Harsher shifts on cold engine?
11-06-2006, 08:42 PM
#1
Harsher shifts on cold engine? I have the 4 speed auto with HPP+, and yes I chose to increase shift firmness. I've noticed for quite some time now that when the car is cold, the shifts seem a bit harder vs when the engine is at operating temperature (been like this for at least as long as I've had the HPP+, not sure if it happened before). I'm talking about partial throttle here (I never floor it until the engine has warmed up to operating temps). Anyone else experience this? No SES lights ever. Thanks.
11-06-2006, 09:48 PM
#2
Well there could be several possible issues ,
Simple would be fluild viscosity of course . Then with the tuning some of the trans ability to adapte presure fo temperature again fluild viscosity could be impeaded or even disabled.
I have seen this also on cars where the pcs has been replaced with a modulator since in this case to that function is not available ,
Simple would be fluild viscosity of course . Then with the tuning some of the trans ability to adapte presure fo temperature again fluild viscosity could be impeaded or even disabled.
I have seen this also on cars where the pcs has been replaced with a modulator since in this case to that function is not available ,
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11-07-2006, 05:54 PM
#3
Hmmm, using standard Dexron III, and had the tranny flushed 3 months ago (just for preventitive maintenance). Acts the same when cold. Shifts normally once warmed up.
What's a pcs?
What's a pcs?
11-07-2006, 09:46 PM
#5
So do I have a problem? It's been like this for several years, but I never had a SES cause of it. Tranny performs like a champ when warm, even at WOT (at that point, the tires chirp in 2nd). Just seems a bit harsh even when shifting from 1-2 at lower RPM's. Again, only when cold (more apparent as the ambient temps start falling to the 40s and lower). Thanks.
11-07-2006, 09:49 PM
#6
Tech Resident
my car shifts a little harder when the tranny is ice cold also. bone stock 4L60E, changed the fluids ~2 months ago. the light throttle shifts when the tranny is cold, particularly the 1-2 shift is a little firmer than when it warms up, and honestly, i like it better that way 
but seriously though, i'm pretty sure it's normal. the ATF is colder and isn't as fluid so the pressure inside is probably a little greater. once it's warmed up, it'll become more fluid and the shifts will soften a little. also, things expand with heat, so the tranny internals expanding a little bit once heated up will also decrease pressure. at least that makes sense in my mind.
but seriously though, i'm pretty sure it's normal. the ATF is colder and isn't as fluid so the pressure inside is probably a little greater. once it's warmed up, it'll become more fluid and the shifts will soften a little. also, things expand with heat, so the tranny internals expanding a little bit once heated up will also decrease pressure. at least that makes sense in my mind.
11-07-2006, 10:37 PM
#7
Ok, just wanted to make sure. Seems I'm not the only one. And since I'm not getting SES lights, I should be ok. Yes, I am talking about ice cold. Definitely not as apparent over the warmer summer months.
Forgot to add, the car does not jerk or even make a banging noise when shifting at colder temps, just feels much firmer when very cold.
Forgot to add, the car does not jerk or even make a banging noise when shifting at colder temps, just feels much firmer when very cold.
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03-10-2007, 06:28 AM
#8
YEah, resurrecting a dead thread again!
Still strange that this happens when ice cold. I mean, I barely touch the pedal, and it still shifts pretty hard as low as 2000 rpm. As I said before once warm, all is normal. I don't think I have codes since I do not have a SES light.
Still strange that this happens when ice cold. I mean, I barely touch the pedal, and it still shifts pretty hard as low as 2000 rpm. As I said before once warm, all is normal. I don't think I have codes since I do not have a SES light.
03-10-2007, 10:40 AM
#9
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All the cars I've ever owned have done this.
That includes my Grand Prix, Trans Am, and my girlfriend's Taurass that's about to fall apart.
Shifts are always softer/smoother after its warmed up.
That includes my Grand Prix, Trans Am, and my girlfriend's Taurass that's about to fall apart.
Shifts are always softer/smoother after its warmed up.