Questions on broke rear

[msgn2]

Hello all, I have got some questions on inspecting the *Broke* rear in my car......Driving home with a real bad grinding noise, I ended up breaking the rearend housing ( I think ) because the driveshaft still has the u-joints attched on the rear end side. My questions are this:

1. Does breaking the ring and pinion mean the posi and axles are bad??
2. Does the complete rear have to rebuilt??

Thanks for the info.....

Matt

 

[mikestertwo]

Are you saying the driveshaft turns but the car doesn't move? You will have to remove the cover to see what happen.

 

[msgn2]

Actually, the driveshaft snapped off the rearend housing with the u-joints attached. Even without the driveshaft connected, the car will not move forward. I think I stripped the ring gear so bad that there are peices pinned somewhere in the axles.....

 

[ijames]

I think it is more likely you broke one of the spider gears, but either way you have to pull it down to see what happened. A complete master kit of bearings and seals is only about $90 (one tb sponsor is www.gearsrus.com, check there for exact pricing). That takes care of everything but the axles, ring and pinion, and posi, and you won't have to wonder if any of the bearings still have metal in them. If the spider gears are gone, maybe take the opportunity to step up to aftermarket axles and a new posi as well (not to mention the dreaded c-clips which you need to get rid of anyway if you are under 11.50 ). I went to 30 spline axles and Eaton posi, much stronger and drives like stock.

 

[steve davis]

dumb question? why get rid of the c-clips.

 

[Rocket Power]

dumb question? why get rid of the c-clips.

They are a weak point in the rear end. It is just a tiny u shaped piece of metal holding the axles from flying out the side.

 

[300kGN]

sounds like the pinion ( of ring & pinion gears) broke. The rear u-joint on the driveshaft has "straps" which clamp two of the u-joint cups to the rear yoke. These straps are bolted to the yoke with 2 small bolts each. The pinion gear has a threaded shaft which goes through 2 bearings(in the pumpkin of the rear axle assembly) and then the affore mention yoke, where there is one big nut holding the yoke to the pinion. If the pinion shaft brakes anywhere between the gear of the pinion and the yoke, the gear half will fall inward and wedge itself between the ring gear and the inside of the "pumpkin." If this IS what happened, and you ARE lucky, you may be able to get by with just replacing the ring & pinion, differential & pinion bearings. Worst case, the race lands in the "pumpkin" are damaged and you will need a replacement rear axle housing assembly-the axle tubes and center cast iron section (pumpkin). Have a professional pull the cover and the differential for inspection then repost for advice/solutions.

 

[ijames]

dumb question? why get rid of the c-clips.

NHRA requires it at I think 11.49 these days. Used to be 11.99 and I'm assuming it moved with the roll bar. Axles usually break at the beginning of the splines just outside the spider gears or flush with the spider gear. With the stock GM c clip axle retention the clips are on the inside ends of the axles, inside the spider gears, so when the axle breaks outside the spider gear there is nothing retaining the axle/tire except your fender and the guardrails. The answer is pressed on axle bearings and a retainer at the outside ends of the axles, like the Ford 9" setup. You can use bolt-on c clip eliminators but they use wimpy bearings (the ID has to fit the axle while the OD has to fit inside the bearing seat in the eliminator housing which has to fit inside the axle tube so the OD will always be smaller than stock so the bearings will be weaker and won't last as long as stock). Or get a shop that has the jigs to narrow rears to cut the ends off and weld on Ford ends and use the big Ford bearing which is much stronger than stock. Either way you need new axles, and the axles cost the same for either, but if you go the Ford route you also need Ford brakes. I went that way and used the 11" Ford drum brakes and am very happy. The Ford ends cost about the same as the c-clip eliminators, the axles cost the same (and 28 and 30 splines are the same and you can get whatever lug size and pattern you want), so the cost difference is the extra labor to cut and weld the ends, plus $300 for the drum brakes (and again, you just specify the lug pattern they drill the drums for), plus the labor to set up the ring and pinion and a new posi if you go to bigger axles (I went with a 30 spline Eaton). There are several disc brake choices as well.

 

[chris718]

those types of driveline failures usually destroy the rear oveerunning clutch in the transmission as well.