Dana 20

I am rebuilding my Dana 20, there are of course end play adjustments that need to be made on the front and rear output shafts. Nowhere online can I find that any of the rebuild kit instructions offered by various kit sellers do they mention the gasket placement for the shim pack and bearing retainer (front output shaft). With that being said if you are using a gasket and striving for a .002 to .005 end play you would have to include the gasket in part of your calculation and or trial pack? For the rear output shaft it looks like you would have to pull the bearing again each time you check for correct end play there?

 

I rebuilt my Dana 20 last spring. I used the Novak kit. The reviews were great, but I thought the directions were lacking in some parts. I found this article Rebuild Your Dana 20 at Home - FOUR WHEELER NETWORK plus the Novak guide to be a pretty good step-by-step. The end play clearance setting is “fun”. I made great use of a battery operated impact M18 FUEL™ 1/2" Mid-Torque Impact Wrench with Friction Ring (Tool Only) and a relatively cheap (but not the cheapest) magnetic stand dial indicator. It was all trial and error for me. It took me about 5 tries to get the rear output end play set correctly. Per the instructions (if i’m remembering correctly) you set the end play before installing the seal. It wasn’t too difficult, but it was a learning experience for me. This spring will be a T15 rebuild for my ‘72. I’ll probably start thread when I start and be asking for help as needed like you are. I’ve been watching your questions and all the replies across a few threads - please consider starting a build thread so we can see your progress. I know I find it encouraging to see others struggling and overcoming their obstacles. Keep at it!

 

Thank you, rebuilt my t-15 already, no help with that, instructions were lacking, couldn't even find the correct diagram but I got it done, pretty simple.

 

There is no gasket included in the shim pack. The factory cases were assembled then painted as I recall, and the paint may have served as something of a sealant on the outside of the pack. I tried smearing sealant on the outside edge of the pack, and that seemed to work. Some here put spray-on gasket (Copper-Coat?) on the shims and seal them that way. If you search through old posts you will find lots of discussion about sealing the 18 and the 20 - techniques should be similar for both. IIRC there's just a paper gasket between the output housing and the case, and no adjustment in that dimension. The TSM should cover assembly pretty well.

 

That’s what I do, and that’s one spot I never have leakage issues.

 

Permatex high tach may do the trick then, there was a gasket on mine, perhaps it had been removed at one point and someone placed one of their own, it was a bugger to get it off, not sure if it was original

 

If there was a gasket where the shim pack goes someone added it. No gasket there through the 18/20/300 transfer case series. I’ve seen shellac on the 300 transfer case shims and sometimes on real late model 20’s (from the factory) but that’s it. I use Permatex RTV Ultrablack between the shims. Super thin coat. Never had a leak from there and never had it change endplay/preload. Make sure you use some sealer on the bolt threads as well. As usual proper prep is key.
I tried high tack and other products and found them a pain in the arse to get that stuff off down the road if needed. To the point I’ve thrown away the shims and started over.

 

I have approx .164 for shims on my end plate, is that normal, feel I have about more than double what I had before I tore it apart, bearings are correct, pressed on till they bottom. Just left with a great deal of space between plate and transfer case?

 

To get close I put forward pressure on the front output shaft using the cover plate from the rear then use feeler gauges between the plate and the case. That gets me close then I fine tune from there. Make sure the front output yoke is on and THE NUT IS TORQUED PROPERLY. This makes a huge difference.

 

I have not put the yoke on. That will change end play? Mine has a spacer that’s goes on the output shaft before the yoke, that may make the difference? It shows adjusting the end play with the yoke off?

 

It’s the output shaft spacer.

 

It can effect it. Tightening the yoke on and torqueing the nut properly pulls all the components together properly. If you don’t do this you may run into stacking clearances that will make it impossible to set the bearings properly. This was a mistake I made when I first started rebuilding 18’s, 20’s, 300’s, 205’s, etc. After fighting the problem and figuring out what was going on I never made that mistake again and haven’t had a problems since. yes, make sure the spacer and all other components are installed correctly. Just as if it was final assembly.

 

Thanks for your help, I appreciate it!

 

So dumb question here, rear output shaft end play adjustment, how can adjustments be made without pulling the front bearing, nut and yoke and starting over?

 

Rear output endplay is made with shims between the speedometer drive gear and outer bearing. You must remove the rear output yoke, outer bearing to change endplay/preload. I do this with the rear output unit out of the transfer case in a press to set it before final assembly. I also do it without the rear output seal installed so it isn’t damaged potentially causing a leak.

 

One other thing, I do all my endplay/preload setups without the yoke seal installed so I have a better feel for what is going on. The tightness of the seal can mask how tight things are. I set my outputs, remove the yoke, install the seal and seal up splines and thread lock the retaining nuts. NEVER had a failure doing it this way. 25ish years don’t lie. Just what has worked for me. Ymmv.