Dana 18 Rebuild Question: output shaft endplay

I've been following the Willystech.com rebuild guide; I am at step A20 (setting endplay).(http://web.archive.org/web/20120112....com/wt/Model18TCase/Model18TransferCase.html).

It appears that on my first attempt I've made things too tight (gears were hard to turn). I wasn't thinking to check for endplay as I was tightening the caps, so I don't know how off it is, but even a slight loosening of caps allows the gears to turn freely yet still no endplay that I can feel. I was using the original shims.

I read to give things a tap and ensure that the bearings are sitting correctly and that didn't seem to do anything, but not sure if I did it correctly. Is it a sideways, along the axis, or both type of tap, and how hard?

I also read some other threads that suggest making sure the front cap has its gasket on and that the speedo drive gear is on. To do that I'd need to push both bearing cups out slightly and try again. What's the proper way to do this without messing up the bearings: do I just take off the caps and tap each end of the shaft?

 

Thanks!

Ok, I redid things (this time with old front gasket, speedo gear, and repeatedly checking play and seating as I tightened) and now have .003". If I read the howto correctly, then after I add sealant and the new front gasket that should get me within the .004-.008" spec.

 

What Howard said. I use RTV ultra black but the excess squishes out (apply super thin coat). Also put sealer on the splines of the yokes to keep leaks from happening down the output shaft splines. Everything needs torqued to spec before checking end play. Make sure you check endplay with the gaskets installed you intend on using as that can change things.


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Thanks fellas. Got the end play to .004".

I have another question/concern. I'm wondering if my output and intermediate gears are somehow too close. As I started to drive in the intermediate shaft the gears stopped moving freely. In fact, right now with 3/8" left of the intermediate shaft to push in, I can't spin them with my hands. Also, I couldn't shift the sliding gear into low (granted I don't have the stick on for leverage). Is this typical and should correct itself after a few rotations by the engine or am I somehow binding the gears?

 

Hmm. Talked to Herm and he said that if I had the endplay correct, then the rest (extreme drag from intermediate shaft) should work itself out.

 

I don't recall anything binding up when I put mine together once the shaft was started into the front side of the case. Did you use assembly lube on the needle bearings?

 

The gears should not bind. Everything should turn freely with a slight drag being normal. Check for burrs on the gears or foreign material. If you install it and just let it work itself out you will be doing this again when the metal particles or foreign material, or whatever is causing the drag runs through your new bearings.


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I don't have assembly lube, but I used vaseline on the needle bearings.

I'm going to check endplay more. Maybe see how the gears mesh with a loose endplay to be able to make a comparison.

 

The output shaft endplay will not effect the mesh of those gears with the intermediate gear unless endplay is so loose it's compensating for another issue. If the problem happens when the intermediate gear is installed then it has to be a mesh issue between the intermediate and the other gears or with the intermediate itself (thrust washers, bearings, shaft, etc). Is it possible the intermediate shaft retainer bolt is too long pushing on the thrust washer causing it to be tight against the gear? I've seen this happen.


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Anything that I might have done to cause those gears to be too close together?

Retainer bolt is not in yet, the shaft is still sticking 3/8" out bc I didn't want to force anything with the gears acting how they were.

 

So I loosened both bearing cups and the output and intermediate gears spun again, easily by hand. However, I could see that the front bearing was off center, being pushed away from the intermediate. This correpsonds to how hard driving the intermediate shaft in was until I put the sliding gear into neutral (took the sideways pressure off).

When I put the front cap back on and very loosely snugged the bolts, the gears stop being spin-able. I put the yoke on the rear splines for more leverage and still no turning.

 

For a sanity check I installed the original gearset and the drag was as expected (exists but gears turn-able). I suspect that this means that I installed the new gears correctly but I have a case-gearset mismatch (case is Mitsu, new gears are Dana). Herm originally said that the case and gears should be compatible, but looks like we can't win them all, as these are not.

To finish the rebuild & overdrive install I believe that I have 2 options:
-find a US 1-1/4" case to match the gearset Herm sent, rebuild it and use the OD Herm sent
-use my original case and original gears but return the OD for a bowl gear that matches

 

Herm says that he's unwilling to do the 30 t OD bowl gear option.

So I'm looking for cases, tons of Dana 20s around locally, but not any 1-1/4 intermediate Dana 18s yet. Has anyone seen a spacer or press-in sleeve of sorts to allow Dana 20 or large bore Dana 18 cases to work as small bores? All I could find were transmission specific adapters that seemed to require changing the tail shaft.

I also contacted a local 4 wheel shop that has a fellow that likes working on older CJs. I may take my mitsu case and us gears to him. Best case is that he gets it to work and problem is solved, worse case I know for certain the case & gears are incompatible and I'm not crazy here. Tomorrow may involve me and a micrometer comparing the gears before then though.

 

Put a wtb ad in the classifieds or call R&P at 503-557-8911. There should be a small hole 1 1/4" intermediate case floating around. That's what the Willys pu's and Wagons used so should be plenty around.


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