LS1/4L60E swapped 74 Vette, New converter, Trans Slip?

Hi all,
Just want to thank everyone on this forum for the plethora of information they have provided, and the maturity compared to other forums. A brief bit about myself since this is my first post, I'm a local dyno tuner in Gainesville, Fl that has experience tuning MegaSquirt, Hondata, AEM, and numerous other standalone SD systems. This is my first LS1/Auto/MAF car and am doing it for a buddy of mine. A little about the car: 1974 Corvette with 02 LS1/4L60E, mild cam (unknown specs), Long tubes, Flowmasters, and a less than ideal intake tube setup (Maf connected directly to short stack filter). My buddy said after they had the car built they went to have it tuned, tuner said the TC was bad so they replaced it with a 3200 Stall (Not sure of brand). Before I fix the intake/retune the car, I wanted to diag the trans/tune, because on the road it slips really bad if you give it any sort of throttle >30% TPS. I have purchased several pieces of information to help me through the tuning process, Greg Banishes Basic DVD, Master EFI Tuner by Lasota Racing, and "Tuning the Right Way". When it comes to tuning an automatic, I have little to no experience, mostly trial and error and following the "definitely don't do this" rules of thumb on here. I have tried the trans settings from a stock 02 camaro map, the current map that was on the car from the previous tuner, and tweaking a stock map with recommendations from the Cool-aid write up, but it just keeps slipping. I'm unaware exactly what to look for on the log files to know 100% if its the trans, TC, or the tune. Could someone please help me as I am trying to get this thing done and move on! :banghead: An explanation of how to use the logger to diagnose the issue would be the best info. I have full access to a DynoDynamics 2WD eddy current dyno if that would help. I am using HPTuners 3.0.120 (latest version), and the slipping can be seen from 1:03 to 1:12 on the log file. I am uploading the original tune as well. Thanks in advance!

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Check the fluid. Sounds elementary, common real-world cause though. Past that, there is no ISS vs VSS to look at, so slip in a 60 is often needed to be felt. You can use the scanner out on the rd to hold 2nd (no downshift) and lock the TCC; you should be able to tell if slips leaning on it a bit at that point.

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Originally Posted by Frost

Check the fluid. Sounds elementary, common real-world cause though. Past that, there is no ISS vs VSS to look at, so slip in a 60 is often needed to be felt. You can use the scanner out on the rd to hold 2nd (no downshift) and lock the TCC; you should be able to tell if slips leaning on it a bit at that point.

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I appreciate the response Frost. I double-triple checked the fluid, its right on and smells fresh. I did what you said and had a buddy ride with me to play with the laptop. Locked it in 2nd, locked the TCC, gave it about 60% throttle with no slip. Tried it again in 3rd, started slipping with the TCC locked. By the time I went to drive back to the shop, it was slipping so bad, none of the power was transferring to the wheels. Felt like I was in a manual with the clutch depressed all the way. While looking at the datalog afterwards, noticed the "Current Gear" would rapidly bounce from 1st to 2nd back and forth very rapidly, about every 100mS. I know that's not physically possible so it might be electrical noise? Or possibly the shift linkage is between the gears? Only happened once so I'm scratching my head on that one. Also, at one point during the 5 minute test drive, the wideband went full lean and lost all power, throttle did nothing, then it came back. Seems like the car has a few other issues that can't be fixed with a tune. I'm done spending time on it until he can fix the few minor headaches, then I will be more willing to work on it again. Thanks again for all your help, and if you have some insight on any of these issues please share, any thing helps.