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Crossmember for a 1 ton

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millernerds

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I have a 1980 Chevy 1 ton 3+3 truck 4x4, has sm465 tranny and a np205, both have the 32 spline and round 6 bolt pattern, tranny is out of an 1982 burb and the t-case is out of 1985 truck, I've been trying to locate a crossmember for this but to yet no avail, I got one off Ebay but I think it is for a np203 since the bolt pattern didnt line up to the adapter and it was a little lower than what I thought it should be, so my question is, from looking at the truck, i'm looking for a crossmember that is high on the drivers side and lower on the pass side, does this make sense to anyone? and if so does anyone have one? or where can I find one? I've been told by the junkyards that it has to be out of a 1 ton and be 85 or newer??? Thanks for any info.
Shawn
 
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I'm 99% certain it doesn't matter 1 ton or 1/2ton. I've got the crossmember you are talking about in my truck, it came out of a 1/2 ton, and I'm using it with the round pattern 205 as well.

1 ton crossmembers sit on TOP of the lower framerail, this is why GM didn't need another crossmember for the 1 tons.

You'll need one from '85 or later, as the previous ones are ALL flat for the figure eight (tall) adapter.

Not sure what the application difference is, but there are what I call single hump (what you are talking about) and double hump crossmembers '85+. Not sure if one was used later, or if both were used at the same time, double hump to more easily clear any exhaust setups that weren't "normal", like diesel or heavy duty.
 
From what I am told the frame rails are taller and 1/2 and 3/4 ton wont work. Someone out there has to have run into this problem, this is a conversion from a np208. Thanks Shawn
 
Ask mountainexplorer. The 1991 3+3 we pulled apart we left the crossmember in it, as we couldn't pull it with the exhaust in place.

Crossmembers for 1985-86 K trucks:
15538276 (all)

Crossmembers for 1987-88 V trucks:
15548905 (5.7K, 7.4N, 6.2C/J)
15538276 (292T, 350M, 454W)

So '85-86 were all the same, no question.

'87-88, well, if either of those groups of numbers are HD emissions codes available ONLY in 1 tons, I'd buy that they are different. I WILL go so far as to say that we know there are two different 4WD crossmember designs '85+, which means that it is more likely one set of engines got the single hump, and one set got the double hump. Illustrations in the parts manual are generic regarding shape.
 
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I have a TH400 with a NP205 (round bolt pattern) out of a 1-ton. What I had to use is the crossmember people refer to as the double hump one. My Tranny to transfer adapter doesn't hang down that far like some ive seen for the figure 8 pattern and my case hangs down quite a bit as well.

Trans_crossmember2.jpg
 
My pic is of the crossmember upside down. The portion on the left is where the front driveshaft would be. It sits inside that valley. Your transfercase adapter might hang down farther and if it does you need the single hump version.
 
Actually the one you've got is the one I call the single hump...one hump goes up. The other style is dual "upper" humps.

Both of those crossmembers are used with the same transfercase adapters. The only "major" difference is pre '85, as all crossmembers before then are flat, and all the adapters are "tall".

The original poster is using the '85+ 205 setup, therefore he needs the '85+ crossmembers. I believe the one you've pictured (that I call single hump) is the one that is more desirable for most, unless you have a clocked transfercase.
 
Anyone have a pic of a double hump transfer case cross member

hmm... I thought what I had was a double hump. Do you have a pic of a double hump? what sucks about the setup that I have is the transfer case hangs down really far below the frame rails. I'm worried about breaking something once its ready to be wheeled.
 
I don't have a pic, just imagine the hump thats on the right side of the picture you posted, added to the other side.

The only way you will clearance the crossmember/t-case is to clock. :(

I don't like how far it hangs down on mine either, no easy way around it.
 
Ok I have the single hump one and it does not work so guess i'm shooting for the double hump....looks like a 85 or 86, now where to find one??? Thanks for all the info so far. Shawn
 
Why doesn't it work?

IIRC the '80 and older frames are a different width than later, at least a certain distance from the engine. I couldn't put a 1970's crossmember on my truck, although I had a short drivetrain combo.
 
The first problem I run into is the holes in the middle of the crossmember pictured is 4 3/8" on center and the adapter is 7.5" on center, so it wont bolt to the crossmember and second is if I could bolt the adapter , the transfer case will be pointed down at a steep angle that the 2 piece driveline wont go into the carrier bearing, without pointing upwards, or is this normal?? so there is my dilema. Yes the crossmember will bolt up it just needs that hump on the drivers side to reach the adapter. Any suggestions? Shawn
 
First off, are you even figuring in the transmission mount? You do realize there is one that goes between the adapter and crossmember, right? The bolt pattern is therefore different mount to adapter and mount to crossmember.

I just went and looked at the spare double hump crossmember I have, the mount surface is approx. 1/2" BELOW the frame mount surface. If you measure that distance on the crossmember pictured, from the "drop" (driveshaft) side as installed, yours will be the same.
 
when holding the crossmember in place the difference between the c-member and the adapter is 4.75", yes I know there is an rubber mount on top of the c-member, how tall is the mount as I have not tracked one down yet? Now this is a single hump crossmember like the one pictured in this forum discussion or is this a double hump? Thanks for the help. Shawn
 
Can you view this picture?:
1569adapter.JPG


That's the '85+ 465/205 combo installed in my truck, with the single hump crossmember.
 
ok thanks for the pics, looks like I have the right one after all, wasnt figuring the mount would be that large as the one on my 3/4 ton was only 1/2" thick.
Thanks again!
 
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