: 2005 STS V6 Transmission Issue 1st-2nd Shift (with data)



CaddiDriver
01-20-12, 03:09 PM
I will start by saying the temperature outside has been -30C for the past week and my car began having this issue 2 days ago, could be related to cold temperatures or may just be coincidence. However will see if it clears up this weekend when temps are supposed to be back up to +2 degrees C. I have doubts that the warm weather will fix a broken transmission!

I've read about the TSB software update for the transmission though my symptoms do not seem to coincide with the "chuggle".

Problem: from rest, as you accelerate and the transmission shifts from 1st to 2nd gear, it seems to slip (takes longer than normal) before it engages into second and does so moderately abruptly and then very shortly after shifts into 3rd normally, then 4th and 5th with no issue. The problem is 1st-2nd. At light throttle the delay is less pronounced, under medium throttle seems to be the worst, and under 3/4 to full throttle there is no delay and the shift seems relatively normal.

The data I've found for shift points for the V6 is as follows:

Shift______TPS%______mph
1-2______25________10***
2-3______25________19
3-4______25________30
4-5______25________50

Similarly (excluding the first shift***), the data for my car since the issue:

Shift______TPS%______mph
1-2______25________15***
2-3______25________19
3-4______25________30
4-5______25________50

To conclude:
The shift is occurring 5mph too late and more firm of a shift than usual. This occurs every time, not intermittently and with the same effect depending on throttle position.

Any ideas, please post!

EChas3
01-20-12, 10:43 PM
Get to a dealer.

orange57
01-20-12, 11:35 PM
I agree with the above. You really need the dealer tools to diagnose these transmissions.

C&C
01-21-12, 05:55 AM
There are a lot of sensors (engine) bypassed in open loop operation. Until the engine goes into closed loop (warm), I would think, some operations might be less than ideal. The cold may be the culprit, but; as the vehicle warms and is driven enough miles to get fluids into a more normal operating temperature the shifts should revert back to normal. If not, then as suggested, some intervention may be warranted.

CaddiDriver
02-01-12, 07:20 PM
There are a lot of sensors (engine) bypassed in open loop operation. Until the engine goes into closed loop (warm), I would think, some operations might be less than ideal. The cold may be the culprit, but; as the vehicle warms and is driven enough miles to get fluids into a more normal operating temperature the shifts should revert back to normal. If not, then as suggested, some intervention may be warranted.

Well C&C, it appears you're some sort of super human. What you said does make sense and I think you may have been correct. I have been driving the car daily since I posted and just this weekend on Saturday (01/29/12) I drove the car on a 3 hour road trip and the weather was quite nice. Not exactly sure when but on Sunday (01/31/12) I noticed the car had reverted back to shifting absolutely 100% through all gears, even 1-2 shift. I had very low hopes but it has not given a hint of trouble since. I now truly suspect the cold fluid was very much a factor in this and may have allowed a valve to un-stick or something along these lines.

Hope this information helps anyone else who encounters a similar problem before going ahead with a major transmission service. Thanks to those who posted!

sharley24
02-10-12, 09:46 PM
I have a 2006 and have been having the same problem

carter's_sts
02-11-12, 01:01 AM
Is yours cold related? More details? Or like they said above, head to the dealer.

dkozloski
02-11-12, 05:40 PM
Who the hell cares about the 1-2 shift? At -50F I'm happy if the car moves at all.