Big 915 problem...what did I just break?
 

I was driving home from work tonight with no apparent problems with the car. All of a sudden, I heard a loud noise coming from the back and then I lost the gears. The car would not move forward or reverse. Any of you guys here had a similar experience?

Elaborate on loud noise. Year of car? Did the engine continue to run? How does the clutch feel? How does the shifter feel? :confused: Jim

Check the CV joints, one could have come loose, hopefully an outer one.

"lost the gears" If that meant that you locked up your trans and eng stalled than it may be an easy trans fix. May be $400 + labor. If you meant that the shifter and shifting felt OK but car would not move then peek at CV joints.

Guys,
The car is a 76 911S with a 915. The car starts fine, clutch feels ok when depressed, and shifter goes in the gears just fine. Its just the car would not go forward or reverse when the clutch is released, and a clanking noise is heard when I try to accelerate from first (car doesnt go anywhere of course). iVe got to further investigate tomorrow and see if it could be the CV joint.

Very likely one of the half shafts has separated from the trans. The hint is that the gears all engage properly with no obvious irregular noise, there is no forward(or rearward drive) w/o an LSD. Shouldn't be a big deal to repair.

Ahh...there's nothing wrong with your 915 tranny...just one CV that let go...


I bet you have this clapetty-clapetty -sound when pressing accellerator pedal? That's your shaft hitting the road and/or bodywork....so don't try to drive it that way.

The halfshaft can slip out of the drive yoke if a bearing is bad. Cursory inspection of the halfshafts will not reveal this.

Kahuna...are you talking about the tapered roller bearing that is on "differential" in which the "flange shaft" is inserted?? Are you talking about the double row bearing in rear control arm?? I don't under stand what may have happened and how a bad bearing caused the symptions. http://www.pelicanparts.com/support/smileys/dom.gif

My dad's '80 had this happen.

I believe it was the Differential housing that gave way.

He ended up getting a "Good used one" (differential) for $800. Too much in my opinion.

Good Luck, I hope it is only a CV.

Wheeeeewwwww!!!! It turns out that one of the shafts came off the stub assembly on the control arm. Im really puzzled as to how this could happen. It looks like the bolts came loose and two were actually broken in half. Has anyone successfully taken off the nut that holds the stub shaft (flange)? Its the one with the cotter pin thats visible when the wheel is taken off. I have a power tool but that didnt even budge it. I tried loosening it using leverage and a long pipe but just ended up breaking two large socket extensions. Any suggestions?

This happened to me about a month ago. Sitting at a stop light, light turn green, I give it gas and let out the clutch, clunk! For me it was the trans axle side so nothing. I sheared off 6 bolts inside the mounting flange. The flange came right off after taking of the retaining bolt. As for gettign the broken bolts out of the flange i used a drill from the other side and as the bit caught the metal of the bolt, they just turned right out. Don't know if this helps, but you are not alone and it may be the same on the wheel side. Good time to inspect all the CVs, check the torque on the bolts and regrease if necessary.

If the car is on the ground you should be able to break it free with a 3/4" breaker bar and a long extension. I used my jack handle with a 1/2" breaker bar but it sounds like you have already bent this so go bigger!

Elfer,

Glad to hear it was the outer CV that came loose.

If you have access to air, purchase a good impact wrench. Usually works...

Think about using blue Locktite when installing the CVs to the stub axle.

Be sure to use grade 12.9 allen bolts to replace those that broke/missing.

Thanks for all your help guys. Ill get the nut off one way or another. Ive already got an impact gun, but its a little old and a new one might just have enough torque to loosen this. As far as the bolts go, I'll probably purchase them from the dealer, unless you guys have better ideas. My only concern now is the stub shaft. It seems as though the threaded openings where the bolts go in have been enlarged by the vibration of the wheel and the loose bolts. Ill probably end up buying a good used one from a wrecker. Thanks again.:)

I found bolts at Lowe hardware of all places. And that size had LOBRO stamped in the head!

I'd strongly recommend using the OEM screws, locking Schnorr washers all installed through dry clean flanges with the proper torque in this application. I wonder if the failure had to do with this not being done the last time this part of the vehicle was worked on. :D Jim

I got my Bolts and CV gaskets from.........

Pelican Parts!