Inspecting a rear differential
Elder User
Joined: Jul 2001
Posts: 510
Likes: 0
From: Portland, OR
Inspecting a rear differential
I'm getting ready to swap out a Ford 7.5" rear end assy (whole axle, drum to drum). I bought one from a wrecking yard "u-pull-it" for a good price, assuming it's in good condition of course. I pulled the rear cover, the ring & pinion look perfect. The inner differential gears look like they might have a bit of wear, it was hard to tell but they didn't look perfect-smooth as the ring & pinion. Is this normal? The magnet has some very fine metal build-up on it but no flakes or small chips. Everything spins smooth but I'm sure noise wouldn't be apparent while hand spinning. Does this sound okay?
Thanks,
Mark
Thanks,
Mark
Post Fiend
Joined: Apr 2002
Posts: 7,157
Likes: 1
From: Central Kali
Inspecting a rear differential
You will probably be just fine. I have seen two problems with 9" center sections. The first one was one I picked up at a wrecking yard. I was cleaning it and found a crack on the part that the ring gear bolts to. Took it back and got another one.
The second one was in a 73 that I had put in a 4 speed toploader,302, and a 3.50 rear end. I sold it to a guy. One day the driveshaft broke going down the highway. It broke the tranny mounting ears off and knocked a fist sized chunk out of the bottom of the case. Transmission yoke was split in half. Tranny gears and shafts were fine, built Ford tough,
Still have the parts.
So the guy puts in a automatic, goes to drive it and it wouldn't move.
Turns out the spider gears in the rear end locked up. This is what took out the driveshaft and tranny. I have always been nervous about the spider gears after this.
The second one was in a 73 that I had put in a 4 speed toploader,302, and a 3.50 rear end. I sold it to a guy. One day the driveshaft broke going down the highway. It broke the tranny mounting ears off and knocked a fist sized chunk out of the bottom of the case. Transmission yoke was split in half. Tranny gears and shafts were fine, built Ford tough,
Still have the parts.So the guy puts in a automatic, goes to drive it and it wouldn't move.
Turns out the spider gears in the rear end locked up. This is what took out the driveshaft and tranny. I have always been nervous about the spider gears after this.
Elder User
Joined: Jul 2001
Posts: 510
Likes: 0
From: Portland, OR
Inspecting a rear differential
Hey thanks, I realize there are no guarnantees but I was hoping if it was obvious bad news that someone would warn me not to put it in. I'll post how it went, hopefully all well later today.
Mark
Mark
New User
Joined: Jul 2002
Posts: 1
Likes: 0
Inspecting a rear differential
Mike,
Could you give me a little help? I need to know where I can look on line to find some good pictures of the carrier housing of a 9" truck rear end. Do you know where i can look?
Medi_pac
Could you give me a little help? I need to know where I can look on line to find some good pictures of the carrier housing of a 9" truck rear end. Do you know where i can look?
Medi_pac
Post Fiend
Joined: Apr 2002
Posts: 7,157
Likes: 1
From: Central Kali
Inspecting a rear differential
[updated:LAST EDITED ON 19-Jul-02 AT 11:09 PM (EST)]I don't know of any sites that have pictures of the 9". Doesn't mean they are not out there. You might try a search, so will I.
Found some at http://bronco.com/technicial/upgrades/locking-diff.shtm
Found some at http://bronco.com/technicial/upgrades/locking-diff.shtm
