I mentioned that in my trans when I was wondering if the hole should be on the top or the bottom. should be as spring somewhere as well, hopefully still on the bolt. This mounts the side of the case, has a kind of diamond shaped housing held on with two nuts.

The oil gutter is missing completely on yours so you will need. I will dig around and get that part number for you, you can order from courtesy Nissan. Check the rear housing see if there is a long trough that lead all the way back to the tail, it matches up with a hole in the plate that in you pic has nothing installed.

start at about 4:30 for the talk on the oil gutter.

I used some sealant that was advertised as for use in diff and transmissions. Tried not to use too much as it mostly will squeeze out anyway. You will of course want to get new seals all the way around, there are several, o rings too. Mine was leaking a lot at the shifter (inside) which prob is not a big deal as there is no real pressure and its not like its going to start dripping out, but still its easy to get at if you remove the striker rod and use it to knock out the steel plate on the back of the shifter. All this is covered in the video. Also you want to get a new front cover gasket of course. On thing I noticed what while tapping on the counter shaft nut its easy to slightly shift the entire counter shaft forward. I you do this just look at the alignment of the gears they should be fully meshed. even a tiny bit of movement you will see. look at them closely before any work gets started. To be sure I also measured the distance of the front counter shaft bear to front housing to confirm that the shim that was in there was still correct (this is covered in the FSM regarding what shim to use based on the measurement, use a caliper with the depth gauge). Oh Don't lose that shim (its prob stuck with oil to the front housing but will come loose). Looks like a large flat ring. BTW, I am a newb to this stuff as well, don't let it intimidate you, take your time, there are a lot of good folks here with good info that were very helpful to me that have done this before. The main thing I have found about working on any old tech (I do electronics as well) is to take your time, take pictures, document with notes, don't excessively force, and ask lot of questions if you get in a jam. Pay attention to how seals are installed, but generally speaking the seal lip (the open side of the seal) should go TOWARDS the media that your are trying to seal (oil/grease), at least that is what I have gotten after researching it. I know it prob obvious to mechanics but to a newb like me I was not sure.

Edited May 9, 20168 yr by Dave WM

3 hours ago, Dave WM said:

the unknown part to help prevent shifting from 5th to reverse on the down shift, part of the rear case. I mentioned that in my trans when I was wondering if the hole should be on the top or the bottom. should be as spring somewhere as well, hopefully still on the bolt. This mounts the side of the case, has a kind of diamond shaped housing held on with two nuts.

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. 

3 hours ago, Dave WM said:

On thing I noticed what while tapping on the counter shaft nut its easy to slightly shift the entire counter shaft forward. I you do this just look at the alignment of the gears they should be fully meshed. even a tiny bit of movement you will see. look at them closely before any work gets started. To be sure I also measured the distance of the front counter shaft bear to front housing to confirm that the shim that was in there was still correct (this is covered in the FSM regarding what shim to use based on the measurement, use a caliper with the depth gauge). Oh Don't lose that shim (its prob stuck with oil to the front housing but will come loose). Looks like a large flat ring. BTW, I am a newb to this stuff as well, don't let it intimidate you, take your time, there are a lot of good folks here with good info that were very helpful to me that have done this before. The main thing I have found about working on any old tech (I do electronics as well) is to take your time, take pictures, document with notes, don't excessively force, and ask lot of questions if you get in a jam. Pay attention to how seals are installed, but generally speaking the seal lip (the open side of the seal) should go TOWARDS the media that your are trying to seal (oil/grease), at least that is what I have gotten after researching it. I know it prob obvious to mechanics but to a newb like me I was not sure.

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.

the snap on the reverse gear is a MAJOR pita, don't think that one has to come off for the countershaft bearing replacement.

Get a decent dial caliper (not digital), a good tool to have. You will need the Nissan shaft and counter shaft nuts that need to be staked.

I can see there are a little keys and such from videos of disassembly, did not do that much on mine so cant help there.

on seals there is often an open side of the seal where you can see the spring that goes around the inside, it look like a U shaped channel.

You want the open side of the U to be facing what ever you are trying to seal in. On the front face plate for instance you need to drive the seal in from the open side not the back closed side (the open side faces the oil, the closed side faces the front cover). This means getting a tool like a large socket that fits the outside edge of the seal I used a very large socket and made sure it was pressing the outer edge of the seal. Also used my drill press like a regular press to push it in smoothly, rather than banging on it with a mallet. You want that seal seated evenly into the face plate. Now on the tail shaft you press the back side in since the oil is inside the tail case. Just Play close attention to how the seal are installed, they tend to pop out when pulling and then you may lose the orig orientation. Better still take a pic of the seal before removing.

Edited May 9, 20168 yr by Dave WM