JIMs70K25
1/2 ton status
I am swapping in a 1984 SM465/Np205 combo in place of a 700r4/208 in my 1986 K5. Will the auto cross member work or do I need to find a manual one?
CK5
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cross member ?
- Thread starter JIMs70K25
- Start date
. If you have flat cross member now I would say yes. And if you still have the old factory bushing, replace them with some poly bushings or there's a good chance your adapted will crack....especially if you got a heavy foot.
You need the crossmember from an '84-down truck.
'85+ uses a "shorter" adapter, as the crossmember sits higher. IMO a better setup. No way around that in your case, you have to use the tall adapter/flat crossmember.
'85+ uses a "shorter" adapter, as the crossmember sits higher. IMO a better setup. No way around that in your case, you have to use the tall adapter/flat crossmember.
JIMs70K25
1/2 ton status
Thanks, I do have a cross member from a 71, I think it might be too narrow. I guess I'll find an older cross member. Will an automatic cross member work? Thanks!
AFAIK all the crossmembers are essentially the same, as long as they are the same vintage. (73-84, 85+)
It does get a bit tricky with the earlier stuff, I vaguely recall when I put my '81 frame together with various other '81+ parts, that a '73-80 crossmember was very close to not fitting (or actually not fitting), as the frame seemed too wide on the '81.
The two things that really matter are width of the crossmember, and where on the frame the crossmember will be located based on trans length. If you have the '86 crossmember, just make sure whatever you get is the same width, and I'd just make some rudimentary measurements as to where the crossmember will end up with the new drivetrain vs. old.
Again, hazy memory, but I recall that the '84-down 465 trans mount brought the crossmember quite a bit forward from where it was with whatever trans was in place on mine prior, which was what caused the width issue I was seeing. I don't believe there was any frame width/geometry change '81-91 in the area where the crossmembers could bolt up, but can't comment on prior.
It does get a bit tricky with the earlier stuff, I vaguely recall when I put my '81 frame together with various other '81+ parts, that a '73-80 crossmember was very close to not fitting (or actually not fitting), as the frame seemed too wide on the '81.
The two things that really matter are width of the crossmember, and where on the frame the crossmember will be located based on trans length. If you have the '86 crossmember, just make sure whatever you get is the same width, and I'd just make some rudimentary measurements as to where the crossmember will end up with the new drivetrain vs. old.
Again, hazy memory, but I recall that the '84-down 465 trans mount brought the crossmember quite a bit forward from where it was with whatever trans was in place on mine prior, which was what caused the width issue I was seeing. I don't believe there was any frame width/geometry change '81-91 in the area where the crossmembers could bolt up, but can't comment on prior.
JIMs70K25
1/2 ton status
Thanks. I found a cross member local from an 84 GMC with an automatic. I checked the frame, looks like no interference, it will move forward.
