12 bolt carnage. Salvageable?

[w00dst0ck]

Well, this is the reason I started the LS swap in the first place. I initially had planned on keeping the original drivetrain and just bagging it and enjoying it ...But the rear end locked up one night and I just happened to have a few spare LS motors at the shop at the time.

Fast forward a year, and I'm finishing the Porterbuilt rear setup and finally decided to see what 12 bolt was in the truck and what was going on with it.


Found out someone swapped an HA 3.72 rear end in the truck, which made me extremely happy due to needing a 3.72/4.11 for the 4l80e.

Ring gears look great, I haven't removed the carrier yet, but I'm sure there's some damage on the pinion gears.

My question is, is the carrier salvageable? If so, I can just buy some 4.11 gears and swap them in with new bearings/crush sleeve etc..

[w00dst0ck]

Found a 69 1/2 ton rear end open 4.11 gears for $300. Which will likely need brakes/bearings etc..

Just trying to determine if it's more cost effective to rebuild this one or get another, then have to rebuild it anyway for piece of mind.

[1963c-10]

Looks like more than just ring / pinion and a rebuild to me. Looking at around $200-250 on a set of gears, plus replacement parts and install kit and labor. Labor varies, but I was just quoted $400 to convert my one legger to a posi with me supplying the parts.

What year is your truck? Depending on how much hp you plan to get out of the LS motor, I'd consider a swap personally.

HA shows as a 1965 12 bolt 3.73 non posi

[w00dst0ck]

I can rebuild it myself no problem, so I'm not concerned about labor. Just curious if anyone has more or less re used a carrier that has had this much pinion contact.

Truck is a '65 SWB fleet. Original I6/3 speed Saginaw. Always assumed it had a 3.08 or something similar due to the 3 speed manual.

Just a stock 5.3/4l80e with a mild stall bags and 22's. Maybe 310rwhp at most.

[chevy_mike]

I don't think I would trust it with any HP behind it. Maybe a stock inline 6 but no an LSx motor.

[w00dst0ck]

~300rwhp is nothing lol.

[awbrown]

as long as the gears are not making noise I would run it ..... You will blow the spider gears out of it before the Diff/carrier will break ,ask me how I know..

[Captainfab]

If you're okay with an open diff, you should be able to find just a 4 series open carrier. Many guys upgrade to a posi, so there should be some open carriers laying around.

[BR3W CITY]

I wouldn't be against running it in a beater car, or as a holdover until a new rear end was done being built up...but I wouldn't knowingly put money into parts to be bolted to/around it, and then put it into my '66.

Even if it hasn't suffered unseen or structural damage, I just couldn't in good conscience put a part like that into something I was actively putting money into to make better. I'd always be second guessing it, or counting on it to break...as it seems like Murpheys law is applied according to how many hp you make.

[w00dst0ck]

Not a beater, but definitely not breaking any hp records lol. Might rob a carrier out of one of my 67-72 trucks for now.

If I wasn't planning on doing mild towing with the truck, I would probably run it and not care.

[urmyboyblue]

Should be fine. Looks like the pinion gear is loose- replace the pinion nut, re torque it and keep running (changing the lube of course.) I don't see any weird wear on the ring gear in the picture, so the pinion should be fine. The carrier is munched on, but should be fine.

[w00dst0ck]

Originally Posted by urmyboyblue

Should be fine. Looks like the pinion gear is loose- replace the pinion nut, re torque it and keep running (changing the lube of course.) I don't see any weird wear on the ring gear in the picture, so the pinion should be fine. The carrier is munched on, but should be fine.

My thoughts exactly, I've actually never changed a carrier due to pinion contact, but then again I've never seen one quite this bad.

Like I said, if I didn't intend on towing occasionally, I wouldn't even be having this discussion, and I would run it. It's only really bad on the edges of the carrier.

[Shaky]

http://67-72chevytrucks.com/vboard/s...d.php?t=674444

[w00dst0ck]

Not sure what that is supposed to be aside from pointing out that others have had the same problem.

I've decided to just rebuild the 12 bolt and use the original carrier.

[Shaky]

Originally Posted by w00dst0ck

Not sure what that is supposed to be aside from pointing out that others have had the same problem.

I've decided to just rebuild the 12 bolt and use the original carrier.

Just thought you might be interested in the responses to another thread with the same problem.