My 70 k5 has an open 12 bolt that has dark specs on some of the ring gear teeth. Would even call it mild pitting. Has 3.73 gears. Just pulled the 12 bolt from my 72 K5 and found it has a gov-lock but 3.07 gears. SInce It looks like I'm going to need a new set of gears anyway, which rear end should I put them in. Stock 350 with th350 and NP205, tires no bigger than 33 (keeping the 3.73 ratio). Shouldn't be wheeled hard. Looking for opinions. Frank
CK5
Register an account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members.
12 bolt options
- Thread starter fesser
- Start date
bigbadchev84
1/2 ton status
Im a little lost in your wording. are you asking if you should install the new 3.73s into the axle that has pitted 3.73s or the one with 3.08s
Or are you asking if You should run the 3.08s or the 3.73s in your truck?
Or are you asking if You should run the 3.08s or the 3.73s in your truck?
I wouldn't waste time trying to either save or re-use a Gov-Loc.
You're not using a very large tire or wheeling hard, but they are notorious for failures... I'd probably run an open diff instead, or if you think you need a locker or limited slip you could think about something aftermarket. Once you convert to a regular carrier you'll have more options.
You're not using a very large tire or wheeling hard, but they are notorious for failures... I'd probably run an open diff instead, or if you think you need a locker or limited slip you could think about something aftermarket. Once you convert to a regular carrier you'll have more options.
bigbadchev84
1/2 ton status
X2 on what Greg said. Gov-Locs are ticking time bombs and are iffy at best as far as counting on using them as a limited slip.
If anyone is still reading this...I have a 78 12 bolt that is still in the truck that donated the front end for the 70. Very well maintained but open diff. Would having the spring perches replaced on the rear end to fit the 1st gen be the cheapest way to get rolling again? Granted I wouldn't have a posi but the brakes, bearings, seals, and gears are all good in the 78 rear. I am working on a budget. and am way past the finish date imposed by my daughter.
shovelbill80
1/2 ton status
or you could find a late 30 spline 10 bolt, i'm thinkin 89/90/91, with the G80 and 3.73 already in it. probably get it for close to nothing. i know i'd rather weld than set up gears.
It all depends on what you know how to do yourself, or what people charge locally for various repairs.
The comparision is the cost of a new 12-bolt carrier and gear setup vs. the cost of cutting and re-welding the spring perches. It seems like the welding would be cheaper, but it depends on who you find to help you.
Do you own any tools like a 4-1/2" grinder? You could use cutoff wheels to carefully undercut the welds on the spring perches all the way around, then hammer them off. A flap wheel will smooth off the axletube and perches and get rid of the residual welds. Then you can set up the new axle under the truck and set your pinion angle with the perches loosely in place on the axle and the full weight of the truck on it. Mark the locations of the perches carefully and then take the axle to a local welder to have the perches burned-in.
Doing a lot of that "prep" work in advance should save you some coin.
