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Potential Tuner
4L60E starting in 2nd when selector in 2nd
I think I figured it out. Wasn't sure how to delete post. LOL
Last edited by jaybob; 08-15-2022 at 08:48 PM.
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Well at least other people who find this will know what to do.
Mine's always done that, always been kinda annoyed by it, never really dug into finding out why some platforms do 1st gear starts in D2 and others do 2nd only.
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Potential Tuner
TRANS-->SHIFT SCHEDULING-->UPSHIFT D2 2ND
It's a part throttle shift table that defines shift speeds when the selector is placed in 2nd. They are zeroed out on this car so I assume its defaulting to 2nd gear at a dead stop. I'm going to put the 1-2 speeds from the normal table into this one and hopefully its corrected. Car isn't here yet to test it.
This PCM is from an 02 Firebird. I looked through some of the small amount of cars I've worked on .My 99 Camaro doesn't have it but my 01 does, and every truck file I've checked has it. 2004 GTO also doesn't have it.
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Yep, mine ('06 E40/T42 truck) that does 2nd gear starts is also zeroed out there. '06 GTO is not zeroed, but I don't know for sure how those behave in D2. I'll give it a try.
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No, got that backwards - it's the GTO that has all the D2 tables zeroed out.
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My 2000 LS1 Camaro was advertised as having 2nd gear start. Supposed to be used in low traction situations.
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Tuner
FYI
As a transmission builder, I was always taught that GM made M2 in a 4L60E a snow type gear. M2 is 2nd only for the gear ratio. Low gear is 3.06 (so D1, M3 low gear, M1) X 3.42 gear ratio is a 10.46 overall gear ratio. That makes it very easy to spin tires in the snow. 2nd is 1.62 X 3.42 is a 5.54 overall gear ratio, making it less likely to spin tires. Ford did this in most of their 3-4 speed automatics too.
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Snow is that white stuff that happens sometimes where it gets cold, right? Like in The Thing?
Anyway, finally got around to trying this.
screenshot.20-09-2022 17.26.19.png
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