Huntin720 Posted February 5, 2015 Author Report Share Posted February 5, 2015 Yeah so far I think the damage is limited. I'm not driving it so it won't get worse. It's not leaking at all. Either way hopefully I can salvage this one. I'd just like to drop a different one in while I'm at it so I don't have the down time and two build days. I commute in this truck so every day it's down is a day my wife is stranded at home and not happy. 1 Quote Link to comment
Huntin720 Posted February 5, 2015 Author Report Share Posted February 5, 2015 So one way or another I'll probably be over with this one to rebuild it. 1 Quote Link to comment
datzenmike Posted February 5, 2015 Report Share Posted February 5, 2015 Long 5 speeds that will fit the 720 4 x4... '80'81 S110 (200sx) mid ratio '82-'83 S110 (200sx) close ratio '81-'82.5 720 2wd mid ratio '81-'82.5 720 4x4 wide ratio Long 5 speeds that will work if you swap a Z series front case on it... '77-'78 280z mid ratio '79-'83 non turbo 280zx mid and close ratio '78-'84 810/Maxima mid ratio '84-'86.5 S12 (200sx) If '84 on you will likely have to swap the counter bearing. Also if 2wd, the speedometer pinion will need to be capped to prevent oil dripping out. 2 Quote Link to comment
Huntin720 Posted February 11, 2015 Author Report Share Posted February 11, 2015 Ok I bought a transmission today from a guy on CL. It was the right price. It is however a short shaft from an 82' so at the very least I need to track down a longer driveline. If anyone has one they want to part with I'm interested. Also I will have to swap the front case. I suspect that it isn't going to be any less work than if I just fixed the bearing that's trashed on the transmission that's on the truck but I'm learning things so it's cool. I didn't grow up working on cars and trucks so I don't feel bad when I don't know something. I'm thinking that it might be nice to have the shorter transmission on the truck if I need to work on the clutch at some point etc. A couple of things that I'm wondering. Are there basic things I should maintain while I have the front case off the donor? Are there other things I should do while the transmission is off the truck, since it's a pia to take off? Am I missing something so far? 1 Quote Link to comment
wayno Posted February 11, 2015 Report Share Posted February 11, 2015 The shift lever is going to be 5 inches farther forward than where a longshaft transmission shift lever is. There wasn't a short shaft made in 1982, so if it is a short shaft, it's likely a couple years newer which is good. 3 Quote Link to comment
Stoffregen Motorsports Posted February 11, 2015 Report Share Posted February 11, 2015 One cheap trick I do to old transmissions is to take the front cover off (inside the bellhousing) and remove the gasket completely, then reseal it using black or grey RTV only. The thickness of the gasket is removed thereby tightening up the backlash in the main and cluster gears. It sort of adds life to an old trans. Before you glue it all together, put the cover on (without a gasket) and spin the trans. If it feels tight, then I would go with another gasket. Also, taking a trans apart and rebuilding it is in no way as complicated as doing an engine. It is purely mathematical with almost no nuance needed, as opposed to installing a piston down a bore without breaking a ring. Gears are gears and they go where they go. There can be wear in the thrust washers (the thick hard metal washers on the shafts with the slot in them for the ball detent) and if you put them in backwards that can cause problems. Other than that, taking a trans apart is an exercise in making stacks. Stacks that make sense when you look at them as to where they go. If you have a new trans to install, take an afternoon and try blowing this one apart just to get familiar with it. The hardest part will be getting the nut off the tail shaft. I make my own tail shaft nut sockets. I cut the right size socket in half then weld a piece of tubing in between so I can use a rattle gun to remove the nut and then a torque wrench upon re-assembly. 2 Quote Link to comment
Huntin720 Posted February 11, 2015 Author Report Share Posted February 11, 2015 I'll post a pic of it tomorrow. It's definitely a short shaft (26" long) so who knows where it came from. Hopefully I didn't get hosed in some other way.With the shift lever being further forward how do I adjust for that? 1 Quote Link to comment
wayno Posted February 11, 2015 Report Share Posted February 11, 2015 You have to make a new hole for the shift lever, if you have a console, that is going to be an issue, you will need the shorter console. Do you have the long box or short box truck? When you pull the front case off, you should put a new Japanese bearing on the counter shaft/clustergear shaft, it's right there, and easy to do if you have a puller, otherwise like I said, you can bring it over here and we can put a transmission together. You know that your longshaft might only need a bearing, and if that was changed, you might be able to just put your old one back in. 1 Quote Link to comment
