TH400 to 208 transfer case Adapters

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1987_chevy_

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OK so you probably have the right crossmember then. You're confusing us when you say adapter. The adapter is what goes between the transmission and transfer case. I'm not aware of any adapter for the crossmember to the Tcase adapter. Are you maybe talking about the transfer case mount? There is a mount that goes between the crossmember to the transfer case adapter. Probably adds maybe 2 to 2.5 inches.
As in adapte, the piece that allows the th400 to connect to the np208. The picture of my tranny. The tranny shop put the wrong one on my tranny and the transfer case does not bolt up correctly to the tranny. So I have to order a new one.

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1987_chevy_

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You say your transmission is already bolted to the transfer case, so you've already got the adapter. Now you just need the correct crossmember and rubber mount. Does your Th400 and NP208 look like the one I posted above in the tractor bucket? If so, then you have the correct crossmember and you just need the rubber mount. Should be a very common part.
The adapter The tranny shop gave me is the wrong adapter, the transfer case does not sit right on it. I already have the correct crossmember
 

HotRodPC

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Yep, I agree, that adapter don't look right. Maybe an aftermarket? The transfer case adapter you're looking for to use that wavey crossmember will look like this one.


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You say you had a 700r4/NP208 before with the wavey crossmember? If you find the correct OEM GM adpater that was used on our trucks, the length will be the same and you won't have to cut your driveshafts, so keep that in mind when looking for an adapter. If it's cost $30 more or something like that, it can save you a few hundred in driveshaft modifications.
 

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As in adapte, the piece that allows the th400 to connect to the np208. The picture of my tranny. The tranny shop put the wrong one on my tranny and the transfer case does not bolt up correctly to the tranny. So I have to order a new one.

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Looking at what I can see of the adapter since it's the front of the transmission instead of the rear, it looks like a longer adapter. Makes me wonder if they didn't use a 2wd Th400 output shaft so they had to use a longer adapter. That's all fine, but it'll require cutting your driveshafts to make them work since the distance is going to be different. I think we need more info to be able to help you out.
 

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Yes that is the cross member I used with the short adapter, but here is the thing the mount is pretty tall which probably makes it the same size as the tall adapter.
 

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Yes that is the cross member I used with the short adapter, but here is the thing the mount is pretty tall which probably makes it the same size as the tall adapter.
Right !!! But I think his biggest issue is the length of transfer case adapter. That one is NOT OEM to our trucks. They might have used a longer output shaft like you did, unless he gets the right output shaft and right adapter. A pic of the side rear of the transmission would be helpful so we can see it.
 

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Right !!! But I think his biggest issue is the length of transfer case adapter. That one is NOT OEM to our trucks. They might have used a longer output shaft like you did, unless he gets the right output shaft and right adapter. A pic of the side rear of the transmission would be helpful so we can see it.
Maybe he should look at my I need a spacer thread.
 

1987_chevy_

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Right !!! But I think his biggest issue is the length of transfer case adapter. That one is NOT OEM to our trucks. They might have used a longer output shaft like you did, unless he gets the right output shaft and right adapter. A pic of the side rear of the transmission would be helpful so we can see it.
Right !!! But I think his biggest issue is the length of transfer case adapter. That one is NOT OEM to our trucks. They might have used a longer output shaft like you did, unless he gets the right output shaft and right adapter. A pic of the side rear of the transmission would be helpful so we can see it.

I'm not able to get a pic of the back of the tranny, the whole truck is in a shop being worked on! If everyone says the short adapter will work with the wavey crossmemeber I should be good
 

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I'm not able to get a pic of the back of the tranny, the whole truck is in a shop being worked on! If everyone says the short adapter will work with the wavey crossmemeber I should be good
I'm running the one you've posted and the short adapter.
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1987_chevy_

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Yep, I agree, that adapter don't look right. Maybe an aftermarket? The transfer case adapter you're looking for to use that wavey crossmember will look like this one.


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Did you have to modify the transfer case support that runs from the transfer case to the front of the tranny (the metal rod support) that is in the picture you posted?
 

Honky Kong jr

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Did you have to modify the transfer case support that runs from the transfer case to the front of the tranny (the metal rod support) that is in the picture you posted?
Your stock 700r4 one should work. I made my own it's bolted to the frame but my engine and trans is solid mounted.
 

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Looking at what I can see of the adapter since it's the front of the transmission instead of the rear, it looks like a longer adapter. Makes me wonder if they didn't use a 2wd Th400 output shaft so they had to use a longer adapter. That's all fine, but it'll require cutting your driveshafts to make them work since the distance is going to be different. I think we need more info to be able to help you out.


You are probably right about the output shaft. They would have had to swap out the original shaft because it was way way to short, the 2wd shaft was probably laying in their shop somewhere just waiting to be used. There's a few different lengths though, so the adapter reasoning is hard to say.
 

1987_chevy_

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Ordered it! Thanks for the help everyone!

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