c3 transmission linkage problem?

[William S.]

I was replacing a rebuilt rear trailing arm on my 1969 with automatic transmission. I put it in neutral to get the axle drive shaft to spindle bolts into position and then put it into park to torque them. The first three went fine. When walking behind the car to move the fourth into position I noticed that the back up lights were on while the car was in neutral. Then when I tried to torque the fourth bolt, just as the wrench clicked the spindle slipped. It now turns almost freely as I turn the bolts.

I'm thinking (hoping) this is a transmission linkage vs. a transmission issue. I am going to start doing some research but wanted to check here and see what people think. Any advice would be appreciated. Thanks.

[Michael W.]

Re: c3 transmission linkage problem?

First, it sounds like you left the ignition switch 'on' while you were working on the car. This is never a safe thing to do in addition to possibly burning out the ignition points.

If you've now moved the shifter back into park, the transmission to differential drive shaft should not turn. If you have both rear wheels off the ground and have an open (non-posi) diff, it's normal for the opposite wheel to turn when torque is applied.

[William S.]

Re: c3 transmission linkage problem?

Yes. I did leave the key on while it was in neutral. Agree that was a bad idea.

Car is now in park. Rear tires off. I have a posi differential. I can turn the passenger side differential to rear wheel shaft and the driver side shaft turns in the opposite direction. The differential to transmission shaft does not turn. As I said, I torqued the first three shaft to spline bolts and the shaft seemed locked in position. Now it slips when I try to torque the bolts. Since the differential to transmission shaft doesn't turn it can't be transmission or linkage related, so it seems it must be a differential issue.