th350/np205 help

[meathead95]

my k20 has a new th350 in it which shifts fine no problem there but i have a transmission fluid leak and it appears to be coming out of the 2 outputs on the transfercase. the 205 runs gear oil so why is there trans fluid coming out of it? is it overflowing coming from the trans into the transfer case? is there a seal that could be causing this? i just want to know what to look for before i tear it apart

[jeffspower]

There are seals in the adapter between the trans & t-case. When they go bad, ATF runs into the t-case. Sounds like you have a little project to do!

You will also need a new gasket for the adapter to t-case. Don't use just silicone alone, or it will crack the adapter when you tighten the bolts. I'd clean the adapter up good & inspect closely. They are prone to crack anyway.

[meathead95]

i take it if it is cracked that will make it leak also? got any part numbers for the seals, as my local guys are idiots. if the adapter is cracked where can i get a new one? price? part number?

[jeffspower]

If the cracks are deep enough it can leak externally. Yep, parts store guys rarely get the right seals for a NP205. But it is tough to get them right, as there were several changes thru the years. Even sources that sell NP205 reseal kits usually don't get it right. I'd buy the gasket kit, and seals referenced to part numbers &/or dimensions of your old ones. You might have to go with a tranny shop or online source for the gasket kit. 4 wheel parts or someone on ebay usually has them. I don't know if adapters are available new, used can be hard to find (not cracked), & often go for $150+.

[Livrat]

The adapters generally crack on the top and normally will not leak trans fluid into the transfer case, but will allow 90wt to seep out.
Most of the time the ATF in the transfer case is due to either bad seals in the adapter and/or a worn coupler sleeve. I am not sure if the adapters are availible new from GM anymore, used ones usually run $100 and up. (there are two on Ebay)

Seal part numbers:

TIMKEN Part # 471869

BCA/NATIONAL Part # 471869 {Oil Seal / Nitrile / Shaft Size=1.937" Housing Bore=2.686" Outer Diameter=2.69" Width=0.375"}
New Process 205 2 Spd. Part Time Transfer Case

[hdflstf]

Just got done with the same issue with mine. PO said the adapter was cracked so I found a few on ebay, craigslist, and on this forum. After I tore it apart, I found that PO didn't know what was wrong. Turns out that the adapter was not cracked.
The problem was that one of the two seals in the adapter was cracked in about 8 places and the o-ring on the TC input shaft was cracked. I went ahead and did a complete rebuild of the TC and twin sticked it while I had it out. Take the seal P/N to NAPA as they can match up the correct seals for you, got mine in one day. The TC rebuild kit does not include those seals.

[meathead95]

wow thanks guys. is ther an easy way to tell if the sleeve is worn? i looked on ebay just a minute ago and didnt see any adapters?

[hdflstf]

Originally Posted by meathead95

wow thanks guys. is ther an easy way to tell if the sleeve is worn? i looked on ebay just a minute ago and didnt see any adapters?

There will be a shiny ring where each seal rides. If you can catch you fingernail in that spot, it's too much wear. There is enough room to make some shims to fit under the seals to move them a little so they contact a different area on the sleeve.

I need to finish up this other thread but I put a few pix up and some discussion on what I just did -->http://67-72chevytrucks.com/vboard/s...d.php?t=266278

[Livrat]

For some reason I cannot get the links for the one on Ebay to work.. so here is the Ebay item number:
180196928665

[meathead95]

link didnt work for me

[meathead95]

got it thanks, i dont know how i missed this.

[meathead95]

ok i got it apart and the big o ring on the trans side looks good as well as the 2 seals inside that ride on the sleeve. i didnt see any cracks in it either. but both seals where stiff so i removed them anyway and the sleeve does have a groove on it but not big enough to catch a fingernail so is it good or bad? the groove is on the transfer case side. how can i pressure wash this without getting water in the case or will it hurt if i do?

[hdflstf]

Originally Posted by meathead95

ok i got it apart and the big o ring on the trans side looks good as well as the 2 seals inside that ride on the sleeve. i didnt see any cracks in it either. but both seals where stiff so i removed them anyway and the sleeve does have a groove on it but not big enough to catch a fingernail so is it good or bad? the groove is on the transfer case side. how can i pressure wash this without getting water in the case or will it hurt if i do?

If you have some vernier calipers you can try to measure the groove. mine was 0.001" deep compared to the O.D. of the coupler (or 0.0005" per side). I wouldn't want to go much over that.

Pressure wash, that's part of the reason I went ahead and did the rebuild..

[meathead95]

you think if i pressure wash it and then just drain what water gets in their it will be fine? what weight oil you use in it? where can i get a new sleeve at?

[hdflstf]

Originally Posted by meathead95

you think if i pressure wash it and then just drain what water gets in their it will be fine? what weight oil you use in it? where can i get a new sleeve at?

I'm not to crazy about getting water into something with so many bearings and places to catch water. It can be hard to get it all out once it's in. 90wt gear oil is what is called for. So, the same stuff that goes in the differentials. Think I wound up using 75w90.

[meathead95]

ok thats what i planned on was 80w90 do you recall how much it holds? im just gonna clean it with a screwdriver and wire brush. how about that sleeve? do you know where i can get one

[hdflstf]

Originally Posted by meathead95

ok thats what i planned on was 80w90 do you recall how much it holds? im just gonna clean it with a screwdriver and wire brush. how about that sleeve? do you know where i can get one

Holds about 2 quarts - but I didn't measure.

Try these guys for a sleeve quad4x4.com. They may or may not be able to help.

[1969K10]

Originally Posted by jeffspower

You will also need a new gasket for the adapter to t-case. Don't use just silicone alone, or it will crack the adapter when you tighten the bolts. I'd clean the adapter up good & inspect closely. They are prone to crack anyway.

What causes this? I'm confused as to why replacing that paper gasket with silicone will cause the adapter to crack.

[hdflstf]

Originally Posted by 1969K10

What causes this? I'm confused as to why replacing that paper gasket with silicone will cause the adapter to crack.

The input shaft bearing has a snap ring which holds it in place sticking out from the case (see picture). There is a recess in the adapter that clears the bearing BUT it is not deep enough to clear the bearing if you don't install the gasket.

Another detail is that most of the bolt holes in the TC are through holes so you'll need to use some sort of thread sealer on your bolts so you won't have a bunch of leaks at each of your bolts.

[meathead95]

ok these local parts people are bigger idiots then i thought. do any of you have the part numbers for the paper gasket and o ring so i can get all the parts ordered.

[meathead95]

i went and ordered the seals bca national 471869 that livrat posted and they where clearly 1/16th larger o. d. anymore help?

[meathead95]

i went to an older napa well used by the local hot rodders and low and behold he took the national number off the seal and within 5 min he came back and told me it was an adapter seal and the brand of the new ones i ordered are nos and the part number is 19760 for whoever wants to know. it just amazes me how autozone, oreilly, and even the national website couldnt get anything off of the number on the seal but this old a$$ napa did.