When you pull the 3rd member out of the rear end housing, it would be a good idea (BEFORE you pull the 3rd member itself apart) to put a dial indicator on the back side of the ring gear (opposite side of the teeth) and take a runout reading on it.




There should be no more than .003" deflection of runout on the dial indicator.

After that, remove the differential/ring gear, take the ring gear off of the differential, put the bare differential back into the 3rd member and setup the dial indicator 90° to the differential (where the ring gear bolts up) and take a runout reading on the bare differential.


The differential to ring gear bolts get torqued 60-85 ft/lbs, (in a criss-cross pattern). When you go to reassemble the ring gear on the differential, I wouldn't immediately torque each bolt straight to its maximum torque spec value. I would break it up into stages; 25 ft/lbs, 50 lbs, 75 ft/lbs and then a final torque of 85 ft/lbs.

This will draw the ring gear down evenly onto the mating surface of the differential and not cause it to bind or distort the ring gear or the differential by just going straight to the max torque spec of each ring gear bolt.

 

I'll see what I can do. I doubt the ring gear is still attached to the carrier.

Ranger, were all the 9" carriers the same? Can I put 4.11s on a original 3.25 carrier? Or were they split like the Dana axles?

 

Got it home and on the work pad.

 

They are the same between those ratios. Thanks to MURCMAN58 for sending me some extra slides I can now see the rear axle stuff on a better slide.
1970/ F100 4X2 3300# 9" rear axle with Traction Lock is parts list 181.
1970/ F100 4X2 3600" 9 3/8" rear axle with Traction Lock is parts list 182.

Now I'm not going to look for replacing part number since you aren't going NOS Ford. here is what my Ford slide lists.

parts list 181:
All for ratios 3.25,3.50,3.70,and 4.11.
C9OZ4026B loaded case assembly.
D0OZ4204C bare case.
D0OZ4141A carrier.

parts list 182:
for ratios 3.25,3.50,and 4.09:
D0AZ4026A loaded case.
D0AZ (I think,damn scratch)4204A bare case.
D0TZ4141A carrier.
Different bearings and races between the two axles. I don't mean to kick a Man when he's down, but as I recall you used the bolts that came with your locker. Not Ford ones. I think there lies your problem. I am sure you would have found any run-out when you built it and "set up" that rear end. Big 2X Steve on checking it now but I'm bettin' it is the fault of those bolts.

 

I did use the supplied bolts the first time. They got destroyed so I bought new grade 8 bolts from copper state nut&bolt. When I get it apart we'll see what they look like.

 

AHHHH!!!!!!



Got the rear end all apart. Now I'm not sure i don't have a transmission problem.

The diff is definitely a problem, ring gear bolts backed out again and caused the same damage. But I'm not sure that the diff is the reason why I couldn't drive....

The trans had downshifted right as everything let go. So I don't know... I saw the damage on the gear case and assumed that was the problem. Maybe it wasn't.

Won't know now until I get the axle fixed up and can try to drive it again....

 

Unlike a Dana rear end housing, there are no case breaks for a Ford 9-inch rear end/3rd member. You can install any Ford 9-inch factory ratio from 2.47:1 to 4:57:1 and even lower ratios from the aftermarket.

 

Holy sheep sh_t, Batman! Again? Good Luck finding the problem. We might have to call in Inspector Clueso, to help with this one. Like the others have said- check the bolts and the holes, and runout! Wish I could be more help, but I have little experience in the Diff dept.

 

This looks too familiar....

 

That is seriously uncool. Nasty stuff man.

 

While the 3rd member is out and just for the sake of knowing, I would check the rear end housing, just to make sure it's straight and not bent.

Have you been pulling a lot of heavy loads since the new differential was installed (like much more than the truck is really rated for)?

I don't know what the issue is but, I wonder if there's some sort of stress (axle going into the differential at a slight angle [bent housing]) or, if it's maybe a case of excessive stress being put on the differential from substantially heavy loads that's possibly causing a resonance frequency in the differential that's working the ring gear bolts loose (?).

Something's going on that might not be directly related to the ring gear bolts themselves. It just may be the result of something else that's causing the problem. IF they just came loose once, that might be one thing but, twice --on the same vehicle??? Seems odd.

 

Man, no kiddin'. When you put it together this time you might spray the bolt threads and the threaded holes Real Good with Acetone or Brake Clean. Maybe the gear vendor had some anti rust coating on the gears and in the hole that made the loc-tite you used not grab. 2X Steve, twice in the same vehicle?????

 

wow that sucks , I am seriously scared about my 9" build as it was my first and Yukon brand with richmond gears .

 

I don't know if it's just the angle of the photo but, I don't see the thin washers that should be under the heads of the ring gear bolts (from your photo in post #69).

 

Using my confuser's zoom feature, I *think* I see them.