which rear will bolt up

[bigun]

I have a 85 c20, 4 speed and a coporate 14 bolt SF rear end that may need to be replaced it makes a pinging noise when you go back in the throttle after slack in the driveline, what later model rear ends will work with minimal mods?, I'm a welder/fabricator, so I can move perches etc. thanks for any help

 

[Georgeb]

You sure it's not a u-joint?

 

[87scotty]

If I'm not mistaken thats a pretty good rear end rebuild or find another?

 

[bigun]

u-joints are tight, rebuild is about $700-800 that I don't have and newer ones are easier to find but not sure if they'll work, that was the reason for the question

 

[bucket]

Sounds like a sticking/seizing u-joint... so it might still be tight.

If you can move perches, you can use pretty much any full size truck axle you want. Newer body style trucks tend to have a wider housing, since the wheels keep getting more and more backspace.

 

[Georgeb]

It may be that what you are hearing is slack in the side and spider gears being taken up when you go from coasting to loading the driveline. I have had many trucks that did that for many, many miles. The noise is just amplified by the drive shaft. I would take the cover off and inspect for wear and excessive backlash before I jumped off the cliff. In fact my 78 c10 has almost a quarter turn of slop and has been that way for 16 years. I will admit it is worn out and needs to be replaced but I just need two more years out of it.

 

[highdesertrange]

bad u-joint, I don't care if it's tight you have a dry one. highdesertranger

 

[bigun]

I took the cover off and gears still look good, you can move the drive shaft 1/8 turn or better before spider gears make contact, I assumed that was my noise, but I will recheck u-joints, thanks for the info guys

 

[adamj]

Question was never answered here: what is the axle swap compatibility?
I need a new rear end, I have the 9.5" 14 bolt, but going to rebuild so might as well find a FF14 bolt. Which axles swap right over without relocating perches? I have an 87 3/4 ton suburban, I'm fine with the 3/4 ton drum brakes, don't need discs.

 

[highdesertrange]

I believe any single rear wheel 14ff out of a PU or suburban will bolt right in. a van will not the spring pads are in a different location. just use a tape measure. highdesertranger

 

[CSFJ]

I believe any single rear wheel 14ff out of a PU or suburban will bolt right in. a van will not the spring pads are in a different location. just use a tape measure. highdesertranger

I thought there was a difference between 1 ton and 3/4 ton on the shock mounts also?

 

[highdesertrange]

on the duallies there is some one else needs to chime in for the singles. highdesertranger

 

[adamj]

I read that the "pinion snout" on the 14BFF is longer than the 14B sf, so I would have to get the right driveshaft too... I think I'm going to stick with the SF 9.5", I don't off road that hard anyways, just some light towing of a pop up camper.
So any 9.5" will mount right up? Shock mounts too line up?
From 81 up to when?

 

[CSFJ]

Yeah, the semi-float was a 3/4 ton only axle. As long as it came in a square body, it will bolt right in. As long as the gearset matches (if you have 4wd)

 

[bucket]

on the duallies there is some one else needs to chime in for the singles. highdesertranger

ALL the 1-ton trucks got narrower perch spacing and relocated shock mounts, even if they were SRW. This also applies to the uncommon crew cab C20.