Forum newb and his 34K original miles '80 Datsun 720 4x4

[Gradyfest]

I have a concerning noise I need help with gentleman. There is a bearing going bad in my transmission. It's getting worse and I need to address it soon. The thing to help identify it is that when I push the clutch to the floor I here it roll to a stop. What bearing could it be  :confused:

[wayno]

That would likely be the cluster gear bearing, but I suppose it could be the main input shaft bearing also.

You need to quit driving it and fix it before you need a new transmission, you can likely fix it right now with just a bearing.

 

[Draker]

I'd drop the tranny and inspect the front bearings and the throw out. All are pretty easy fixes.. as long as you catch it early like Wayno said.

[Gradyfest]

Ok. Looks like I'm dropping my tranny this week. Do you guys know where I can buy these bearings? I'd like NISSAN OEM if possible. I'm sketched out to drive it now, so it'll sit until I do the damn thing. I also assume I'll need some kind of bearing puller... I can just rent one of those... I wonder if my trucks high enough to just drop it in the drive way... Another guy and I can probably handle the weight... Did I pay the phone bill yet... (I'm just thinking in type.) This will be the biggest job I've done in a while...  :mellow:

[Draker]

You'll be fine. Just a couple bolts and its out. 

[Busta Nut]

I have a concerning noise I need help with gentleman. There is a bearing going bad in my transmission. It's getting worse and I need to address it soon. The thing to help identify it is that when I push the clutch to the floor I here it roll to a stop. What bearing could it be  :confused:

 

 

 but I suppose it could be the main input shaft bearing also.

 

 

^^....this.....

 

 

If it goes away when you push the clutch in then it is the input shaft bearing.......

 

Part number should be on the bearing......

[wayno]

I buy my bears at a place that used to be called "bearings inc", they are now called "Applied industrial technologies", I just take it in and they look at it/measure it and then go to the computer, when I go in, I ask for bearings "Made in Japan", they usually are the most expensive, but I don't want to have to pull the transmission again in 6 months.

[wayno]

^^....this.....

 

 

If it goes away when you push the clutch in then it is the input shaft bearing.......

 

Part number should be on the bearing......

Both the input bearing and cluster gear bearing spin together, when one stops, so does the other, so it's hard to tell which one is going out for sure, but generally if the noise changes when you put it in 4th, then it's likely the cluster gear bearing, because in 4th, the cluster gear bearing has no pressure on it, as all the power goes threw the main shaft, so it is usually quieter in 4th if it is the cluster gear bearing going out.

There are always exceptions to everything, if the bearing cage is destroyed, then it's going to make a lot of noise all the time except when not turning(push the clutch in and put it in gear, it should not make noise because the bearings are not turning).

[Gradyfest]

I buy my bears at a place that used to be called "bearings inc", they are now called "Applied industrial technologies", I just take it in and they look at it/measure it and then go to the computer, when I go in, I ask for bearings "Made in Japan", they usually are the most expensive, but I don't want to have to pull the transmission again in 6 months.

Score! I found one of these places forty minutes away from me. This is a job I'm going to be doing on a lift I've decided. I want to save my back. I'm studying the book and feeling more confident now that I can "picture" what's inside. That with knowing a place I can get the bearings has me feeling better. I'll get the fanciest shit hot bearings they have, I don't like redoing jobs either Wayno. I got a good start and haven't even touched the truck yet. Thanks everybody. Take a look at my study material with me won't ya...

 

 

 

 

 

 

 

[Gradyfest]

 

 

 

 

[wayno]

Here is a link to an article I wrote about how to make a shortshaft 5 speed, it goes threw all the steps that you will need to do to replace the lower front bearing, it's not that hard to do.

http://community.ratsun.net/topic/28473-how-to-put-together-a-shortshaft-5-speed-for-a-l20b/

[84720FourWheel]

The transmissions are fairly light, I can carry one by myself, but I would use a jack to support the transmission.

 

The 84 FSM suggests to remove the engine and trans as an assembly then separate. The bolts are easier to get to, and you can stab the trans more easily. You can also ensure that clutch components are installed correctly.

[wayno]

If it's easier to pull the engine/transmission in a Datsun/Nissan 4X4 rather than dropping the transmission out the bottom, then 4X4s are a pain, I always drop the transmission out the bottom of my 2wd trucks.

