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Transmission Not Shifting

fozzybear

Full Member
Joined
Jan 2, 2003
Messages
41
I have 2003 Z-71 with about 3000 miles on it and have noticed something odd in the last few days. When I leave my driveway the roadway I enter is at about a 5% grade. If I go downhill I have noticed that the Transmission is not shifting unless I let off the gas momentarily then it will after that hesitation. If I don't lift it will get to 4000 to 4500 rpm before shifting. Fluid levels are all OK and this only seems to do it when I go downhill. If I turn the other direction when leaving my driveway (uphill) I haven't noticed the problem. Any Ideas?
 

Badavv_Ms

SM 2003
Full Member
Joined
Feb 22, 2003
Messages
56
Fozzy,

Make sure the "TOW HAUL" is not engaged on your gearshift. It would be more apparent going downhill.
 

Shep

Full Member
Joined
Jan 27, 2003
Messages
16
Location
Raleigh, NC
I have been experiencing the exact same thing with my '03 Z-71 since day one (~2mos. ago). It will shift from 1st to 2nd normally, but will shift from 2nd to 3rd only at an excessively high RPM, unless I back off the pedal considerably. I am possitive the truck is not in tow/haul mode. I have not been very concerned about it since (for me) it ONLY does this when I first leave home (downhill) AND the truck is cold. Any thoughts on this would be great.

Just a total shot in the dark here: Does the PCM change shift points for a period of time when the engine/tranny is cold, like it does when tow/haul is engaged? And in this setting AND going downhill, it's making some sort of mistake?

Shep..
 
A

AVALANCHE_JIM

GUEST
Check your owners manual. I remember reading in mine the tranny will shift different to help warm the engine to operating temp.
 

fozzybear

Full Member
Joined
Jan 2, 2003
Messages
41
Shep that sounds exactly like what mine does. You just do a better job of explaining it than I do.
 
3

327chevy

GUEST
I have had trouble shifting from 1-2 in the Av after I put on a hypertech programmer, FPIK, and flowmaster 40. Before I put these on, the Av would not shift out of 2nd when the temp reached below zero. Does any body know whats wrong or have a similiar problem?
 
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