Dana 18 problems

Had D18 rebuilt. after several hundred miles it develoved a growl, but only on a down hill grade at 45 mph or faster. figured out it had alot of endplay in the output shaft to the rear. suspected that maybe one of the bearing races had not been seated properly and moved. sent it back to the guy who rebuilt it. he took it apart, said it looked OK reset endplay and stuck it back in. Ran it awhile, growl came back, same problem. seemed to have alot more shims under the bearing retainer,than normal. took a few out to tighten it back up. was good for awhile, now it's growlin again.
this is actually on my cousins jeep, I rebuilt mine and my dads myself and had no problems, seemed pretty straight foreward, so why does this thing keep ending up with a bunch of end play.

 

The intermediate shaft is usually suspect on the D18. I understand that many of the brand new ones are cheap off shore junk so it's possible it's bad. Best to use a known good brand - Novak.

I don't see how the end play could change in a short period of time?

Call Herm.

 

using a nylock nut or a castle nut ?
is it staying tight ?
torqued properly ?

 

Why would you replace the 'mediate shaft anyway? It's not a seal right?

 

by design, the intermediate shaft is a source of most of the noise/highway whine on a D18 transfer case. Usually replacing the intermediate shaft and the bearings will quiet it up some. Replacing the gear, shaft and bearings is no guarantee it will be quiet, FYI. There will always be some whine out of the unit. It's called an offset transfer case; the power comes into the unit on the drivers side; output is on the pass side; thsi transfer of power thru the intermediate gear puts angled pressure on the gear,shaft, and bearings.

 

Nuts are staying tight, not sure what intermediate shaft they used. But the end play in the ouput shaft is the issue. As I recall, the front and rear output shafts fit together (one slips inside the other) could they wear at that contact point or is there a thrust washer that could be self destructing and opening up the end play???

 

something obviously not right....
with the bearings ?

 

I thought earlier today that "NO" thrust washer (upon rebuild) might account for the slop ...

 

I had a growl in my t-case that was worse when decelerating. It turned out to be a worn intermediate shaft. I replaced the shaft with one that was "Made In the USA" about 5k miles ago and it fixed the problem. I regularly travel at 65 to 70 mph with no noise. So...my bet is that the problem is in the intermediate shaft and has little to do with the end play on the rear output shaft, as you described. However, that kind of play in your output shaft does worry me; particularly since without some preload on the bearings they can wear incorrectly and start to make a noise. I would suggest dropping the inspection plate, drive out the intermediate shaft (be careful because either caged needle bearings or non-caged bearings with some spacers will drop out with the gear assembly), and take a look at the bearing surface on the outside of the shaft. You will likely see that it is wearing to be oval shaped rather then round. I believe that when not under load, the bearings wobble on the ovalled shaft and make the growl. When under load, the gear shifts on the shaft and forces the bearings to stack up on the ovalled shaft and make no noise.

Ovalled, stacked up, and wobble aren't technical terms, but it is all I got at this hour. Good luck. And if you run into difficulties, I believe Novak has a description of how to replace the intermediate shaft on their web page.