Wildbill040

I'm done with the weak *** 4L60! I just lost the 7th one! I've detuned very expensive HP trying to get one to last at least a summer to no avail. I have more than $10K in these losers! So, it's either a 4L80 or a T400. I don't want to lose a 4th gear, so, the T400 is a last resort.

Will a 4L80 fit into a GTO tunnel? What I have found on the interwebs is it won't be difficult over coming the electronics and converter, but, I haven't found much on cross members, driveline fitment, shift cable differences or if it'll even fit the tunnel? I don't want to cut it up (a little nip or tuck would be ok).

I've also seen different thoughts about which gen of the trans to use on F-body applications, but none for the 04 GTO, which has a one year only PCM.

Anyone?

dw456post

4L80 will fit a 2004 GTO. I have attached a pic of the only place you have to trim for the electrical plug. If you want a ready to bolt in crossmember, call Hutter Performance.
Call PCMof NC for the 4l60 to 4l80 conversion harness. Find someone with HPTuners to modify your trans tables, get a new converter, flexplate, & driveshaft and you should be good to go. Stock shifter works but you have to bend the shift rod to miss the VSS plug on the trans. Good luck, you will like it.