Quote:
Originally Posted by kwhauck
Its thinking like this that gives the 45 a bad rep. They can hold a lot of power, people underrate them.
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Just want to add some of my own experience here... and I agree 100% bud! If anyone that is running a 4t40 or 45e and you have access to HP Tuners or DHP you will quickly see that the way GM set up the transmission tune is for a Sunday grocery getter. When they built it, their #1 goal was to try and find happy medium between ride comfort and fuel economy, also why they set factory pressure at 30psi on the tires, when we should run 34-36 minim! Anyway.... back to the trans.... the trans is set up to make the shift as smooth as possible for the end user. Great of your a customer that just uses the car for normal, run of the mill, go to work, get some food, take the family visiting, and so on. BUT, for guys like us this will not do! With the shifts set as soft as they are we are doing major damage to clutch plates and overheating the entire unit. Do this too many times and ka-blewy, you are getting towed.
Increase shift pressure, shorten shift times and raise shift points. Also raise the Torque Converter lock up and you now have a trans that will take just about anything a stage 2-3 NA build will throw at it, and will most likely stand up to a good amount of boost if set up right as well. I say most likely because I will be testing this theory as soon as I can when I add 14psi to a Milzy Stage 2 build that runs 14.1 as of now.
I should add too guys, you cannot set this transmission up properly with the factory trans mount, the one at the very front of your car. There is simply too much play in it, even brand new. I have had many guys over the years argue that one, but trust me guys, I know I'm right on this one. I killed three trans mounts in one summer, and when I say killed I mean killed! Tore the ever living' crap out of them! Put in Milzy's trans mount 5 years ago and have never looked back. With the mount I was able to increase shift pressures by almost 50%!! My trans stays nice and cool no matter how much I beat on it, or how many runs I make. To give you an idea here, I had days at the track where I ran up wards of 30 times in just one day, and there have been dozens...ahhhh yea...
Sorry for the long post guys, but the 4T45E in my opinion is a great trans, GM just had to go a little soft on their tune. Oh, and so you know, when I did my GM Motive Power Autobody Repair and Collision ticket, the fellow that taught me GM electrical for two weeks was the guy that actually designed the trans...lol And a good portion of my tuning training and ideas come from Greg Banish, the guy that sets up the PCM's for General Motors and has literally "written the book" on tuning. He truly is one of the best in the world. For almost two years I was in contact with him at least twice a week when i went through this, and he backs up my methodology 100%!