Huntin720 Posted February 11, 2015 Author Report Share Posted February 11, 2015 Wayno I know I'm probably overdoing it. I'll pull mine off and then let you know about when I can come by and take advantage of your generosity. Best case scenario I end up with two working transmissions and either have a spare or can sell one. Everything about this truck is short except for the trans., 1 Quote Link to comment
Huntin720 Posted May 23, 2015 Author Report Share Posted May 23, 2015 Work has finally slowed down to a point where I can get back to this project. I now know why everybody says to just pull the engine and trans together rather than try to do it from below on a 4x4. I'm pulling the front diff so that I can get it out of the way to drop the trans. The question I have is how to remove the suspension crossmember. I haven't had a torsion bar truck before so I don't know what is and isn't under tension. Right now I have the front end lifted on ramps. Do I need to lift it by the frame to pull the crossmember? Can I just undo these four bolts and pull it out? Im really hoping that I don't need to deal with the torsion bars to get this done. 1 Quote Link to comment
Gradyfest Posted May 23, 2015 Report Share Posted May 23, 2015 No need to touch the torsion bars. 1 Quote Link to comment
Huntin720 Posted May 23, 2015 Author Report Share Posted May 23, 2015 VICTORY IS MINE. I'll post pics when I get a chance but I just came inside to let y'all know that you can take the 31" transmission off the 1980 720 4x4 from underneath without pulling the motor. You shouldn't, of course, because it's ridiculous... But you can. Once the drive shafts, the suspension cross member, the front differetial, the rock guard, the exhaust, the starter, the clutch slave, and like 100 bolts are off and neatly categorized in ziplock bags, then you have to turn the transmission 90deg on its side (to clear the shifter striking guide from the body) and rock the motor back and forth as you slide the bell housing down past it at an angle. It might have been easier if I took the pressure plate off before trying to rock the trans past it. There was some rubbing. I'm also pretty sure that it wont come off if you have the motor properly supported because I had to tilt it forward and back to get past it. Quote Link to comment
Lockleaf Posted May 24, 2015 Report Share Posted May 24, 2015 Most of us have done it out the bottom on the 4x4 once. That's how we've all discovered the nightmare you just survived. Don't worry, putting it back together will be almost as much fun as getting out. :) Congrats on the success! 1 Quote Link to comment
Huntin720 Posted May 24, 2015 Author Report Share Posted May 24, 2015 Oh I'm sure it will be. I can't wait to try to get it to line up and bolt back on under there. But now I'm on a mission. Quote Link to comment
Stoffregen Motorsports Posted May 24, 2015 Report Share Posted May 24, 2015 Be careful when rocking the motor back and forth. You can tear hoses, wires, bend brackets, break stuff in general. I don't know your skill level, but if the trans doesn't stab into the clutch with ease (maybe a tiney effort) then try something else. You can bend the clutch disc by trying to shove it in there at an angle. I've also seen pelnty of pinched wires and speedo cables from people attempting forced entry. Take your time. 1 Quote Link to comment
Huntin720 Posted May 24, 2015 Author Report Share Posted May 24, 2015 All important wires and hoses are new (and flexible) and I made sure to keep things clear of any pinching. I recognize that it wasn't ideal by any stretch. For the re-install I am bringing in a friend with more experience. I figured since I'm doing a bunch of repairs at the same time I could handle it if I broke something taking it apart, but for assembly I plan on being more careful. I may even pull the clutch so the trans has room to slide back into position then replace it just before I push the two together. Quote Link to comment
Stoffregen Motorsports Posted May 24, 2015 Report Share Posted May 24, 2015 You can't install the clutch with the trans in the way. As a matter of fact, don't even pull the clutch unless you have a clutch alignment tool And somtimes the machine shop will balance the pressure plate to the flywheel, so look for stamps or paint or make your own so you know which way the pressure plate was mounted to the flywheel. Quote Link to comment
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