tomtom123 Posted September 15, 2014 Report Share Posted September 15, 2014 I bought an engine and transmission from a 2004 Chevy Impala SS Indy 500 Edition. The engine I put into my 99 Grand Prix GTP. I was told that my GTP has a different transmission than the Impala. Now, I have found no info on any differences. The only obvious difference is the range selector switch that my GTP has isn't something the Impala came with. Is there any info anyone has on the differences between the 99 GTP transmission and the 04 Impala SS? Quote Link to comment Share on other sites More sharing options...
l67ss Posted September 15, 2014 Report Share Posted September 15, 2014 I bought an engine and transmission from a 2004 Chevy Impala SS Indy 500 Edition.The engine I put into my 99 Grand Prix GTP. I was told that my GTP has a different transmission than the Impala. Now, I have found no info on any differences. The only obvious difference is the range selector switch that my GTP has isn't something the Impala came with. Is there any info anyone has on the differences between the 99 GTP transmission and the 04 Impala SS? just gotta use the neutral safety switch from ur old tranny Quote Link to comment Share on other sites More sharing options...
tomtom123 Posted September 15, 2014 Author Report Share Posted September 15, 2014 Thats what I thought. But someone told me to look into it more because there is 'a big difference between the two' and from what I've noticed so far, they are the same Quote Link to comment Share on other sites More sharing options...
Euro Posted September 15, 2014 Report Share Posted September 15, 2014 I'm pretty sure they'd be about 99% identical. It's just a 4T65E HD that is in the 97-03 L67 cars as far as I know. Same FDR too Quote Link to comment Share on other sites More sharing options...
chevelle3504speed Posted September 15, 2014 Report Share Posted September 15, 2014 The electronics are different in the 2003 and up 4T65e and will not work with the '02 and back PCMs. If you want to use the transmission out of the Impala in your '99 GTP, you need to get a PCM for an '03-05 car that is compatible with 03-05 L67 programming. Quote Link to comment Share on other sites More sharing options...
95 vert Posted September 16, 2014 Report Share Posted September 16, 2014 '04 tranny has the range switch internal. Either a PCM as chevelle said or you can "piggyback" the 4 wires from the 4 pin connector on the range switch to wires on the main tranny connector. Otherwise, the tranny won't shift out of first gear. I apologize for not being able to tell you the correct wires. It's been a while since I've done one. If I get a minute, I'll look it up. Quote Link to comment Share on other sites More sharing options...
l67ss Posted September 16, 2014 Report Share Posted September 16, 2014 '04 tranny has the range switch internal. Either a PCM as chevelle said or you can "piggyback" the 4 wires from the 4 pin connector on the range switch to wires on the main tranny connector. Otherwise, the tranny won't shift out of first gear. I apologize for not being able to tell you the correct wires. It's been a while since I've done one. If I get a minute, I'll look it up. easier way would b to do what i did on my car. car97 monte trans 01 monte ss harness 98 monte z34 engine 97 l67 pcm 99 gtp nss(or range selecter) 02 gp gt what 95 vert said about internal switch is dead on, but the shifter shaft and trans case is the same as any 4t65 i just slapped the switch from the 02 gp on, plugged it in and took off, no spliceing no diagrams etc etc. plus keeps replacement tranny options open Quote Link to comment Share on other sites More sharing options...
tomtom123 Posted September 21, 2014 Author Report Share Posted September 21, 2014 Maybe I read it wrong, the 04 you said has the selector switch? My 04 Impala transmission doesn't have the range selector switch, however my 99GTP does. That's a dirty pic of my 04 Impala transmission Does the range selector switch allow the transmission and car to talk? Or does it just read where/what gear the transmission is in? Quote Link to comment Share on other sites More sharing options...
tomtom123 Posted September 21, 2014 Author Report Share Posted September 21, 2014 Oh nvm. I see what you said. The 04 has the switch internal. Lol I see now Quote Link to comment Share on other sites More sharing options...
chevelle3504speed Posted September 24, 2014 Report Share Posted September 24, 2014 So just to clarify, tom tom could stick the correct range selector switch from his '99 GP on the 2004 transmission and it would work with the stock '99 electronics without other modifications? Quote Link to comment Share on other sites More sharing options...
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