Dana 18 Leak Troubles

Normally there is a seal in the adapter plate that the spacer between the mainshaft bearing and transfer case input gear seals against. It's just a larger bore the seal presses into. Never seen one that didn't have a seal there including the T-98's, but there's always an oddball out there.

 

Have you checked your transmission shifter rail plugs. My T86 was leaking a ton of oil and it ran down the front of the transfer case. It made it look like the intermedaite shaft was leaking.
Clean the entire thing with brake cleaner, pull the transmission cover and pinpoint the leak.

If it really is coming from the e-brake, and since you replaced the seal it may be that a grove is worn in the yoke. Replace the yoke or use a speedysleeve to clean up the groove. Dont forget to put sealant under the speedysleeve.

Also, if there are shims at the back of your transfer they might be allowing some leaking. You can remove the ebrake backing plate and speedo gear housing and clean the shims, spray LIGHTLY with sealer like napa copper then re-install everything putting thread sealant on the bolt threads. Be careful with those shims because they set the endplay of the d18. And only go very lightly on the sealant because it will ad up to a few thousandths of additional clearance.

It sounds like you have so much leaking that something reasonably big isn't right.
Fix that before looking at little drips.
Tom

 

I checked the rails and they appear/feel dry.

I did all of the stuff in the quote above the last time I had it apart a year ago.

Gonna share my ignorance - what's a speedysleeve?

 

a speedi sleeve or redi sleeve is a rediculously expensive thin metal wrap that can go over the yoke and give it a new, even sealing surface.
http://www.alliedbearings.com/mfg_prod/seals/cr_speedi/index.html

When you pull the yoke you might be able to feel if there is a groove where the seal rides. So thats the signal that your seal might not be able to...seal.
Some of the army jeep vendors were selling new surplus yokes cheaper than a sleeve a couple of years back so shop around if you find thats where your leak is coming from.
Tom

 

I recall that the output yokes can be double sealed? The newer design seals are thinner, or else you can remove the felt packing behind the original seal and run two rubber seals? Something like that. this would be covered in old posts. There have been a lot of posts about sealing the D18 ... a perennial problem.

If you go with a double seal, you might give the seal area a good polish with some crocus cloth. The region for the new seal may be slightly pitted after 50-60 years on the road.

 

Ok, on this oil sharing thing between the D18 and the transmission, what about between the D18 and a SM420 using an Advance Adapters kit? The main input bearing for the D18 is a double sealed bearing and I also noticed on mine that the spud shaft is rusted, but there is no moisture or water in the SM420, the OD or the D18. Should oil be shared in this situation between the D18 and the Sm420?

 

Thanks all - this is very helpful and is something I had not considered. I'm on new turf here.

 

depending on how bad the groove is, you may be able to get the yoke resurfaced and use an undersized seal.

 

My HEEP has sat parked in the driveway for a week now without being driven. This morning I go out and sometime during the night last night she randomly decided to pee what I'm guessing to be about a half quart of 90wt onto the driveway. Crawled underneath and I can see a trail running out the back of the intermediate shaft and down the case. Going to give Patricks RTV trick a try. Not sure what caused it to randomly start leaking when it hasn't even been started.

 

I chased a leak for a long time. Replaced seals, installed a redi-sleeve, RTV'd the yokes. Nothing worked. I finally did a real close look and found that the metal covers over the shift rails on the t-case had pin holes in them from rust. I talked to Herm about this and he said he has seen it before. I cleaned it up good and put some of Billy May's Miricle putty on them. Been dry ever since. JB Weld would probably work also.