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739 Views 7 Replies 4 Participants Last post by  89cummins
is there a gasket between the t-case and the transmission? on 89 w250 auto
or if there is could rtv sealer be used?

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I used to make my own out of gasket paper. When I was a kid I used to have a granny and a 205 case. Back then the gasket for the chevy was 50 or 60 bucks. Took a ball peen hammer and made my own.
What I like to do is use the old gasket and rtv. Ideally the gasket sticks to one side or the other. I clean the side that separated with aerosol brake cleaner, let that dry then use the rtv. If it separated on both sides in some places or tore I do the same thing with both sides and reuse it. RTV is great stuff, but to really work well it needs to be clean and oil free. If you're not going to reuse the gasket I would probably use an anaerobic(sp?) flange sealer. Same thing, 2 sides clean and oil free.
Steve g
thanks for the info
mine was leaking pretty bad last month and i just slid the t case back a tad bit bout an inch and a half. i had enough room to work adn i pulled the old gasket out wrapped a shop towel in there wiped all oil off teh flanges. adn just used a heavy coat of rtv tightened the case back up adn has not leaked one bit since then. only took bout an hour. but i had to drop bot drive shafts.
my gasket was gone.:lol3: don't think thats good. But i have to get my t-case in by wednes afternoon and i only have tues and wednes to do it. If i can't find a gasket quick enough could rtv sealer hold it for a while if the surface area is clean?
Yes, it'll be fine. I would use lacquer thinner or brake cleaner to make sure it's clean tho. Wiping it off with a rag or using solvent will leave an oil residue behind that will not allow as good a seal. In the absence of thinner or brake cleaner you could wipe it down with clean solvent then rub it down with hot soapy (Dawn works well) cloth to remove the oil. It may sound like overkill, but I've seen tons of leaking flanges that simply weren't cleaned well. Also, make sure your bead of sealer is between the bolt holes and the inner edge of the joint, not the outer or it will leak through the bolt holes. It may seem obvious, but I had to split a big AGCO Allis tractor between the trans and diff recently because the previous mech went around the holes just like that. Huge job for a little mistake.
Steve g
I have another question, could you mix different tranny fluid brands as long as they are the same type (dextron III)? and what should i use for t-case fluid? Thanks
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