540", QuickTime/4L80E by Hughes

ateam said

>. I have been informed by JM and trans builders, the 4L80E pump face must be machined flat/parallel, for effective mounting/sealing. I'm prepared to do this. For better up-shifts, I like the design that "releases" frictionals, rater than applying. Some say this is an advantage of the TH400 and 4L80E. Cheers, flyingwedge. :coffee2:

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Just remember that once the pump face is machined (I don't know how much will have to come off to make it flat) the converter will be closer to the flex plate by the amount machined off as you've essentially pulled the bell housing back. this may cause problems with proper "pull-out" of the converter. It should NOT be bottomed out in the pump! I don't know what you plan on using for a converter, but mine is a billet, multi-clutch unit from Joe at Pro-Torque which has pretty thick mounting pads that could be milled to compensate, but I'm not sure how a stock type case converter would work out. Another issue that came up was that the crank pilot on a BB Mopar is significantly larger than that of the GM LS that the converter is designed for, which requires a bushing to be turned and fit to either the crank or the pilot on the converter. I used the latter of the two methods. If the pilot does not engage far enough into the crank and is not a reasonably tight fit, there will be no support on the transmission's input shaft and I don't have to tell you that's a bad thing! Fortunately for me, Chris at CK is a personal friend and Pro-Torque is 5 minutes from me, so working through Chris, I was able to take measurements and get them to Joe. He then gave me an empty case built to my measurements, so I could mock it up to check for proper fit. Once checked and double checked, I brought it back with any corrections that needed to be made and he finished up the unit. It certainly wasn't cheap, but I know it's right!