transmission crossmembers

[1984gmchighserria]

I have a 700r4 mated with a 208 just wanted to no what trans crossmembers are interchangeable can anyone help? Thanks

[Grim 82]

Which one do you have now, and what are you looking to do? My SM465/np208 had the flat crossmember, and I swapped to a 700r4/np208 and used the s-curved crossmember from an 88 suburban. It mounted on the frame in the exact location but the hole centers were off, so I just drilled 4 new holes.

[1984gmchighserria]

I had a custom one on but wasn't very stabile. What I am looking for is the s shaped one that is on other gm models that will bolt to the frame without having to drill in the frame. Thanks

[Grim 82]

If this is for your 84, you will most likely have to drill the new holes for the s-shaped one to bolt up. My 82 K10 (sm465/np208)and my 84 K10 (700r4/np208) both had the flat crossmembers. My 88 burban had the s-shaped one. I'm not sure what years or models they put those ones on, but if yours was originally equipped with the flat one like my 84 was, the location is the same, but the holes are spaced differently.
 If I remember correctly the shape of the crossmember wouldn't allow for drilling the crossmember to match the holes in the frame. You could always go custom again, or aftermarket, but I would probably just get one from a junkyard and drill some holes.

[1984gmchighserria]

Yea its for the 84. I thought they came with the s shape can you take a picture of the flat style and I am goin to the junkyard tomorrow.

[Grim 82]

Yeah I'll post a pic when I get home.

[1984gmchighserria]

Thank you grim82

[1979C20]

The s shaped crossmembers were for the vehicles equipped with catalyctic converters

[Grim 82]

My 82 and 84 both had catalytic convertors with the flat crossmember. They were prone to cracking, so that could explain the s-shaped ones in later models, but I'm not sure.

Here's the flat one from my 82 and the curved one from the 88.

[1984gmchighserria]

Is it safe to assume that all flat ones are the same no matter what trans it was bolted to for 73-87gm and where did they crack. Thanks again

[Grim 82]

I can't confirm which ones were on which years with which trans, other than the examples that I have had experience with. I've also never personally had an issue with the flat crossmember, but based on the experiences of some of the other members here I switched it out before I did. They could tell you more about them. I would look for the later years to find the curved one. Also, if the mount needs to be replaced, it's only one part instead of buying 2 for the flat member. Happy hunting

[1984gmchighserria]

Does your flat cross member have a dip on the driver side and what bolts up to the 208 I found on that's for a 2 wd and is 75 a good price because thathow much they want for it. Seems to high to me thanks again

[Grim 82]

That does seem excessive.  The parts listings for the trans mounts indicate 3 choices, a 2wd type from 73-87, and 2 different 4wd applications, either from 73-84, or 85-87. I'm not sure, but I dont think the 2wd one would work for you. As far as the dip, what you can see in the pic is all I can tell you. When I removed it I put it all in storage a couple hundred miles away.

[1984gmchighserria]

I didn't see just thought id ask where did you get the parts listing?

[Grim 82]

That was from my local parts supplier.