leaking T-90 and dana 18

I have been rebuilding a 61 cj5 with a f-head 134 and a t-90 and dana18
the transmission and tranny work great other than the fact that they leak like ther is no tomorrow, so i bought gasket and seal sets for both the transmission and transfer case and now have them puuled out of the jeep. my question is, is there anything special that i need to know before i pull the transmission and transfer apart, is there supossed to be a gasket or any silicone in between the two? Or do they bolt up flush with each other metal to metal. Is anything going to happen or fall apart when i start to pull the different covers and plates off so that i can put the new gaskets in? I think that they have been pulled before because there is orange silicone around the transmission and transfer mating surface, will anything happen when i pull the two apart?
thanks

 

Hello bjames, welcome from NC.

You asked if there is anything to know when pulling the T-90 & dana18 apart, and the answer is YES. The biggie is to make sure that tranny gear bearing rollers don't drop into the bottom of the case when separating the 2 cases. Have you had those apart as of yet?

Not being an F-134 guru (V6 guy here), I'll venture a guess that the tranny and D-18 definitely require a fresh gasket instead of iron-on-iron. If you get a gasket set (available at 4wd hardware and others), consider applying a thin brush of hi-tack sealant on each side of each gasket/shim pack, as well as on the threads of each (cleaned) bolt affixing the 2.

Piece of cake, right?
-Alan

 

As said above, be carefull not to allow thge trans output shaft to pull out of the casing. An easy way to avoid this is to remove the cover plate on the back of the transfercase and yse your hand to guide the bull gear out through the opening. You need a gasaket between the two boxes. You can make one out of thin gasket material and a ball peen hammer. Simply place the gasket material over the surface and begin tapping around the edges with the round end of the hammer. This will cut the gasket in the perfect shape. It even works on the bolt holes. This trick works on virtually any gasket job, and can save some time if you need to order the replacement.

 

thanks for the info on the gasket, that will be very easy to make. what about this trans output shaft could anyone go into a little bit more detail in what i need to do to make sure it doesn't drop, what is the bull gear? i took one bottom plate cove off the transfer case which measured 9-10 inches long by 4-5 inches wide and inside is a lot gears that are next to each other in a row, is this the bull gear?
you guys are a big help thank you

 

Here's how I keep the tranny together when seperating it from the TC. I take the top cover off the trannny and fish a piece of bailing wire under the main shaft and behind the main gear at the rear of the shaft. I then run the two ends of the wire through the front holes in the top of the tranny where the top cover bolts on. I get this wire as tight as practical, but it doesn't need to be real tight. Just enough to limit the rearward movement of the shaft. As I recall, back and forth movement of the shaft of about 1/4" is fine.

The main shaft rides in a bearing that sits in the back of the tranny case. This is the shaft you will see when you remove the upper inspection plate on the TC. The TC assembly is what holds that bearing in the back of the tranny. So by wiring the shaft as I described in the first paragraph, you keep the bearing from backing out of the tranny when you slide the TC case off the shaft.

I seem to recall noticing that there was no gasket between the two the first time I pulled them apart. But the gasket set I bought from Walcks had a gasket for this, or you can make one as described in a previous response.

Clear as mud? Let me know if any of this is confusing and I'll try and clarify. Good luck with the project. I'm still waiting for the magical solution to the leaking T90. I have replaced the seals and gaskets twice in mine and it still leaks.

 

Double lipped Nation Seal number 450185 and silicone on the splines before you put the yokes on. Mine stays fairly dry.

 

I just did a D18 rebuild last weekend, and know exactly what you are going through. I don't have the same transmission, but I suspect the rest was similar. Novak recommends RTV Gray silicone for the seals, if that helps. There are several kits available, with a variety of pricing. Be careful about the quality of the intermediate shaft if you decide to replace it (which you probably should, I'm guessing). Anyway, that's my 2 cents.