[Lockleaf]

Yeah wayno, it's actually much easier to pull through the top. To go out the bottom on a 4x4, you have to remove the front diff and cross member and deal with the exhaust in your way, etc etc

[wayno]

I thought about that last night, and I came to the conclusion that I would likely make a removable tunnel if it were a keeper truck for me, but I have no 4wd trucks, and the ones I had in the past were never/rarely used in 4wd, so I don't need one, I would rather have a posi.

Yeah wayno, it's actually much easier to pull through the top. To go out the bottom on a 4x4, you have to remove the front diff and cross member and deal with the exhaust in your way, etc etc

[Gradyfest]

I've been staring at my Datsun in the driveway waiting for some time off to get into it. That time is now! I'm loading up to take it in to a lift right now. I need to drop the transmission, find bearing noise, remove intake and exhaust to fix/find manifold exhaust leak, do valve lash, I think that's it... Oh, I'm also bringing my 1980 4x4 specific header in case I come across something crazy like a cracked manifold. Wish me the best! I'll take lots of photos for y'all. This should be fun.

 

 

 

[5150 Wll]

Your truck is BEAUTIFUL

[denmarkboy]

i cant wait to see this truck in person at Canby .

[Gradyfest]

Everything is going great and I'm having fun. I didn't actually turn a wrench until today. But I accidentally broke the air breather to my transfer case. Does anybody have one laying around? Or does anybody know where I can find one? I actually brought my transfer case home. I can tell it's been cracked before because it has blue RTV around it and it leaks. Same shady shit from the previous mechanic I come across now and then. I've known it's been leaking since I've owned it and have constantly checked and filled it when needed. But now that I'm taking everything apart... Might as well seal it right. I'm staring at it on the table in my house now. I'm about to reverse engineer this sucker like a Lego system.

 

 

 

 

 

 

 

 

[84720FourWheel]

38322-N0100

There's your part number. It's like 6 bucks if you can get it from Nissan.

[Gradyfest]

38322-N0100

There's your part number. It's like 6 bucks if you can get it from Nissan.

How did you do/know that? Nissanpartszone.com?

[84720FourWheel]

Yep. It's nissanpartsdeal now though.

 

I just use it for finding part numbers, because shipping usually evens out the prices, and the dealer can usually get it faster.

[Gradyfest]

I'd drop the tranny and inspect the front bearings and the throw out. All are pretty easy fixes.. as long as you catch it early like Wayno said.

 

So I got it all apart to find a terrible throw out bearing. Kool, cleaned up everything and put in a new one. I also took apart the transfer case that's been leaking since I bought it and resealed that since it was off. Also fixed a leak around the switch in the transmission. While I was at it I sand blasted everything or hand sanded and dremmeled, then went through the whole recommended two step chemical process on the stuff not blasted and coated everything in POR-15 with the POR-15 chassis black topcoat too. The cleaning and coating was the most work. Then today I finally got it all back together and fired it up!

 

Everything is great right! Wrong, the bearing sound is still there. While sitting in idle it was the same, rolling with an etch a sketch sound until I pushed the clutch in. I kept the throw out bearing and it obviously needed changed. But it was so disheartening to hear that sound still after all that work.

 

 

It's late, but I'm going to have to check out your link Wayno. You guys are right, pulling out the engine and tranny from the top would of been easier. If it wasnt for the leaking transfer case I might of went that route first. That's how I'm doing it next. Big question though, the actual 1980 720 manual says I still have to remove all that stuff to pull the engine with tranny connected? Have any of you guys actually pulled an engine from a 1980 4x4 720 and NOT removed all the 4x4 stuff? I would think I could just undo the propeller shaft from the transmission to transfer case and be good. The manual says to remove front diff and transfer case with all propellor shafts first?

[Gradyfest]

Something I'm proud of I want to share real quick with oics. I needed a special tool the manual calls a "companion flange wrench" to open my transfer case. Couldn't find any around and the universal ones online I managed to find were in the hundreds. Screw that, I made one. Had about 35 bucks invested in the end, (I had to pay a local guy to cut and weld four bolts in the holes I drilled. He also burnt the 2" hole in the center for me. I don't have a welder or hot enough torch.

 

 

 

 

 

[Gradyfest]

Teaser of before and after of the transfer case. All sealed up and not leaking anymore, looking sexy! Then that's it for tonight (this morning actually,) for realz. I'll try and get more photos up tomorrow, I have a lot from this job.