NP208 and TH400 Question!!

[Jukes14]

Going to mate my NP208 transfer case up to my TH400. My question is, where they bolt up together, is it a dry connection? Or should I put some black RTV in-between where they meet up? I've attached 2 photo's to help you guys understand what it is that I am asking! Really appreciate the help!


Cheers

 

[Jukes14]

Any help / insight?

 

[1987 GMC Jimmy]

It's a dry connection. The transmission output seal and the t-case input seal are supposed to cover you from fluid leaks. I think there is a little paper gasket that you can buy, though, that goes in between the two... Yes, there is. I searched "NP208 to TH400 gasket" and found several options for sale.

 

[Honky Kong jr]

There should be a paper gasket on either side of the adapter. The input shaft seal on the transfer case prohibits fluid transfer.

 

[Jukes14]

Thanks for the help!


Also, off the top of anybody's head. TH400 transmission mount. Bought a new mount a while back, never came with the nuts or lock nuts for the 2 threads. Does anyone by chance know what the required lock nuts are for the transmission mount?

 

[Honky Kong jr]

I wouldn't use nyloc nuts due to heat

 

[Jukes14]

I wouldn't use nyloc nuts due to heat

You would just suggest one normal nut? Or two of them together to stop them from coming off?

 

[Honky Kong jr]

I used all steel grade 8 lock nuts the kind that the ends look crushed. If that makes sense. It escapes me right now their proper name

 

[Jukes14]

I used all steel grade 8 lock nuts the kind that the ends look crushed. If that makes sense. It escapes me right now their proper name

Thank you Kong! I know exactly what you mean now! I've had one heck of a day today.. cloudy head, I could think of it for the life of me! Greatly appreciated

 

[Jukes14]

I also got an email back from Chris at ORD (Offroad Design) that gave some good insight to perhaps anyone else that could benefit from his response!

This pertains to mating a TH400 transmission to a NP208 transfer case. And regarding the seals / gaskets for the adapter after the tailstock on the tranny, and after the adapter to the face of the transfer case.

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From Chris: "Gaskets aren't critical there, you can use them if you want but you don't have to. There are some applications that absolutely NEED to have the gaskets there (such as NP205's and some older 4 speed manual transmissions, etc.) But this (TH400 to NP208) isn't one of them.

- Chris Holick
Engineer, Research and Development

ORD

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I hope this information will help some others out!

 

[Honky Kong jr]

I find that amusing because the factory put gaskets there. And trans fluid lays in the tail housing and with out a gasket it will find its way out. Do what you want I will keep gaskets in there or the square o ring.

 

[Arkansas_V8]

Hate to raise the dead.

But I am having trouble finding the paper adapter gaskets.

Got the transmission output seal and the transfercase input seal.

I am still leaking pretty decent from what appears to be the adapter area.

All started from a bolt missing on the tranny mount causing it to flex. Sure I ate those two seals.

I would hate to tear into it without everything I need with me.

 

[Termite_Delight]

I'm sure you could make a gasket to suit.

 

[bucket]

https://www.amazon.com/4L60E-TH700-...t=&hvlocphy=9018164&hvtargid=pla-839532713171