84 720 kc project

[izzo]

they aren't terrible thick, but are at the same time. Their shape and squarish design / cross sections gives them strength.

[mattmctree@gmail.com]

phew. good to know. i figures as much but didnt know if it would be rotting from the inside out

 i blew a whole bunch of mouse nests out of it. i figured there might be baffles along the frame but everything managed to blow right out

[datzenmike]

There may be baffles. I tried to poke a long wire rod through mine to remove all the scale and I couldn't. The frame was completely stripped down with not a thing bolted to it. Sanded down and rust painted. I settled for hosing it out as best I could and at the end of the summer (presumably dry) I squirted engine oil in there to coat it.

[mattmctree@gmail.com]

so after a few years i finally got my 84 720 4x4 out of the back field and into a garage. i took the transmission out in order to change the clutch and when i drained it i noticed some pretty decent sized chunks of metal on the drain plug. ( about 3/4 or and inch long and 1/4 in thick). i bought this truck and it had not run in 10 years so i do not know the history of how it shifted? is the transmission pooched? i wouldnt want to install it all over to find out i have gears gone. also a little tube off the top of the transmission was rotted off. im assuming its a breather port? should i be concerned about it or can i run it with the tube gone?

 

this is a learning experience for me as i have never worked on cars to this extent before.

 

[datzenmike]

 

This was a piece of bearing cage. I emptied one transmission and ball bearings fell out. The transmission is already out so pop it apart and have a look. Maybe this is why it was parked????

 

http://community.ratsun.net/topic/8809-how-to-remove-tranny-front-case/

[mattmctree@gmail.com]

cool thanks. are they difficult to take apart. i am fairly new to this stuff. also i read in the fsm that i should sand the flywheel with a light emery cloth. any idea on what the best grit to use is? the original flywheel had a groove in it from the rivets of the clutch plate but i found another one that is in good shape. would a flywheel be worth getting machined for a spare or are they generally just thrown out when they have wear/

 

thanks

[datzenmike]

http://community.ratsun.net/topic/8809-how-to-remove-tranny-front-case/

.

I've taken the front case off in a wrecking yard in 10 min. with only a 12mm socket/ratchet and a pair of snap ring pliers.  I would take longer if I was putting it back together.

 

220 grit on a small block of wood and knock down any high points and take the shine off using a circular motion. .

[bryant2482]

i have taken mine apart twice before. very easy to do. i had to rebuild it with new bearings. keep in mind that if you do end up putting new bearings and synchros in, the best thing to do is have a wide open clean area to lay out everything the way it came off, that way it will give you an idea of what goes where and in what order

[mattmctree@gmail.com]

awesme thanks. i got a spare flywheel im gonna put on, i took the old one off with an impact gun, when installing the new flywheel do i need the special tool from the fsm to prevent the crank from rotating or can i stop it another way. the engine is still in the truck if that has any bearing on it.

[ronnny]

So the bearings at the front are easy to change.  How hard is it to get to the bearings at the steel center plate to change?  I think if it were easy enough like the front it would be worth doing to my truck.  Or do the center bearings mess up like all the pictures i have seen others post of the front bearings being messed up

 

Thanks for all the pictures of taking the front case off yall.

[bryant2482]

the center bearings on the adapter plate are a bitch in a half to take off, unless you have a bearing press! you never wanna take a hammer to any of these parts lol, only if your replacing them

[ronnny]

ok let me put it a little different.  How much more after the front case is removed do you have to do to change the bearings in the steel center block.  I do not really want to have to disassemble and re assemble the whole main and counter shafts.  A press is no problem.  Is there a link to a writeup or video of this.  Thanks

[mattmctree@gmail.com]

any ideas on how to stop the crank from turning while torquing the flywheel bolts?

[izzo]

a socket and wrench on the flywheel bolt.

 

I use a drop of lock tite on the bolts, screw in by hand... Then use a stubby wrench and a 5lb hammer to torque them down. Never had one break, or come out unless I wanted it to.

[izzo]

^^ I meant on the crank pulley bolt :lol:

[datzenmike]

Take valve cover off and slide a socket extension through the cam sprocket hole.

[mattmctree@gmail.com]

awesome. thanks. i will take some pic as i progress in my project

[mattmctree@gmail.com]

the extension through the timing chain sprocket worked great!. ive got the rear extension off and am now having trouble getting the front case off. ive taken off the realese bearing and fork and removed all the bolts however its stuck on tight! any tips?

im going to try and rebild the transmission myself, ive noticed a couple of gears have their teeth chewed up so i will be needing to replce them. is this a hard thing to do? if anyone else has done this id love to get some tips

[datzenmike]

This will likely answer your question... http://community.ratsun.net/topic/8809-how-to-remove-tranny-front-case/

[mattmctree@gmail.com]

I have the rear extension and the front case off now. the reverse idler gear ( ?) has its teeth ground off and it looks like abnother gear in the back section is chipped aswell ,what is acceptable wear for a gear? or should i replace both.

i also noticed that the counter shaft bearing in the adapter plate it broken apart. it is hard to replace gear and the bearings? i dont have the use of a press or a vice at the moment .

[mattmctree@gmail.com]

So this is my first time doing this and I'm having a bit of trouble.i pulled my transmission and replaced the pilot bushing and all the clutch components but I'm having a hell of a time getting it back on. My truck is up on stands and I'm trying to lift the tranny up and slide it in place thought the clutch plate. I can't get it to seat all the way onto the studs. I pulled it back out and noticed that the pilot bushing and the edge of the crank are marred a bit like the main shaft is hitting it. I don't want to mess it up so I thought I'd ask some of you guys for advice on the best way to re install the tranny. Any tips much appreciated.

[cdub42]

stabbing a tranny is always a pain in the ass. itll line up and slide on, but if the splines on the input shaft arnt lined up to the clutch arnt lined up it will do just what your describing. also double check with your clutch plate alignment tool that the clutch is lined up with the pilot bushing. after a few failed stabs your clutch could have shifted. personally i remove the engine with the trans attached whenever possible. datsun engines are pretty easy to pul after the first time.

[captaingamez]

push harder!!!

 

also helps to have two people, the tranny in my maxima took exactly 20 minutes to put in

[Eagle_Adam]

did you use a clutch alignment tool? 

[datzenmike]

did you use a clutch alignment tool? 

This...

 

 

Is it in neutral? This will help slightly. Funny the last time I put a tranny in my 620 I got the tail up and onto the rear cross member, then lifted the front up level and started it forward and ... lost my grip on it. The nose slid forward by itself and right into the pilot bushing and the case and block banged together... alI I did was rotate slightly to line the bolt holes up!!!! Woot, never did that before or since.