Found metal at the bottom of my 5-speed. What next?

[KDMatt]

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. 

[Zed Head]

Well then, there are numbers stamped on the ring gear.  The number of teeth on each gear.

Grease the half-shaft u-joints while you're at it.

[KDMatt]

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? 

[Zed Head]

Yes, the fork and TO bearing are wiggly, but make sure that they are both properly clipped in to place.  The TOB on the fork, and the fork on the pivot ball. Also, did you seal the threads on the pivot ball?  I ad a transmission that leaked from there and had to pull the transmission again.  The threaded hole ends in the fluid area.

[KDMatt]

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. 

 

[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. 

Edited May 15, 2016 by KDMatt

[EuroDat]

You are almost there. If the splines have slipped into the clutch disc, than the only thing holding it back is the spigot or pilot bearing (nissan calls it the first motion shaft bush) in the crank shaft. If you didn't take the pressure plate off it should be perfectly in line.

If you remove the clutch and put in back on, you must align the clutch disc. Otherwise it will fall down about5 to 8mm and the first motion shaft will be way off alignment.

Sometomes I use a couple of 100mm lengths of threaded bar in the bottom two bellhousing bolt holes. Works well for me when Im on the ground. It helps with alignment and if you can't get then in, you have an alignment problem. If you use threaded bar, get a hack saw and cut slots in the end so you can use a screwdriver to get them back out.

Did you do anything with the clutch disc? If so I would check the clutch disc alignment. Look at the pressure plate finger and position yourself so the pilot bearing is in the centre. The clutch disc must be a perfect spacing around the pilot bearing. This is how I line mine up because I don't have a alignment tool.

If not didn't remove the pressure plate, then it is probably just too must rigidity. The tranny is strapped to the jack. Try to find some bolts roughly twice as long as the ones that came out and us them in the bell housing. Don't tighten them, just use them to stop the transmission from falling off. Take the straps off the transmission and lower the jack a little (1 - 2 cm). Get behind the transmission and wiggle it up and down left and right while pushing it home. At a given moment it will go click and pop in. Thats when the input shaft finds the pilot bearing.

[KDMatt]

New Clutch, New Pressure Plate. I used the alignment tool to keep the clutch in place, but I suppose it's possible that it's slightly off-kilter. Do you really think that could be what's keeping me from getting it all the way up there? 

Also, I found a thread over on the ratsun forums where someone was talking about 720 5-speeds, and this person mentioned a truck transmission with the exact ratios I've got (including the strange .882 fifth) http://community.ratsun.net/topic/40535-1985-720-5-speed-tranny/#entry639082 ... makes me think it might be a completely unmolested 720 5-speed... just still playing detective over here! 

[EuroDat]

Btw: The input splines are probably clean and dry from doing the bearing on the transmission. Use a small amount of grease on the input shaft splines. Not too much or it could fly oof into the clutch disc and cause shudder later on.

The clutch disc slides back and forth on these splines when it releases and engages. It's very small amout of movement, but dry splines will hinder this and the clutch can rub on the pressure plate when disengaged and cause grinding in reverse and hard to get into gear.

If you have a brass pilot bearing a small amount of grease on that won't hurt. It can be a bearing or a bush.

[EuroDat]

2 minutes ago, KDMatt said:

New Clutch, New Pressure Plate. I used the alignment tool to keep the clutch in place, but I suppose it's possible that it's slightly off-kilter. Do you really think that could be what's keeping me from getting it all the way up there? 

Yes I do. This is your problem. It came out so it will go back in. Those clutch alignment tools are approximate guides (IMHO). That is why I just use my naked eye and line all three (plate fingers - disc splines - pilot bearing). It only has to be a 1mm out and you will have trouble.

The pilot bearing has to support the tool, something it is not designed to do. Any play between the pilot bearing bush and the tool or ball bearing wear and play between it and the tool will allow it to drop a little and result is disc out of alignment. Check it with your eye to confirm. When you put the tool in, is it in the center of the pressure plate fingers?

[KDMatt]

Okay, that's good to know.

This is my first clutch job, so it's completely possible I didn't do it 100% right. I'll slip the transmission back down and lower it to fuss with the pressure plate and alignment a bit more. I'm going to be mad (but relieved) if it's something that simple! Also, I'll do a dab of grease on the splines -- that makes sense too. I do the same on the lower-unit for my boat... it's beyond me why I didn't think to do it here.

[EuroDat]

You can try unstrapping the transmission from the jack first. Give yourself a bit more freedom to move the transmission around. Hold it by the rear extension housing and wiggle it while pushing it gently home.

If you take the transmission back out. Check the clutch disc with your fingers. Run you fingers around the outside of the pressure plate and feel the clutch disc. If its out of alignment you should pick it up there. If it is, then loosen the pressure plate enough so you can push the disc around with your fingers. Check it with your eye or using the alignment tool and check it has equal distance around the pressure plate fingers.

This problem can hold people up for a while. The first one is a learning process. One you don't forget easily If you need to do it again, you will remember.