Impala Police Package Upgrades

I was curious if there are some compatible parts between my 05' GTP and a police package Impala. I heard they have the same L67 and that the police package has a tuned PCM with firmer and more performance oriented shiftpoints, fans turn on earlier, no rev limiter and speed governor etc, and that they had external trans and oil coolers.

So is a PCM from a 05' impala police package compatible with my GTP? Would that be an easy performance upgrade? I was planning to do an external trans cooler with a seperate fan and relay, but I would love to do an external oil cooler since I do over 100mph on roadtrips all the time.

Eventually I have an IC planned, ported SC with 3.4" pulley, 1.9RR's and headers.

a) all the suspension components swap over

b) you CANNOT use their PCM since they DID NOT come with L67s...ever.

c) a trans cooler will kill your transmission FASTER. leave it out of the system. and if you really do over 100mph constantly on road trips then i feel sorry for your car.

what did they have for engines?

2000-2005 came with L36 3.8s
newer ones came with the 3.9 LZ9, and im not sure if 9C1 cars came with the LZE 3.5 or not. But yeah 9C1s never came with L67s

Bio, I'm not sure why a trans cooler will kill a transmission sooner????? Can you explain???
Thanks Lambo

not sure why it'll kill it sooner, but i have seen on a website that they found our transmissions absolutely don't need a cooler.

ZR1 got one point. the other point is that it introduces many more places for leaks and its much easier to accidentally introduce other contaminants into the system.

either way, just leave it be. the transmission is fine on it's own.

Bio248 said:

the transmission is fine on it's own.

Click to expand...

well not fine lol - they're pretty crappy, but you're not any better off with a cooler

well, thanks for the info. I can't say that I agree with the whole tranny cooler situation. If the number one killer of trannies is heat and worn fluid not protecting parts, then anything to reduce heat must be a good thing. If you relocate the fluid in front of the radiator, you are not only moving it away from a much larger heat source, (the engine compartment itself), but you are improving the efficiency of the radiator because it does not have the heated tranny fluid flowing within it now, only coolant, so it's a two for the price of one deal really.
Nice aftermarket coolers from B&M have their own fans and with a relay and temp sensor you can have awesome cooling, install an aftermarket guage to keep an eye on your tranny temp.

I USED to drive 100mph on long road trips...but just two days ago I got a ticket. So now I'm the slowest driver because I'm broke!

The GM trans cooler is a nice upgrade and was designed to help with HD applications like police cars. The only way it would hurt is if one of the lines broke or you installed a used clogged/contaminated trans cooler. The GM trans cooler has some nice lines with it and makes it plug and play.

One of the best 4t65 rebuilders(Dave @TEP) suggests one for his higher HP street builds if that gives you any piece of mind.