Jumps from PARK into DRIVE on its own

[markusm]

I have a first generation assembled Explorer with parts from '91 thru '94. Over the weekend I was letting the engine warm up in the driveway (with automatic transmission in PARK) prior to running some SeaFoam through the throttle body. With the hood up I was leaning into the engine compartment from the drivers side tidkling the throttle by hand when suddenly the vehicle went into DRIVE on its own and crashed into my garage. Luckily I was not hurt and relatively little damage was done. Now the transmission is in forward DRIVE no matter what position the shift lever is in. The shift lever feels "right" with all detents, etc. but there's no PARK, REVERSE, NEUTRAL, only DRIVE. What could have spontaneously broken to cause this? I should add that before the truck jumped into gear I had noticed that I couldn't rev it up while it sat in PARK. I now realize that it may have been under load like trying to rev the engine while applying the brake. Any insight into this problem will be appreciated.

 

[PopRichie77]

Check the linkage at the trans for proper movement, if it is ok, it is probably the forward clutch is shot as stated in another post by JK80. Trying to rev the engine welded the clutch plates together.

 

[JK080]

If it drives forward in reverse position without any bind up then I would suspect the linkage, but if it binds then I would think the forward drum is welded down.

 

[markusm]

Thanks, I'll be checking the linkage tonight.

 

[markusm]

I checked the linkage to the transmission and it is sound. Moving the shift lever in the cab actuates the manual shift arm on the tranny. I can also disconnect the cable from the shift arm and move the shift arm by hand although the transmission remains in DRIVE. I guess my next step will be to drop the pan so I can satisfy myself that the Z-link is connected and working properly.