Crossmember and TC adapter identification

[dremu]

More "name these parts", except this time, I *don't* know what they are or came off of.

As usual, "Bob" isn't good enough

First one is this tranny/t-case adapter, on a crossmember.

I would guess it's a TH350-NP203 adapter, and a cross-member for a 73-80 frame, but I'd be happily corrected.

Second is this other crossmember ... different, from an 81+ frame? Other?

Any spotter's guides for ID'ing these sorts of things or tips as to why these are what they, much appreciated. I'm starting my Doubler project and gotta figure out what to use.

-- A

 

[thatK30guy]

Top 2 pics are the 350/203 adaptor on a K5, 10 or 20 crossmember of the second design.

Bottom pic is the first design crossmember which is '76 and older.

Forgot to mention the top pics of the crossmember are '80 and older. '81 and newer members look a little different.

 

[dremu]

Top 2 pics are the 350/203 adaptor on a K5, 10 or 20 crossmember of the second design.

Bottom pic is the first design crossmember which is '76 and older.

Forgot to mention the top pics of the crossmember are '80 and older. '81 and newer members look a little different.

So they'll both fit on a '74 frame?

-- A

 

[thatK30guy]

Yep, but beware that not all crossmembers share identical hole patterns. Drilling out to ream the holes out on either the crossmember or frame may or may not be necessary.

I also forgot to mention about the bottom pic crossmember that on those types, the t-cases usually had that "L" shaped bracket that bolted to the side of the case to the inside frame rail. Newer ones had that longer strut rod that bolted to the bellhousing on the tranny.

 

[dremu]

Yep, but beware that not all crossmembers share identical hole patterns. Drilling out to ream the holes out on either the crossmember or frame may or may not be necessary.

I also forgot to mention about the bottom pic crossmember that on those types, the t-cases usually had that "L" shaped bracket that bolted to the side of the case to the inside frame rail. Newer ones had that longer strut rod that bolted to the bellhousing on the tranny.

I'll be doing a doubler, so drilling is to be expected.

Thanks for the scoop on the second x-member; it was confusing me.

Next I gotta tear into the truck and see what's in there ... this is just my spares pile

-- A

 

[CyberSniper]

The adapter in the first two pictures is a TH350/203 adapter. The crossmember is 79 or older. I know my 79, 80, 81, 82, 83, and 84 flat crossmembers all have the dent in them for a CV driveshaft. That one appears to have no dent in it for a CV driveshaft.

I don't know what year that lower crossmember is. My 73K20 had a 4 piece crossmember.


If you're going to be using these things for a doubler setup like you mentioned, you might want to try to get a ~79-84 crossmember out of a 1 ton. They are even flatter because the frame is taller.

 

[thatK30guy]

If you're going to be using these things for a doubler setup like you mentioned, you might want to try to get a ~79-84 crossmember out of a 1 ton. They are even flatter because the frame is taller.

I wouldn't recommend using a flatter 1 ton crossmember as it will put the tranny/t-case combo up higher in the frame rail. It may even hit the bottom of the floor board if there is no body lift.

The '81 and newer crossmembers look different than what the pictures show. I have one in the garage but no camera yet to take a pic. The top two pics are definitely '80 and older.

1 ton frames are not "taller". They are "wider" vertically going downward rather than upward. This does not give them more lift than a non-K30 truck.

 

[CyberSniper]

I wouldn't recommend using a flatter 1 ton crossmember as it will put the tranny/t-case combo up higher in the frame rail. It may even hit the bottom of the floor board if there is no body lift.

As far as I know, he wants to use them for a doubler. You can push the transfer case a solid inch up and still have plenty of room on a stock pickup (I've done this). The only thing that hangs below the frame on my rig is the crossmember and adapter... the transfer case and transmission are above the bottom of the framerail.

The '81 and newer crossmembers look different than what the pictures show. I have one in the garage but no camera yet to take a pic. The top two pics are definitely '80 and older.

The only difference between my 79 crossmember and my 84 crossmember are the locating holes for the transfer case adapter, the 84 is full of "lightening" holes, and the 79 has different holes in it for the skidplate.

1 ton frames are not "taller". They are "wider" vertically going downward rather than upward. This does not give them more lift than a non-K30 truck.

They're "taller" in the sense that the C-channel is around two inches "taller" from the rear spring hanger to the front shackle hanger. Since the frame can't magically go into the floor it must've gone down... since it went down... and the motor stayed in the same location... the crossmember got "shorter". We're on the same page but I don't think I made it clear what I was saying.

 

[dyeager535]

Wes posted this awhile back, just for clarification purposes I'm bringing it back:

"While John is correct on the '84 and older 1 ton flat members being shorter than the 1/2 and 3/4 tons, the '85 to '91 crossmembers are all the same between 1/2, 3/4 and 1 ton.
Even though the 1 ton uses a shorter crossmember, these '85 to '91 has the crossmember sitting on TOP of the lower frame rail rather than under the very bottom part of the rails like all the other non-1 tons do."