While changing the neutral safety switch on a C4 which I am putting in a 68 Mustang,  I seem to have broken the internal linkage on the kickdown lever.  Does anyone know if this can be fixed by simply droping the pan and accessing?  

The kickdown lever is above the valve body, so you'd have to pull that.  What makes you think it's broken?  It's a shaft with a short lever on the end - not real complicated and not real prone to breakage.  

Agreed, it just pushes against a valve on the valve body, so it is something that rarely needs replacement unless the trans grenades it self...

If memory serves the kickdown lever shaft slides in and out of the case a bit, could it be that the shaft just slid in too far and is "missing" the valve body?

Try grasping the threads of the shaft and pulling it outwards and see if it reengages the valve body. Worst case you'll have to drop the pan and valve body for a visual.

HTH...
Mark  

Thanks,

  The lever was spinning a full 360+ with no resistance before the it disappeared into the transmission.  Do you have a diagram of this assembly

Thanks

Mike  

OK, that's different.  

In this pic I found, the kickdown is the lever over the blue marks on the drum, the one with the little "hook" in the end of it.  

In this VB picture, from the top is the tension pawl for the manual shift (black arm), then the manual valve which is controled by the shifter, then the kickdown valve is the little shaft sticking out of the casing just below the manual valve.  The lever bears against that little shaft.

You can see that it's a bit of a trick to get the manual lever in the right spot and land the kickdown in it's little spot too when installing the VB.

There's the possibility that someone "fixed" the kickdown by modding the lever somehow, before you got to this point.  If the lever is in place, it should not be able to flip all the way around - it'll hit the VB at some point.  

Thanks Falcon,

    Looks to me like I simply broke the lever (based on these photos)  I should be able to do this repair from under the car without having to pull the transmission.  Will probably tackle this one next weekend.  

You can just drop the VB to access the lever.  Two cautions:
1) lots more fluid will come out when you remove the VB. It's not very tasty, keep extra towels handy.

2) the VB retaining bolts are torqued in in/lbs, the spec is 80-120 in/lbs.  Be sure to use the proper torque wrench to replace the bolts - don't guess.  Over torquing can warp the VB and cause the internal valves to stick.

Set the shifter in neutral and note where the manual linkage engages the manual valve so you can get it back in the right spot.  With the nut removed, the kickdown shaft should just slide right into the trans.

One other trick that I find useful - I remove the detent spring from the VB before I install, then replace it after the VB is seated in the trans.  One less thing to fight with.  The small bolt torques to 20-40 in/lbs.  

should I go out and buy the manual?  

Try to find the ATSG .pdf online. Definately worth buying if you can't find it online. Not req'd if you are only going to remove the valve body. If you are going any further (or inside the valve body), make sure you have the manual.