Have a 97 monte with a 3.4 la1, 4t65. 4t65 is from a 2001 monte ss. Harness and pcm are from a 2000 lumina. According to the web both donor cars have the same ratio. It does have a positrac unit. Whats up with codes popping up for the gear ratios not matching? Thanks

 

First, what are the actual codes you're getting? There may be more to this.... I may also be something different in how the trans and PCM interact at the data level....

 

Unsure of code number. I used a scanner at oreillys. It said "gear ratios dont match" thanks

 

Doesn't the LA1 use a 2.86:1 4t65e, and the Monte uses a 3.29:1

 

Could the prob, my info on the gear ratios came from google, so you know how that goes. The pcm is for a large port 3100 from a 2000 lumina thanks

 

Thats interesting that you have the LA1 3.4 in your 97. But Mike(chibi) is right, LA1 used the 2.86:1 and the L36(3.8) would have used 3.29:1. So that sounds like your issue.

 

Found a more reliable website, (wiki lol) it said 2000 luminas had 2.92s, so that explains it thanks for the help

 

I also think that the 2000 lumina would have had the 3.29:1 transmission too, not 100% sure, but if thats the case then that would be your issue. 2.86:1 transmission with a pcm from a car running a 3.29:1

 

The scanner should still return the code associated with it. May want to have it rescanned.

 

It was code po 730 thanks