I just had my c4 transmission rebuilt out of my 67 and I tested it out today, it is shifting real hard into park, reverse excetra. It jerks the whole car. I was wondering if this is usual during break in or something is wrong. The fluid is good. And the torque converter is new. Any ideas?

 

any shift kits or was it rebuilt stock....

what do you mean by it shifts hard? It takes a lot of force to move the shifter or do you mean it gives you whiplash?

-Gun

 

Not a break in issue, I am thinking that the modulator is not working right.

It may be that the vac line is disconnected, a hole in the line, etc. or possibly the shop installed an adjustable unit that is not adjusted right.

The modulator will be at the base of the tailshaft, on the bottom, with a vacuum line running to the carb or intake.

 

Sure. What's the idle rpm?

 

yes, the idle rpm can make shifting a pain, high idle will give you whiplash, low idle will stall the engine when put in gear.

 

Everything was stock and I hooked everything back up. The vacuum lines are hooked up securely.

 

idle speed?

 

I have it idling as low as I can get it. My car doesn't have a tachometer on it. It's an automatic and when you put in drive or reverse it jerks the car really bad. Would adjusting the modulator help?

 

If there is an accumulator in the valve body that works with D (1st gear) and R, it may be sticking.


Norm

 

If you had a shop rebuild the tranny i would take it back to them before doing any adjustments. Double check that all is hooked up and filled up proprly and then take it in. They should be willing to stand behind thier work and adjust for free.

ETA: What port is the vacuum line hooked up to and try and put a vucuum gauge on the motor before taking it in.