Why does my automatic transmission slam into gears/

Manual transmission ... clutch worn. Automatic transmission ... that will happen if tickover is too high.
Fix the tickover issue, probably mass airflow sensor or air leak, then gears should sort themselves out.

Check the fluid level. The symptoms you describe can be caused by low fluid level. If this is OK, I suggest you take it to a specialist automatic transmission repairer urgently.

I had this happen on a 2001 Silverado. The shift cable end slipped off at the transmission. Popped it back on and it worked. Don"t slam the shifter or this happens.

is there any codes. there is a transmission module

Have your dealer check the sincrenisers .

For Automatic transmission problem,click the link below:---- Automatic transmission troubleshooting:----

http://howtobyme.blogspot.com/2011/11/automatic-transmission-will-not-go-into.html

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Automatic transmission shift lever issues?-------

http://technoanswers.blogspot.com/2012/01/automatic-transmission-shift-lever-hard.html

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AUTOMATIC TRANSMISSION FLUID LEVEL? --

http://schematicsdiagram.blogspot.com/2011/07/how-to-check-automatic-transmission.html

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AUTOMATIC TRANSMISSION FLUID AND FILTER?

http://schematicsdiagram.blogspot.com/2011/07/how-to-change-automatic-transmission.html

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Transmission fault light on car dash?

http://schematicsdiagram.blogspot.com/2011/12/transmission-fault-light-on-car-dash.html

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Transmission shifting problem?

http://schematicsdiagram.blogspot.com/2012/01/transmission-shifting-problem-on-toyota.html

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Transmission Slips out of 2nd gear?

http://repairhelpcenter.blogspot.in/2012/02/transmission-slips-out-of-2nd-gear.html

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OD light flashing and transmission fluid leaking?

http://repairhelpcenter.blogspot.in/2012/02/od-light-flashing-and-transmission.html

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Why Transmission fluid leaks near radiator?

http://repairhelpcenter.blogspot.in/2012/02/transmission-fluid-leaks-near-radiator.html

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Transmission fluid leaking?

http://technoanswers.blogspot.in/2012/02/ford-windstar-transmission-fluid.html

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****** wont go in reverse?

http://technoanswers.blogspot.in/2012/02/dodge-neon-wont-go-in-reverse.html

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Automatic transmission will not go into reverse?

http://technoanswers.blogspot.in/2012/02/dodge-automatic-transmission-will-not.html

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Transmission is making buzzing noise?

http://technoanswers.blogspot.in/2012/02/transmission-is-making-buzzing-noise.html

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This will help.

Thanks.

Have you tried changing transmission fluid and filter?

Im having the exact same problem, word for word, with my 1995 3000gt! Anyone have any ideas on how to fix it please???

I recommend taking the vehicle to a Transmission repair shop . It could be the shift valves are defective , low fluid,or TCM needs reprograming.

you may wanna try to service the tranny and change the filter and screen and add sum lucas transmission treatment,if this doesnt help you will need to replace the transmission more than likely