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Transmission Won't Stay In 1st

DavidC166

Full Member
Joined
Jun 4, 2002
Messages
146
Location
Fort Myers, FL
I searched but found nothing for this... is this a something unique to the Av, or a condition of HPP3 ??

Just playing around tonight for kicks, I decided to do a little manual shifting of the tranny... you know, drop it to "1" and go, then manually move the selector to "2". Okay, I know that this is "not recommended", but I did find something interesting. Under a heavy foot (not quite WOT), I found that the tranny would stay in 1st until I selected 2nd. However, under "normal" acceleration, it would kick to 2nd around 2000 RPM even tho' the selector still said 1st (I didn't expect the selector to change, but then again, I didn't expect the tranny to change either). Is it GMs way of keeping dummies from blowing up their trannies ?? Interestingly enough, it would not kick back down to 1st (around 25-30mph) even with WOT !!! (I figured that the HPP3 programming would kick in - nope [I'm at +4 on the 1-2 shift]) I didn't get a chance to see what tow/haul would do, but I was interested to see if anyone else has experienced this, or if anyone has an answer.

DavidC166
 
DaveC166,,,

The reason the tranny wouldn't hold 1st under normal throttle, is because it holds the gear selected only based on engine "load" measured by the PCM... Higher engine "load" in 1st will make it shift later ... The reason it didn't downshift back to 1st when you had it in second, is because our trannies have a "2nd gear start" feature for snow or slippery conditions... Selecting 2nd will hold second even off the line and will not downshift to first because it locks out first... It will however shift to 3rd if the load and throttle position dictates...

FYI, if you hold it in first, and keep it floored, it will spool right up to where the rev limiter is set and activate it ... (before I had the programmer, I could hold each shift until 5800 RPM or so by shifting manually... Cool huh?)

Hope this answers your question... ?(y)

11H
 
11H,
Thanks for the info.... guess I've been driving Fords too long. I was used to putting it in a a gear and having it stay there. The start in second feature makes sense too. However, I did notice today that if you are moving at speed (25-30) and downshift the selector from (D) to 1st or 2nd, it will drop to that gear... that makes me happy in case I'm towing down a grade and need a little more control. Aren't the GM guys smart :)

Thanks again,
DavidC166
 
As 11H said, not a programmer problem
My 2002/Z71 acts the same

If I leave it in first and excellerate firmly, it will up shift to second, and if you let off the throttle, it automaticly downshifts back to first, without even touching the shift lever

Come in very handy, for those short frequent, stop lights>>>>>>> and- I - like - it >> ;D
 
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