Swapping from 14B semi-float to 14B full float

[SquareRoot]

Ok cool on the parking brake cable thing, not sure on the locker, do the Detroit's have good enough manors for the street?

Have you not been reading my posts on my 14ff cucv axle in my 85? Lol. The Detroit Lockers in these are Horrible on the street! I'm pulling mine out this weekend and going to open carrier. I learned the hard way.

 

[SirRobyn0]

Ok guys before I get knee deep in a diff swap, I've hatched a plan and have a possible diff. 4.10 FF out of 1974 C20 W/ Gov Loc $300.

Seems like it might be a good fit. If I understand correctly it will be setup for different E-brake cables than my 1984 will have, which kind of sucks but I need new cables anyway. It's from a C20 so the spring perches will be in the correct location where as if it was out of a C30 they'd need to be moved.

The FF axle snout is a little shorter than the SF, but I should be able to get away with the swap without changing drive line length.

Most of you know my tranny is starting to act up and I'll get it rebuilt in few months, the idea is to do the diff swap while the transmission is being rebuilt and the truck is down anyway.

So what do you guys think do I have that about right?

 

[Rusty Nail]

No pix..
Impossible to determine.

 

[SquareRoot]

To follow up on this, I just swapped my SF back and forth with my FF while I pulled out the locker. I specifically measured the difference in pumpkin length. The FF is actually (as mentioned previously) shorter by 1.1 inches. I've run them both with the same driveshaft with no issues. However, under full compression the yoke engagement gets a little sketchy as the axle moves backwards. Fortunately, I used spring plates with provisions to move the axle forward or backwards 1 inch from stock. When I put the FF back in I simply moved the axle forward 1 inch and all is good. The ORD kit and spring plates are way cheaper than a new driveshaft. You have to move the perches anyway to put the FF in a K10/20.

 

[SirRobyn0]

To follow up on this, I just swapped my SF back and forth with my FF while I pulled out the locker. I specifically measured the difference in pumpkin length. The FF is actually (as mentioned previously) shorter by 1.1 inches. I've run them both with the same driveshaft with no issues. However, under full compression the yoke engagement gets a little sketchy as the axle moves backwards. Fortunately, I used spring plates with provisions to move the axle forward or backwards 1 inch from stock. When I put the FF back in I simply moved the axle forward 1 inch and all is good. The ORD kit and spring plates are way cheaper than a new driveshaft. You have to move the perches anyway to put the FF in a K10/20.

Appreciate the info. Since this is coming out of a C20, and going in a C20 I'm hoping not to have to move the perches, but perhaps a guy could drill a hole in the existing perch if need. I think at this point I need to get the diff here and then go from there.

 

[bucket]

Appreciate the info. Since this is coming out of a C20, and going in a C20 I'm hoping not to have to move the perches, but perhaps a guy could drill a hole in the existing perch if need. I think at this point I need to get the diff here and then go from there.

Right, it should be a direct fitment, besides the brake cables. The spring perches will be cast though, with nowhere to drill a second locating hole. It may not be needed with your 2-peice shaft. I believe your driveshaft splines have more engagement than a typical 1-peice shaft with a slip yoke in the trans.

 

[SirRobyn0]

Right, it should be a direct fitment, besides the brake cables. The spring perches will be cast though, with nowhere to drill a second locating hole. It may not be needed with your 2-peice shaft. I believe your driveshaft splines have more engagement than a typical 1-peice shaft with a slip yoke in the trans.

Thanks, that's what I thought should be direct fitment. This makes sense and maybe why I hear so many different answers to the driveline question. So I had mine out a year or so ago to replace the U-joints. IDK how long the front shaft goes into the tranny 4 inches maybe? It's pretty long. The carrier gets bolted up and then the back part slips on. My thought kind of is that if I pull the carrier (which if I remember right has slots in the frame.) If I pull it back 1/2" then the rear shaft only has to make up 1/2". Add to the list I'll need new U-bolts.

I really should replace the springs while I'm in there. Mine has the 5 leaf, I added overloads coil springs, BC they are a bit sacked out. So I'd take advice on what to look for in replacement springs. I should probably call Git's Springs on Monday they are a local shop that will deliver to us.

 

[SirRobyn0]

I just did a little looking around and I see we have to take it in the you know what for shipping. I'll contact the local place on Monday for a quote on springs.