Dana 18 Rebuild

Yeah, I measured. It was a bit over .001, but I dont have a bore gauge, so its just an estimate with the calipers I have. I got it together, but it was pretty irritating. I knew it was going to be difficult and I made sure there were no burrs on the inside of the D18 case.

Its amazing how long this swap it taking me. I am still not done yet. It really does not want to go back together. Had to walk away. Should have been a 3 hour leisurely job that is going into 6 now.

 

Transfer case is in. Works fine. Little bit of heat on the bearing caps, but I can put my hand on there and leave it there. Probably 150 degrees give or take. Already leaking from rear seal. The yoke is new with 1200 miles on it. The Novak kit didn't come with felt seals, but i don't know how much those do anyway. Reused the old one that was new with the yoke.

My old transfer case had a worn intermediate shaft. This one is obviously new. What started this whole process was a bang when I push in the clutch from the transfer case/transmission area.

ITS STILL OCCURRING!

I unload the pressure from the drivetrain when I push in the clutch and something goes THWACK and a lighter thwack immediately thereafter. Its not the transfer case mount. I checked it. I assume something has a lot of play and the feedback is causing it to make that noise.

Maybe there is too much play in the driveshaft slip yoke or the ring and pinion, even though I set that to spec.. Maybe its a gear slapping something in the SM420. Its driving me even more crazy than usual.

oh yeah, i also put in the wrong speedo gear. 15 MPH is about 25......

 

Thank you Howard. I used the seals that came in the Novak kit. They have no numbers on them, but seem to be OK. I am pretty sure that to replace the speedo gear I might have to wreck the seal, so before I change the gear, I will order a new one. The leak is the normal drip hanging on the bottom of the brake plate, so its not bad. No leak yet from the front yoke and that one is pitted and has a groove worn into it. Could have used the V6 yoke, but I dont have a V6 driveshaft or a Ujoint for it.

Similar amount of whine from Tcase as before, but not the super loud whine in 4 hi.

 

I just ordered a new seal. They dont look like the ones I got from Novak in the pics. I would have ordered 2 but they only had one in stock. I will have to unhook my speedo as any speed approaching 45 will peg it out. Might download a speedometer for my phone.

 

I always order National oil seal 450185 for front and back

 

i ordered National 472635

 

The pics of the ones I ordered look like they are open on the one side and not like the Novak closed ones. I am sure Novak is not making them, so who is?

 

The clunking noise is in the transmission. Got under the jeep, used my foot to push the tire back and put my hand on the transmission case. I can feel it and hear it. Clunk one way, clunk the other. Either worn gears, shaft, case where bearings ride or more likely, all of it. I put new bearing and synchros in it. Maybe SM420s are just like that. I plan on NOT taking the transmission out and driving it until it fails or doesnt. If it fails I will rebuild another or buy another and rebuild that too. That way I can make sure to mess it up!

 

Ordered the new seals. I ordered the kit from 4wd or some other company that sells the output seals and the shift rod seals in addition to the national one listed above. The ones in the kit are the same seals that Novak supplies in their kit. They are crown part number CROA7445. These seals have no part number stamped on them.

I decided that the best way to replace the speedo gears was to just pull the rear bearing cap, so thats what I did and never removed the seal I drove in, so I didn't have to replace them.

Yesterday I was getting some noise when coasting to a stop that sounded like a partially engaged sliding clutch gear for 4wd engagement. I cycled it into and out of 4wd and it went away. I guess the shift fork was worn too much and I should have replaced it.

I also jacked up the rear of the jeep, got under it and moved the tires to get an indication of drivetrain noise. The rear slip yoke at the transfer case has plenty of wear in the splines and I can get it to make a noise similar to the one I am experiencing.

I can't say I found the noise, but it would make sense. Then again so has everything else I have "fixed".

 

Slip yoke on the rear drive shaft?

 

Just ordered a custom driveshaft from Tom Wood. I will see if that solves my problem. My driveshaft is home made anyway, so I need a real one someday. Today is someday. He says that the noise I describe is probably due to driveshaft angle or another fault with it. Could be that the slip yoke is worn enough to cause all this? No more play in intermediate gear is maybe accentuating the problem?

 

Fixed my clatter that comes from the transfer case. I unhooked the cable and screwed the shoe adjusters in. The clatter is gone!
Yes, the clatter is from the out of round parking brake drum. As I was turning the driveshaft I could feel the high spot. As I coast to as stop it causes the parking brake drum to have a friction pulse, that may cause the mounting plate to rub on the skid plate.

Whatever, I basically unhooked the parking brake and the clatter is gone. Clunk is still there when I let off power and push in the clutch, but its not as bad and I can minimize it through driving style.

Yipeeeee!!!!!!!!!!!

 

I see a reason to go forward with the snowmobile disk brake...

 

...or a rear axle parking brake like later model CJs.

 

OK.......so that's 3 different National numbers for the output shaft seal. There must be some difference between them??? But they all work.