What's new
CK5
Register an account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members.

Need a new transmission crossmember

@TnA Think it'd be possible to re-use the existing rear mounting holes for the new crossmember? Maybe as the front mounting holes on the new one or as a way of locating it before drilling the rest of the new holes? Just thinking out loud but it'd be nice to have a fixed point to work off of to eliminate any mis-measuring :whistle:
 
chris85 said:
You getting him some front driveshaft measurements? Hoping your doubler will be close to what I need for the magnum.
Click to expand...

Yes, I'm curious to see how low these would hang under the frame. With the flat design I would think 2 of these (1 w/ driveshaft offset and 1 without) would make great skid plate platforms.
 
W
nvrenuf said:
@TnA what are your thought on going over the driveshaft instead of under it?

Back to the measurement, I was talking about the width of the crossmember from engine to tcase - not frame rail to frame rail.

As far as using factory mounts, would it be the pre '85 2 pc style or the '85+ 1 pc style? Or could you go with a universal bushing? Both the factory 2 pc and the universal styles would require a "pocket" on the underside of the crossmember.

Edit: I got your PM but I haven't been home to take measurements. I hope to do that this weekend.
Click to expand...

Well... I was thinking everyone would be running the new style mounts by now, but it appears that's not the case at all. And thinking more on it, the older style mounts would probably be a little more compact. So I might have to redesign everything for the old style mount system. Not sure exactly where to go with this now.
 
I'm not sure I like the idea of going over the driveshaft - I know it hangs down when going under the shaft, but the gives you something to bolt/weld a skidplate to. Especially if you add in a second flat one behind as nvrenuf suggested.
 
My plan is to put my front crossmember under my Doubler adapter which uses the early style busing but I think it is spaced a bit wider.

Would a bushing like this be more compact than a earlier 2 pc?

mount 3.jpg
 
nvrenuf said:
My plan is to put my front crossmember under my Doubler adapter which uses the early style busing but I think it is spaced a bit wider.

Would a bushing like this be more compact than a earlier 2 pc?

View attachment 259729
Click to expand...

They are probably about the same. I think the factory ones are about 1" thick or so, those look to be about the same.
 
Hey guys, I just wanted to post up and let you all know that I haven't forgotten about this - just been really, really busy the last little while. I managed to pick up a set of the older style trans mounts the other day so I can measure to see if it would be possible to make a crossmember that could bolt to either the old style (rubber on top, rubber on bottom) or the new style (rubber on top with studs sticking down). But I haven't had a free moment to do anything with them yet.
I'll post up again when I can make a little progress...

-Darren
 
Shawn said:
That being said, I just found a rare 1991 K30 4L80e 4x4 crossmember and bought it for $50. Its being shipped now. No pictures of it yet.
Click to expand...
What is the difference between this one-year-only crossmember compared to any '87-'90 crossmember?
 
thatK30guy said:
What is the difference between this one-year-only crossmember compared to any '87-'90 crossmember?
Click to expand...

I'd love to know any differences as well, since the adapter is basically a 400/205 piece I can't see where it would be different.
 
One year crossmember -
I doubt this will be the reason but I think the 91 was the only year of the 4l60 - transitioned from 700 but before 4l60e.
 
+1 I'm curious as well and wondering if it bolts in the same holes and just has an offset built in at the mount for the extra length of the 4L80E or something. FWIW I have the adapter off a '90 Burb with a 400/241 and it wouldn't bolt up to my 4L80E, the paws on the bottom hit the trans and kept them from bolting together.
 
NorCalAnthony said:
+1 I'm curious as well and wondering if it bolts in the same holes and just has an offset built in at the mount for the extra length of the 4L80E or something. FWIW I have the adapter off a '90 Burb with a 400/241 and it wouldn't bolt up to my 4L80E, the paws on the bottom hit the trans and kept them from bolting together.
Click to expand...
Since the 80E is longer than the 400 the adaptors are different in the mounting tabs at the crossmember side. One has the ears forward of the other. I'll see if I can find a pic somewhere.
 
Here's a pic that shows the difference between the mounting ears. Notice how the left one has them forward of the right one.

April%2010%20pics%20010_2736x2052.jpg
 
nvrenuf said:
I'd love to know any differences as well, since the adapter is basically a 400/205 piece I can't see where it would be different.
Click to expand...
I'm betting 99.9% that the crossmembers are the same thing. Just the adaptor makes the difference with positioning. I'd say you could install an 80E/205 right up to the 'member without relocating any holes since the adaptor ears make up for the slack.
 
There are several pics all over the interwebs of guys trying to use the 400/205 short adaptor behind an 80E and it not sitting squarely to the mount surface hence the reason for those aluminum spacers made. The issue with these adaptors not fitting correctly is in those ears themselves. I believe Brett had some pics up on his Doubler build or I think it may be an old thread from Leadfoot.
 
That 91 crossmember I got was the wrong one so scratch what I said. It was for the newer GMT400 truck. That being said I think it can be cut down to make work but it will need the shorter round adapter.
 
Nothing fancy but showing the position of the bolt tabs/feet for the differences. Keep in mind the shifters are different, too.

4L80 adapter 004.jpg
 
You must log in or register to reply here.

Latest Posts

Top Bottom