shifter jumps out of gear

[CHEVY LOUston]

?

The detent is in the transmission. Does your shifter still have the notches for each gear?

Yes I still have notches for the gears. My shifter actually moves from OD to neutral on hard launch

 

[CHEVY LOUston]

To be clear, you are seeing the shifter on the steering column physically move to 'Neutral' while in 'Drive' as you're taking off under heavy acceleration in first gear?

Was this issue was present before you had the transmission rebuilt and before you replaced parts on the column as well as engine/transmission mounts as well as now?

Did you ask your transmission builder about it or inform him this was happening when you took the trans (or truck) in for the transmission overhaul? If so, what did he say about it?

The rooster comb and detent roller control the position of the manual valve in the valve body which is moved incrementally by one detent position each time you move the column shifter from one position to the next...The rooster comb is part of the transmission's internal shift linkage, which includes the manual valve actuator arm that hooks into the manual valve itself in the valve body; the rooster comb slides onto the selector shaft via two flats machined into both. The rooster comb is secured to the selector shaft by a 15mm nut that has to be tightened to about 15-20 ft lbs otherwise it could come loose. Otherwise the rest of the external linkage is mated to the selector shaft via a 15mm nut on the outside of the transmission and takes about 20-25 ft lbs.

Is that nut tight and exterior linkage correctly set up and in good shape?

Yes I see shifter on column physically move. This was present prior to rebuild. I told my rebuilder about it. After he started the rebuild he told me it had nothing to do with anything internal of the transmission. He suggested replacing engine and trans mounts. I did that and didn't experience a change. I did get to go under the truck this morning and found a bushing on the linkage that goes into the frame and also has a spring was popping out of the hole in the frame. I also feel that spring has lost its tension. Where can I get these parts and would you have a part number for them? the trans actually shift very well. I would not be opposed to replacing all the bushings on the linkage. I cannot find anything online for the parts needed. The internet seems to think all OBS have shifter cables.

 

[Schurkey]

I'd expect any Chevy stealership would have the part numbers, maybe even the actual parts.

 

[NickTransmissions]

Yes I see shifter on column physically move. This was present prior to rebuild. I told my rebuilder about it. After he started the rebuild he told me it had nothing to do with anything internal of the transmission. He suggested replacing engine and trans mounts. I did that and didn't experience a change. I did get to go under the truck this morning and found a bushing on the linkage that goes into the frame and also has a spring was popping out of the hole in the frame. I also feel that spring has lost its tension. Where can I get these parts and would you have a part number for them? the trans actually shift very well. I would not be opposed to replacing all the bushings on the linkage. I cannot find anything online for the parts needed. The internet seems to think all OBS have shifter cables.

Not sure, to be honest - you can try the dealership as suggested above or GM Parts Direct...Rock Auto, LMC Truck or other places may also have them. If you strike out with retailers, on-line or brick-and-mortar, I'd go to a junk yard and yank the parts you need.