NP208 Transfer Case knowledge base

[Recovry4x4]

Greetings folks, in my quest for an NV4500, I now have a Dodge NP208. It should bolt to the back of the NV but there's a problem. It not only has the 6 bolts, it has a registering dowel too. The trans isn't drilled for that. None of my GM 208 transfer cases have that nor does the Dodge NP241. Anyone see an issue removing the dowel?

 

[gringeltaube]

I would just remove that pin and assemble without it.

 

[ken]

Removing this pin may present a problem. Because, It was used to keep the input shaft in parallel alignment with the tranny output shaft. For example, most bolt holes have about .015 inch clearance. That doesen't seem like much but to a machinist that's about a mile. So lets say that gives us .007 per side of movement. If you are off to one side this much, you are going to plow/ side load your bearings. If they are not deep groove bearings they are going to be upset with you. Also if there is any bushings, the shaft riding in them will be metal to metal on the one side. Also the lips seals will be side loaded and wear quicker. Giving you the Humvee vampire effect. Now you could get lucky and get everything in alignment when you go together. Do you know how much clearance you have between the adaptor bore and the boss on the tcase? If it's within .002 that would get you close enough to run it.

 

[steelsoldiers]

I would pull the dowel given the fact that the GM versions did just fine without it.

 

[Recovry4x4]

Removing this pin may present a problem. Because, It was used to keep the input shaft in parallel alignment with the tranny output shaft. For example, most bolt holes have about .015 inch clearance. That doesen't seem like much but to a machinist that's about a mile. So lets say that gives us .007 per side of movement. If you are off to one side this much, you are going to plow/ side load your bearings. If they are not deep groove bearings they are going to be upset with you. Also if there is any bushings, the shaft riding in them will be metal to metal on the one side. Also the lips seals will be side loaded and wear quicker. Giving you the Humvee vampire effect. Now you could get lucky and get everything in alignment when you go together. Do you know how much clearance you have between the adaptor bore and the boss on the tcase? If it's within .002 that would get you close enough to run it.

I need to measure the bore of the trans and snout of the case. I know my GM stuff is a close tolerance fit. I will compare these and see. I know the 208 and 241 swap and this trans had the 241 so I'm hopeful.

 

[gringeltaube]

Removing this pin may present a problem. Because, It was used to keep the input shaft in parallel alignment with the tranny output shaft.....

... with just one pin?

I guess it's the boss on its front face that should keep everything aligned. Measuring about Ø124.4mm (4.897"), while the bore in the adapter is Ø124.5mm (4.900").
Close enough.

 

[nyoffroad]

That dowel pin would be gone so fast....

 

[wheelspinner]

It only exists for ease of manufacturing. Nothing else.

 

[Recovry4x4]

I would like to say thanks to everyones feedback on this issue. I shall remove the dowel and go forth. The install won't be until spring, I'll report the results then.

 

[Recovry4x4]

So, I was researching last night and stumbled on this thread at Ramcharger Central. https://ramchargercentral.com/vehicle-help/nv4500-to-np208-issue/
I immediately went looking for pics of a 241 to compare. I've attached both. Feeling slightly defeated, I went out today to fiddle with it.

Was able to remove the dowel and tried a test fit despite the fact that the link said it was a no go. We slid in on and missed by about .155". There is a seal in there that may be an obstruction . Going to pull the tailhousing off and test fit that way. Either way, it looks very workable. I'll try to get pics in order.

Edit, that didn't work, pics are in reverse order.